[for-next][PATCH 00/18] tracing: Fixes and trace-seq updates

[for-next][PATCH 00/18] tracing: Fixes and trace-seq updates

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 8e2e095cbecad21078332cd83ae7e61ecfe12c59


Steven Rostedt (Red Hat) (18):
      tracing: Fix race of function probes counting
      ftrace/x86: Add frames pointers to trampoline as necessary
      ftrace/x86/extable: Add is_ftrace_trampoline() function
      x86/kvm/tracing: Use helper function trace_seq_buffer_ptr()
      RAS/tracing: Use trace_seq_buffer_ptr() helper instead of open coded
      tracing: Fix trace_seq_bitmask() to start at current position
      tracing: Add trace_seq_has_overflowed() and trace_handle_return()
      blktrace/tracing: Use trace_seq_has_overflowed() helper function
      ring-buffer: Remove check of trace_seq_{puts,printf}() return values
      tracing: Have branch tracer use trace_handle_return() helper function
      tracing: Have function_graph use trace_seq_has_overflowed()
      kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks
      tracing: Do not check return values of trace_seq_p*() for mmio tracer
      tracing/probes: Do not use return value of trace_seq_printf()
      tracing/uprobes: Do not use return values of trace_seq_printf()
      tracing: Do not use return values of trace_seq_printf() in syscall tracing
      tracing: Remove return values of most trace_seq_*() functions
      tracing: Fix return value of ftrace_raw_output_prep()

----
 arch/x86/kernel/ftrace.c             |   9 +-
 arch/x86/kernel/mcount_64.S          |  41 ++++
 arch/x86/kvm/mmutrace.h              |   4 +-
 drivers/firmware/efi/cper.c          |   2 +-
 include/linux/ftrace.h               |   8 +
 include/linux/ftrace_event.h         |  11 +
 include/linux/trace_seq.h            |  49 ++--
 include/trace/ftrace.h               |   8 +-
 kernel/extable.c                     |   7 +-
 kernel/trace/blktrace.c              | 148 ++++++-------
 kernel/trace/ftrace.c                |  38 ++++
 kernel/trace/ring_buffer.c           |  75 +++----
 kernel/trace/trace.c                 |  69 +++---
 kernel/trace/trace.h                 |   3 +-
 kernel/trace/trace_branch.c          |  15 +-
 kernel/trace/trace_functions.c       | 117 ++++++++--
 kernel/trace/trace_functions_graph.c | 382 ++++++++++----------------------
 kernel/trace/trace_kprobe.c          |  42 ++--
 kernel/trace/trace_mmiotrace.c       |  52 ++---
 kernel/trace/trace_output.c          | 417 ++++++++++++++---------------------
 kernel/trace/trace_output.h          |  16 +-
 kernel/trace/trace_probe.c           |  10 +-
 kernel/trace/trace_seq.c             |  86 ++------
 kernel/trace/trace_syscalls.c        |  47 ++--
 kernel/trace/trace_uprobe.c          |  23 +-
 25 files changed, 768 insertions(+), 911 deletions(-)

[for-next][PATCH 01/18] tracing: Fix race of function probes counting

[Steven Rostedt]

[-- Attachment #1: 0001-tracing-Fix-race-of-function-probes-counting.patch --]
[-- Type: text/plain, Size: 5654 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The function probe counting for traceon and traceoff suffered a race
condition where if the probe was executing on two or more CPUs at the
same time, it could decrement the counter by more than one when
disabling (or enabling) the tracer only once.

The way the traceon and traceoff probes are suppose to work is that
they disable (or enable) tracing once per count. If a user were to
echo 'schedule:traceoff:3' into set_ftrace_filter, then when the
schedule function was called, it would disable tracing. But the count
should only be decremented once (to 2). Then if the user enabled tracing
again (via tracing_on file), the next call to schedule would disable
tracing again and the count would be decremented to 1.

But if multiple CPUS called schedule at the same time, it is possible
that the count would be decremented more than once because of the
simple "count--" used.

By reading the count into a local variable and using memory barriers
we can guarantee that the count would only be decremented once per
disable (or enable).

The stack trace probe had a similar race, but here the stack trace will
decrement for each time it is called. But this had the read-modify-
write race, where it could stack trace more than the number of times
that was specified. This case we use a cmpxchg to stack trace only the
number of times specified.

The dump probes can still use the old "update_count()" function as
they only run once, and that is controlled by the dump logic
itself.

Link: http://lkml.kernel.org/r/20141118134643.4b550ee4@gandalf.local.home

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_functions.c | 117 +++++++++++++++++++++++++++++++++--------
 1 file changed, 96 insertions(+), 21 deletions(-)

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index a8e0c7666164..973db52eb070 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -261,37 +261,74 @@ static struct tracer function_trace __tracer_data =
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-static int update_count(void **data)
+static void update_traceon_count(void **data, int on)
 {
-	unsigned long *count = (long *)data;
+	long *count = (long *)data;
+	long old_count = *count;
 
-	if (!*count)
-		return 0;
+	/*
+	 * Tracing gets disabled (or enabled) once per count.
+	 * This function can be called at the same time on mulitple CPUs.
+	 * It is fine if both disable (or enable) tracing, as disabling
+	 * (or enabling) the second time doesn't do anything as the
+	 * state of the tracer is already disabled (or enabled).
+	 * What needs to be synchronized in this case is that the count
+	 * only gets decremented once, even if the tracer is disabled
+	 * (or enabled) twice, as the second one is really a nop.
+	 *
+	 * The memory barriers guarantee that we only decrement the
+	 * counter once. First the count is read to a local variable
+	 * and a read barrier is used to make sure that it is loaded
+	 * before checking if the tracer is in the state we want.
+	 * If the tracer is not in the state we want, then the count
+	 * is guaranteed to be the old count.
+	 *
+	 * Next the tracer is set to the state we want (disabled or enabled)
+	 * then a write memory barrier is used to make sure that
+	 * the new state is visible before changing the counter by
+	 * one minus the old counter. This guarantees that another CPU
+	 * executing this code will see the new state before seeing
+	 * the new counter value, and would not do anthing if the new
+	 * counter is seen.
+	 *
+	 * Note, there is no synchronization between this and a user
+	 * setting the tracing_on file. But we currently don't care
+	 * about that.
+	 */
+	if (!old_count)
+		return;
 
-	if (*count != -1)
-		(*count)--;
+	/* Make sure we see count before checking tracing state */
+	smp_rmb();
 
-	return 1;
+	if (on == !!tracing_is_on())
+		return;
+
+	if (on)
+		tracing_on();
+	else
+		tracing_off();
+
+	/* unlimited? */
+	if (old_count == -1)
+		return;
+
+	/* Make sure tracing state is visible before updating count */
+	smp_wmb();
+
+	*count = old_count - 1;
 }
 
 static void
 ftrace_traceon_count(unsigned long ip, unsigned long parent_ip, void **data)
 {
-	if (tracing_is_on())
-		return;
-
-	if (update_count(data))
-		tracing_on();
+	update_traceon_count(data, 1);
 }
 
 static void
 ftrace_traceoff_count(unsigned long ip, unsigned long parent_ip, void **data)
 {
-	if (!tracing_is_on())
-		return;
-
-	if (update_count(data))
-		tracing_off();
+	update_traceon_count(data, 0);
 }
 
 static void
@@ -330,11 +367,49 @@ ftrace_stacktrace(unsigned long ip, unsigned long parent_ip, void **data)
 static void
 ftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, void **data)
 {
-	if (!tracing_is_on())
-		return;
+	long *count = (long *)data;
+	long old_count;
+	long new_count;
 
-	if (update_count(data))
-		trace_dump_stack(STACK_SKIP);
+	/*
+	 * Stack traces should only execute the number of times the
+	 * user specified in the counter.
+	 */
+	do {
+
+		if (!tracing_is_on())
+			return;
+
+		old_count = *count;
+
+		if (!old_count)
+			return;
+
+		/* unlimited? */
+		if (old_count == -1) {
+			trace_dump_stack(STACK_SKIP);
+			return;
+		}
+
+		new_count = old_count - 1;
+		new_count = cmpxchg(count, old_count, new_count);
+		if (new_count == old_count)
+			trace_dump_stack(STACK_SKIP);
+
+	} while (new_count != old_count);
+}
+
+static int update_count(void **data)
+{
+	unsigned long *count = (long *)data;
+
+	if (!*count)
+		return 0;
+
+	if (*count != -1)
+		(*count)--;
+
+	return 1;
 }
 
 static void
-- 
2.1.1

[for-next][PATCH 02/18] ftrace/x86: Add frames pointers to trampoline as necessary

[Steven Rostedt]

[-- Attachment #1: 0002-ftrace-x86-Add-frames-pointers-to-trampoline-as-nece.patch --]
[-- Type: text/plain, Size: 2881 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

When CONFIG_FRAME_POINTERS are enabled, it is required that the
ftrace_caller and ftrace_regs_caller trampolines set up frame pointers
otherwise a stack trace from a function call wont print the functions
that called the trampoline. This is due to a check in
__save_stack_address():

 #ifdef CONFIG_FRAME_POINTER
	if (!reliable)
		return;
 #endif

The "reliable" variable is only set if the function address is equal to
contents of the address before the address the frame pointer register
points to. If the frame pointer is not set up for the ftrace caller
then this will fail the reliable test. It will miss the function that
called the trampoline. Worse yet, if fentry is used (gcc 4.6 and
beyond), it will also miss the parent, as the fentry is called before
the stack frame is set up. That means the bp frame pointer points
to the stack of just before the parent function was called.

Link: http://lkml.kernel.org/r/20141119034829.355440340@goodmis.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: stable@vger.kernel.org # 3.7+
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/x86/kernel/mcount_64.S | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/arch/x86/kernel/mcount_64.S b/arch/x86/kernel/mcount_64.S
index 42f0cdd20baf..35a793fa4bba 100644
--- a/arch/x86/kernel/mcount_64.S
+++ b/arch/x86/kernel/mcount_64.S
@@ -47,14 +47,51 @@ GLOBAL(\trace_label)
 #endif
 .endm
 
+#ifdef CONFIG_FRAME_POINTER
+/*
+ * Stack traces will stop at the ftrace trampoline if the frame pointer
+ * is not set up properly. If fentry is used, we need to save a frame
+ * pointer for the parent as well as the function traced, because the
+ * fentry is called before the stack frame is set up, where as mcount
+ * is called afterward.
+ */
+.macro create_frame parent rip
+#ifdef CC_USING_FENTRY
+	pushq \parent
+	pushq %rbp
+	movq %rsp, %rbp
+#endif
+	pushq \rip
+	pushq %rbp
+	movq %rsp, %rbp
+.endm
+
+.macro restore_frame
+#ifdef CC_USING_FENTRY
+	addq $16, %rsp
+#endif
+	popq %rbp
+	addq $8, %rsp
+.endm
+#else
+.macro create_frame parent rip
+.endm
+.macro restore_frame
+.endm
+#endif /* CONFIG_FRAME_POINTER */
+
 ENTRY(ftrace_caller)
 	ftrace_caller_setup ftrace_caller_op_ptr
 	/* regs go into 4th parameter (but make it NULL) */
 	movq $0, %rcx
 
+	create_frame %rsi, %rdi
+
 GLOBAL(ftrace_call)
 	call ftrace_stub
 
+	restore_frame
+
 	MCOUNT_RESTORE_FRAME
 
 	/*
@@ -105,9 +142,13 @@ ENTRY(ftrace_regs_caller)
 	/* regs go into 4th parameter */
 	leaq (%rsp), %rcx
 
+	create_frame %rsi, %rdi
+
 GLOBAL(ftrace_regs_call)
 	call ftrace_stub
 
+	restore_frame
+
 	/* Copy flags back to SS, to restore them */
 	movq EFLAGS(%rsp), %rax
 	movq %rax, SS(%rsp)
-- 
2.1.1

[for-next][PATCH 03/18] ftrace/x86/extable: Add is_ftrace_trampoline() function

[Steven Rostedt]

[-- Attachment #1: 0003-ftrace-x86-extable-Add-is_ftrace_trampoline-function.patch --]
[-- Type: text/plain, Size: 6509 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Stack traces that happen from function tracing check if the address
on the stack is a __kernel_text_address(). That is, is the address
kernel code. This calls core_kernel_text() which returns true
if the address is part of the builtin kernel code. It also calls
is_module_text_address() which returns true if the address belongs
to module code.

But what is missing is ftrace dynamically allocated trampolines.
These trampolines are allocated for individual ftrace_ops that
call the ftrace_ops callback functions directly. But if they do a
stack trace, the code checking the stack wont detect them as they
are neither core kernel code nor module address space.

Adding another field to ftrace_ops that also stores the size of
the trampoline assigned to it we can create a new function called
is_ftrace_trampoline() that returns true if the address is a
dynamically allocate ftrace trampoline. Note, it ignores trampolines
that are not dynamically allocated as they will return true with
the core_kernel_text() function.

Link: http://lkml.kernel.org/r/20141119034829.497125839@goodmis.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/x86/kernel/ftrace.c |  9 +++++++--
 include/linux/ftrace.h   |  8 ++++++++
 kernel/extable.c         |  7 ++++++-
 kernel/trace/ftrace.c    | 38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 1aea94d336c7..60881d919432 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -712,7 +712,8 @@ union ftrace_op_code_union {
 	} __attribute__((packed));
 };
 
-static unsigned long create_trampoline(struct ftrace_ops *ops)
+static unsigned long
+create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
 {
 	unsigned const char *jmp;
 	unsigned long start_offset;
@@ -749,6 +750,8 @@ static unsigned long create_trampoline(struct ftrace_ops *ops)
 	if (!trampoline)
 		return 0;
 
+	*tramp_size = size + MCOUNT_INSN_SIZE + sizeof(void *);
+
 	/* Copy ftrace_caller onto the trampoline memory */
 	ret = probe_kernel_read(trampoline, (void *)start_offset, size);
 	if (WARN_ON(ret < 0)) {
@@ -819,6 +822,7 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
 	unsigned char *new;
 	unsigned long offset;
 	unsigned long ip;
+	unsigned int size;
 	int ret;
 
 	if (ops->trampoline) {
@@ -829,9 +833,10 @@ void arch_ftrace_update_trampoline(struct ftrace_ops *ops)
 		if (!(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
 			return;
 	} else {
-		ops->trampoline = create_trampoline(ops);
+		ops->trampoline = create_trampoline(ops, &size);
 		if (!ops->trampoline)
 			return;
+		ops->trampoline_size = size;
 	}
 
 	offset = calc_trampoline_call_offset(ops->flags & FTRACE_OPS_FL_SAVE_REGS);
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 619e37cc17fd..7b2616fa2472 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -150,6 +150,7 @@ struct ftrace_ops {
 	struct ftrace_ops_hash		*func_hash;
 	struct ftrace_ops_hash		old_hash;
 	unsigned long			trampoline;
+	unsigned long			trampoline_size;
 #endif
 };
 
@@ -297,6 +298,8 @@ extern int ftrace_text_reserved(const void *start, const void *end);
 
 extern int ftrace_nr_registered_ops(void);
 
+bool is_ftrace_trampoline(unsigned long addr);
+
 /*
  * The dyn_ftrace record's flags field is split into two parts.
  * the first part which is '0-FTRACE_REF_MAX' is a counter of
@@ -596,6 +599,11 @@ static inline ssize_t ftrace_notrace_write(struct file *file, const char __user
 			     size_t cnt, loff_t *ppos) { return -ENODEV; }
 static inline int
 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
+
+static inline bool is_ftrace_trampoline(unsigned long addr)
+{
+	return false;
+}
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 /* totally disable ftrace - can not re-enable after this */
diff --git a/kernel/extable.c b/kernel/extable.c
index d8a6446adbcb..c98f926277a8 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -18,6 +18,7 @@
 #include <linux/ftrace.h>
 #include <linux/memory.h>
 #include <linux/module.h>
+#include <linux/ftrace.h>
 #include <linux/mutex.h>
 #include <linux/init.h>
 
@@ -102,6 +103,8 @@ int __kernel_text_address(unsigned long addr)
 		return 1;
 	if (is_module_text_address(addr))
 		return 1;
+	if (is_ftrace_trampoline(addr))
+		return 1;
 	/*
 	 * There might be init symbols in saved stacktraces.
 	 * Give those symbols a chance to be printed in
@@ -119,7 +122,9 @@ int kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return is_module_text_address(addr);
+	if (is_module_text_address(addr))
+		return 1;
+	return is_ftrace_trampoline(addr);
 }
 
 /*
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6233f9102179..fa0f36bb32e9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1117,6 +1117,43 @@ static struct ftrace_ops global_ops = {
 					  FTRACE_OPS_FL_INITIALIZED,
 };
 
+/*
+ * This is used by __kernel_text_address() to return true if the
+ * the address is on a dynamically allocated trampoline that would
+ * not return true for either core_kernel_text() or
+ * is_module_text_address().
+ */
+bool is_ftrace_trampoline(unsigned long addr)
+{
+	struct ftrace_ops *op;
+	bool ret = false;
+
+	/*
+	 * Some of the ops may be dynamically allocated,
+	 * they are freed after a synchronize_sched().
+	 */
+	preempt_disable_notrace();
+
+	do_for_each_ftrace_op(op, ftrace_ops_list) {
+		/*
+		 * This is to check for dynamically allocated trampolines.
+		 * Trampolines that are in kernel text will have
+		 * core_kernel_text() return true.
+		 */
+		if (op->trampoline && op->trampoline_size)
+			if (addr >= op->trampoline &&
+			    addr < op->trampoline + op->trampoline_size) {
+				ret = true;
+				goto out;
+			}
+	} while_for_each_ftrace_op(op);
+
+ out:
+	preempt_enable_notrace();
+
+	return ret;
+}
+
 struct ftrace_page {
 	struct ftrace_page	*next;
 	struct dyn_ftrace	*records;
@@ -5373,6 +5410,7 @@ static struct ftrace_ops graph_ops = {
 				   FTRACE_OPS_FL_STUB,
 #ifdef FTRACE_GRAPH_TRAMP_ADDR
 	.trampoline		= FTRACE_GRAPH_TRAMP_ADDR,
+	/* trampoline_size is only needed for dynamically allocated tramps */
 #endif
 	ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
 };
-- 
2.1.1

[for-next][PATCH 04/18] x86/kvm/tracing: Use helper function trace_seq_buffer_ptr()

[Steven Rostedt]

[-- Attachment #1: 0004-x86-kvm-tracing-Use-helper-function-trace_seq_buffer.patch --]
[-- Type: text/plain, Size: 1432 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

To allow for the restructiong of the trace_seq code, we need users
of it to use the helper functions instead of accessing the internals
of the trace_seq structure itself.

Link: http://lkml.kernel.org/r/20141104160221.585025609@goodmis.org

Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Mark Rustad <mark.d.rustad@intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/x86/kvm/mmutrace.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index 5aaf35641768..ce463a9cc8fb 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -22,7 +22,7 @@
 	__entry->unsync = sp->unsync;
 
 #define KVM_MMU_PAGE_PRINTK() ({				        \
-	const u32 saved_len = p->len;					\
+	const char *saved_ptr = trace_seq_buffer_ptr(p);		\
 	static const char *access_str[] = {			        \
 		"---", "--x", "w--", "w-x", "-u-", "-ux", "wu-", "wux"  \
 	};							        \
@@ -41,7 +41,7 @@
 			 role.nxe ? "" : "!",				\
 			 __entry->root_count,				\
 			 __entry->unsync ? "unsync" : "sync", 0);	\
-	p->buffer + saved_len;						\
+	saved_ptr;							\
 		})
 
 #define kvm_mmu_trace_pferr_flags       \
-- 
2.1.1

[for-next][PATCH 05/18] RAS/tracing: Use trace_seq_buffer_ptr() helper instead of open coded

[Steven Rostedt]

[-- Attachment #1: 0005-RAS-tracing-Use-trace_seq_buffer_ptr-helper-instead-.patch --]
[-- Type: text/plain, Size: 1201 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Use the helper function trace_seq_buffer_ptr() to get the current location
of the next buffer write of a trace_seq object, instead of open coding
it.

This facilitates the conversion of trace_seq to use seq_buf.

Tested-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 drivers/firmware/efi/cper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index 5b53d6183b6b..4fd9961d552e 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -294,7 +294,7 @@ void cper_mem_err_pack(const struct cper_sec_mem_err *mem,
 const char *cper_mem_err_unpack(struct trace_seq *p,
 				struct cper_mem_err_compact *cmem)
 {
-	const char *ret = p->buffer + p->len;
+	const char *ret = trace_seq_buffer_ptr(p);
 
 	if (cper_mem_err_location(cmem, rcd_decode_str))
 		trace_seq_printf(p, "%s", rcd_decode_str);
-- 
2.1.1

[for-next][PATCH 06/18] tracing: Fix trace_seq_bitmask() to start at current position

[Steven Rostedt]

[-- Attachment #1: 0006-tracing-Fix-trace_seq_bitmask-to-start-at-current-po.patch --]
[-- Type: text/plain, Size: 1111 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

In trace_seq_bitmask() it calls bitmap_scnprintf() not from the current
position of the trace_seq buffer (s->buffer + s->len), but instead from
the beginning of the buffer (s->buffer).

Luckily, the only user of this "ipi_raise tracepoint" uses it as the
first parameter, and as such, the start of the temp buffer in
include/trace/ftrace.h (see __get_bitmask()).

Reported-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_seq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 1f24ed99dca2..b100994a17fe 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -122,7 +122,7 @@ int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 	if (s->full || !len)
 		return 0;
 
-	ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits);
+	ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
 	s->len += ret;
 
 	return 1;
-- 
2.1.1

[for-next][PATCH 07/18] tracing: Add trace_seq_has_overflowed() and trace_handle_return()

[Steven Rostedt]

[-- Attachment #1: 0007-tracing-Add-trace_seq_has_overflowed-and-trace_handl.patch --]
[-- Type: text/plain, Size: 29495 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Adding a trace_seq_has_overflowed() which returns true if the trace_seq
had too much written into it allows us to simplify the code.

Instead of checking the return value of every call to trace_seq_printf()
and friends, they can all be called normally, and at the end we can
return !trace_seq_has_overflowed() instead.

Several functions also return TRACE_TYPE_PARTIAL_LINE when the trace_seq
overflowed and TRACE_TYPE_HANDLED otherwise. Another helper function
was created called trace_handle_return() which takes a trace_seq and
returns these enums. Using this helper function also simplifies the
code.

This change also makes it possible to remove the return values of
trace_seq_printf() and friends. They should instead just be
void functions.

Link: http://lkml.kernel.org/r/20141114011410.365183157@goodmis.org

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace_event.h |  11 ++
 include/linux/trace_seq.h    |  12 ++
 include/trace/ftrace.h       |   6 +-
 kernel/trace/trace.c         |  69 +++----
 kernel/trace/trace.h         |   1 +
 kernel/trace/trace_output.c  | 416 +++++++++++++++++--------------------------
 kernel/trace/trace_output.h  |  16 +-
 7 files changed, 231 insertions(+), 300 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 28672e87e910..0bebb5c348b8 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -138,6 +138,17 @@ enum print_line_t {
 	TRACE_TYPE_NO_CONSUME	= 3	/* Handled but ask to not consume */
 };
 
+/*
+ * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
+ * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
+ * simplifies those functions and keeps them in sync.
+ */
+static inline enum print_line_t trace_handle_return(struct trace_seq *s)
+{
+	return trace_seq_has_overflowed(s) ?
+		TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
+}
+
 void tracing_generic_entry_update(struct trace_entry *entry,
 				  unsigned long flags,
 				  int pc);
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index ea6c9dea79e3..07eda413dfcf 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -40,6 +40,18 @@ trace_seq_buffer_ptr(struct trace_seq *s)
 	return s->buffer + s->len;
 }
 
+/**
+ * trace_seq_has_overflowed - return true if the trace_seq took too much
+ * @s: trace sequence descriptor
+ *
+ * Returns true if too much data was added to the trace_seq and it is
+ * now full and will not take anymore.
+ */
+static inline bool trace_seq_has_overflowed(struct trace_seq *s)
+{
+	return s->full || s->len > PAGE_SIZE - 1;
+}
+
 /*
  * Currently only defined when tracing is enabled.
  */
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 26b4f2e13275..f13471b5d27a 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -280,11 +280,9 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags,	\
 	if (ret)							\
 		return ret;						\
 									\
-	ret = trace_seq_printf(s, print);				\
-	if (!ret)							\
-		return TRACE_TYPE_PARTIAL_LINE;				\
+	trace_seq_printf(s, print);					\
 									\
-	return TRACE_TYPE_HANDLED;					\
+	return trace_handle_return(s);					\
 }									\
 static struct trace_event_functions ftrace_event_type_funcs_##call = {	\
 	.trace			= ftrace_raw_output_##call,		\
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 44d561426700..3ce3c4ccfc94 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2649,24 +2649,21 @@ static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
 	event = ftrace_find_event(entry->type);
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
-			if (!trace_print_lat_context(iter))
-				goto partial;
-		} else {
-			if (!trace_print_context(iter))
-				goto partial;
-		}
+		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+			trace_print_lat_context(iter);
+		else
+			trace_print_context(iter);
 	}
 
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
 	if (event)
 		return event->funcs->trace(iter, sym_flags, event);
 
-	if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
-		goto partial;
+	trace_seq_printf(s, "Unknown type %d\n", entry->type);
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
@@ -2677,22 +2674,20 @@ static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
 
 	entry = iter->ent;
 
-	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		if (!trace_seq_printf(s, "%d %d %llu ",
-				      entry->pid, iter->cpu, iter->ts))
-			goto partial;
-	}
+	if (trace_flags & TRACE_ITER_CONTEXT_INFO)
+		trace_seq_printf(s, "%d %d %llu ",
+				 entry->pid, iter->cpu, iter->ts);
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
 
 	event = ftrace_find_event(entry->type);
 	if (event)
 		return event->funcs->raw(iter, 0, event);
 
-	if (!trace_seq_printf(s, "%d ?\n", entry->type))
-		goto partial;
+	trace_seq_printf(s, "%d ?\n", entry->type);
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
@@ -2705,9 +2700,11 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 	entry = iter->ent;
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
-		SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
-		SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
+		SEQ_PUT_HEX_FIELD(s, entry->pid);
+		SEQ_PUT_HEX_FIELD(s, iter->cpu);
+		SEQ_PUT_HEX_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
 	}
 
 	event = ftrace_find_event(entry->type);
@@ -2717,9 +2714,9 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 			return ret;
 	}
 
-	SEQ_PUT_FIELD_RET(s, newline);
+	SEQ_PUT_FIELD(s, newline);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
@@ -2731,9 +2728,11 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 	entry = iter->ent;
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
-		SEQ_PUT_FIELD_RET(s, entry->pid);
-		SEQ_PUT_FIELD_RET(s, iter->cpu);
-		SEQ_PUT_FIELD_RET(s, iter->ts);
+		SEQ_PUT_FIELD(s, entry->pid);
+		SEQ_PUT_FIELD(s, iter->cpu);
+		SEQ_PUT_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
 	}
 
 	event = ftrace_find_event(entry->type);
@@ -2779,10 +2778,12 @@ enum print_line_t print_trace_line(struct trace_iterator *iter)
 {
 	enum print_line_t ret;
 
-	if (iter->lost_events &&
-	    !trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
-				 iter->cpu, iter->lost_events))
-		return TRACE_TYPE_PARTIAL_LINE;
+	if (iter->lost_events) {
+		trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+				 iter->cpu, iter->lost_events);
+		if (trace_seq_has_overflowed(&iter->seq))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
 
 	if (iter->trace && iter->trace->print_line) {
 		ret = iter->trace->print_line(iter);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3376de623ea0..19418221b302 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -14,6 +14,7 @@
 #include <linux/trace_seq.h>
 #include <linux/ftrace_event.h>
 #include <linux/compiler.h>
+#include <linux/trace_seq.h>
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 #include <asm/unistd.h>		/* For NR_SYSCALLS	     */
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index cfa91de22e27..163c11b6b8ff 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -25,15 +25,12 @@ enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter)
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry = iter->ent;
 	struct bputs_entry *field;
-	int ret;
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_puts(s, field->str);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, field->str);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
@@ -41,15 +38,12 @@ enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry = iter->ent;
 	struct bprint_entry *field;
-	int ret;
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_bprintf(s, field->fmt, field->buf);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_bprintf(s, field->fmt, field->buf);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
@@ -57,15 +51,12 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter)
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry = iter->ent;
 	struct print_entry *field;
-	int ret;
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_puts(s, field->buf);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, field->buf);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 const char *
@@ -193,7 +184,6 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
 	struct trace_seq *s = &iter->seq;
 	struct trace_seq *p = &iter->tmp_seq;
 	struct trace_entry *entry;
-	int ret;
 
 	event = container_of(trace_event, struct ftrace_event_call, event);
 	entry = iter->ent;
@@ -204,8 +194,9 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
 	}
 
 	trace_seq_init(p);
-	ret = trace_seq_printf(s, "%s: ", ftrace_event_name(event));
-	if (!ret)
+	trace_seq_printf(s, "%s: ", ftrace_event_name(event));
+
+	if (trace_seq_has_overflowed(s))
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	return 0;
@@ -216,18 +207,11 @@ static int ftrace_output_raw(struct trace_iterator *iter, char *name,
 			     char *fmt, va_list ap)
 {
 	struct trace_seq *s = &iter->seq;
-	int ret;
 
-	ret = trace_seq_printf(s, "%s: ", name);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_vprintf(s, fmt, ap);
+	trace_seq_printf(s, "%s: ", name);
+	trace_seq_vprintf(s, fmt, ap);
 
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...)
@@ -260,7 +244,7 @@ static inline const char *kretprobed(const char *name)
 }
 #endif /* CONFIG_KRETPROBES */
 
-static int
+static void
 seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 {
 #ifdef CONFIG_KALLSYMS
@@ -271,12 +255,11 @@ seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
 
 	name = kretprobed(str);
 
-	return trace_seq_printf(s, fmt, name);
+	trace_seq_printf(s, fmt, name);
 #endif
-	return 1;
 }
 
-static int
+static void
 seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 		     unsigned long address)
 {
@@ -287,9 +270,8 @@ seq_print_sym_offset(struct trace_seq *s, const char *fmt,
 	sprint_symbol(str, address);
 	name = kretprobed(str);
 
-	return trace_seq_printf(s, fmt, name);
+	trace_seq_printf(s, fmt, name);
 #endif
-	return 1;
 }
 
 #ifndef CONFIG_64BIT
@@ -320,14 +302,14 @@ int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
 		if (file) {
 			ret = trace_seq_path(s, &file->f_path);
 			if (ret)
-				ret = trace_seq_printf(s, "[+0x%lx]",
-						       ip - vmstart);
+				trace_seq_printf(s, "[+0x%lx]",
+						 ip - vmstart);
 		}
 		up_read(&mm->mmap_sem);
 	}
 	if (ret && ((sym_flags & TRACE_ITER_SYM_ADDR) || !file))
-		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
-	return ret;
+		trace_seq_printf(s, " <" IP_FMT ">", ip);
+	return !trace_seq_has_overflowed(s);
 }
 
 int
@@ -335,7 +317,6 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 		      unsigned long sym_flags)
 {
 	struct mm_struct *mm = NULL;
-	int ret = 1;
 	unsigned int i;
 
 	if (trace_flags & TRACE_ITER_SYM_USEROBJ) {
@@ -354,48 +335,45 @@ seq_print_userip_objs(const struct userstack_entry *entry, struct trace_seq *s,
 	for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
 		unsigned long ip = entry->caller[i];
 
-		if (ip == ULONG_MAX || !ret)
+		if (ip == ULONG_MAX || trace_seq_has_overflowed(s))
 			break;
-		if (ret)
-			ret = trace_seq_puts(s, " => ");
+
+		trace_seq_puts(s, " => ");
+
 		if (!ip) {
-			if (ret)
-				ret = trace_seq_puts(s, "??");
-			if (ret)
-				ret = trace_seq_putc(s, '\n');
+			trace_seq_puts(s, "??");
+			trace_seq_putc(s, '\n');
 			continue;
 		}
-		if (!ret)
-			break;
-		if (ret)
-			ret = seq_print_user_ip(s, mm, ip, sym_flags);
-		ret = trace_seq_putc(s, '\n');
+
+		seq_print_user_ip(s, mm, ip, sym_flags);
+		trace_seq_putc(s, '\n');
 	}
 
 	if (mm)
 		mmput(mm);
-	return ret;
+
+	return !trace_seq_has_overflowed(s);
 }
 
 int
 seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
 {
-	int ret;
-
-	if (!ip)
-		return trace_seq_putc(s, '0');
+	if (!ip) {
+		trace_seq_putc(s, '0');
+		goto out;
+	}
 
 	if (sym_flags & TRACE_ITER_SYM_OFFSET)
-		ret = seq_print_sym_offset(s, "%s", ip);
+		seq_print_sym_offset(s, "%s", ip);
 	else
-		ret = seq_print_sym_short(s, "%s", ip);
-
-	if (!ret)
-		return 0;
+		seq_print_sym_short(s, "%s", ip);
 
 	if (sym_flags & TRACE_ITER_SYM_ADDR)
-		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
-	return ret;
+		trace_seq_printf(s, " <" IP_FMT ">", ip);
+
+ out:
+	return !trace_seq_has_overflowed(s);
 }
 
 /**
@@ -413,7 +391,6 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 	char irqs_off;
 	int hardirq;
 	int softirq;
-	int ret;
 
 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
 	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
@@ -445,16 +422,15 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 		softirq ? 's' :
 		'.';
 
-	if (!trace_seq_printf(s, "%c%c%c",
-			      irqs_off, need_resched, hardsoft_irq))
-		return 0;
+	trace_seq_printf(s, "%c%c%c",
+			 irqs_off, need_resched, hardsoft_irq);
 
 	if (entry->preempt_count)
-		ret = trace_seq_printf(s, "%x", entry->preempt_count);
+		trace_seq_printf(s, "%x", entry->preempt_count);
 	else
-		ret = trace_seq_putc(s, '.');
+		trace_seq_putc(s, '.');
 
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 static int
@@ -464,9 +440,8 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 
 	trace_find_cmdline(entry->pid, comm);
 
-	if (!trace_seq_printf(s, "%8.8s-%-5d %3d",
-			      comm, entry->pid, cpu))
-		return 0;
+	trace_seq_printf(s, "%8.8s-%-5d %3d",
+			 comm, entry->pid, cpu);
 
 	return trace_print_lat_fmt(s, entry);
 }
@@ -493,24 +468,29 @@ lat_print_timestamp(struct trace_iterator *iter, u64 next_ts)
 		unsigned long rel_usec = do_div(rel_ts, USEC_PER_MSEC);
 		unsigned long rel_msec = (unsigned long)rel_ts;
 
-		return trace_seq_printf(
-				s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
-				ns2usecs(iter->ts),
-				abs_msec, abs_usec,
-				rel_msec, rel_usec);
+		trace_seq_printf(
+			s, "[%08llx] %ld.%03ldms (+%ld.%03ldms): ",
+			ns2usecs(iter->ts),
+			abs_msec, abs_usec,
+			rel_msec, rel_usec);
+
 	} else if (verbose && !in_ns) {
-		return trace_seq_printf(
-				s, "[%016llx] %lld (+%lld): ",
-				iter->ts, abs_ts, rel_ts);
+		trace_seq_printf(
+			s, "[%016llx] %lld (+%lld): ",
+			iter->ts, abs_ts, rel_ts);
+
 	} else if (!verbose && in_ns) {
-		return trace_seq_printf(
-				s, " %4lldus%c: ",
-				abs_ts,
-				rel_ts > preempt_mark_thresh_us ? '!' :
-				  rel_ts > 1 ? '+' : ' ');
+		trace_seq_printf(
+			s, " %4lldus%c: ",
+			abs_ts,
+			rel_ts > preempt_mark_thresh_us ? '!' :
+			rel_ts > 1 ? '+' : ' ');
+
 	} else { /* !verbose && !in_ns */
-		return trace_seq_printf(s, " %4lld: ", abs_ts);
+		trace_seq_printf(s, " %4lld: ", abs_ts);
 	}
+
+	return !trace_seq_has_overflowed(s);
 }
 
 int trace_print_context(struct trace_iterator *iter)
@@ -520,34 +500,29 @@ int trace_print_context(struct trace_iterator *iter)
 	unsigned long long t;
 	unsigned long secs, usec_rem;
 	char comm[TASK_COMM_LEN];
-	int ret;
 
 	trace_find_cmdline(entry->pid, comm);
 
-	ret = trace_seq_printf(s, "%16s-%-5d [%03d] ",
+	trace_seq_printf(s, "%16s-%-5d [%03d] ",
 			       comm, entry->pid, iter->cpu);
-	if (!ret)
-		return 0;
 
-	if (trace_flags & TRACE_ITER_IRQ_INFO) {
-		ret = trace_print_lat_fmt(s, entry);
-		if (!ret)
-			return 0;
-	}
+	if (trace_flags & TRACE_ITER_IRQ_INFO)
+		trace_print_lat_fmt(s, entry);
 
 	if (iter->iter_flags & TRACE_FILE_TIME_IN_NS) {
 		t = ns2usecs(iter->ts);
 		usec_rem = do_div(t, USEC_PER_SEC);
 		secs = (unsigned long)t;
-		return trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
+		trace_seq_printf(s, " %5lu.%06lu: ", secs, usec_rem);
 	} else
-		return trace_seq_printf(s, " %12llu: ", iter->ts);
+		trace_seq_printf(s, " %12llu: ", iter->ts);
+
+	return !trace_seq_has_overflowed(s);
 }
 
 int trace_print_lat_context(struct trace_iterator *iter)
 {
 	u64 next_ts;
-	int ret;
 	/* trace_find_next_entry will reset ent_size */
 	int ent_size = iter->ent_size;
 	struct trace_seq *s = &iter->seq;
@@ -567,18 +542,17 @@ int trace_print_lat_context(struct trace_iterator *iter)
 
 		trace_find_cmdline(entry->pid, comm);
 
-		ret = trace_seq_printf(
-				s, "%16s %5d %3d %d %08x %08lx ",
-				comm, entry->pid, iter->cpu, entry->flags,
-				entry->preempt_count, iter->idx);
+		trace_seq_printf(
+			s, "%16s %5d %3d %d %08x %08lx ",
+			comm, entry->pid, iter->cpu, entry->flags,
+			entry->preempt_count, iter->idx);
 	} else {
-		ret = lat_print_generic(s, entry, iter->cpu);
+		lat_print_generic(s, entry, iter->cpu);
 	}
 
-	if (ret)
-		ret = lat_print_timestamp(iter, next_ts);
+	lat_print_timestamp(iter, next_ts);
 
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
@@ -764,10 +738,9 @@ EXPORT_SYMBOL_GPL(unregister_ftrace_event);
 enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags,
 				  struct trace_event *event)
 {
-	if (!trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq, "type: %d\n", iter->ent->type);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 /* TRACE_FN */
@@ -779,24 +752,16 @@ static enum print_line_t trace_fn_trace(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
 
 	if ((flags & TRACE_ITER_PRINT_PARENT) && field->parent_ip) {
-		if (!trace_seq_puts(s, " <-"))
-			goto partial;
-		if (!seq_print_ip_sym(s,
-				      field->parent_ip,
-				      flags))
-			goto partial;
+		trace_seq_puts(s, " <-");
+		seq_print_ip_sym(s, field->parent_ip, flags);
 	}
-	if (!trace_seq_putc(s, '\n'))
-		goto partial;
 
-	return TRACE_TYPE_HANDLED;
+	trace_seq_putc(s, '\n');
 
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
@@ -806,12 +771,11 @@ static enum print_line_t trace_fn_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(&iter->seq, "%lx %lx\n",
-			      field->ip,
-			      field->parent_ip))
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(&iter->seq, "%lx %lx\n",
+			 field->ip,
+			 field->parent_ip);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
@@ -822,10 +786,10 @@ static enum print_line_t trace_fn_hex(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	SEQ_PUT_HEX_FIELD_RET(s, field->ip);
-	SEQ_PUT_HEX_FIELD_RET(s, field->parent_ip);
+	SEQ_PUT_HEX_FIELD(s, field->ip);
+	SEQ_PUT_HEX_FIELD(s, field->parent_ip);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
@@ -836,10 +800,10 @@ static enum print_line_t trace_fn_bin(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	SEQ_PUT_FIELD_RET(s, field->ip);
-	SEQ_PUT_FIELD_RET(s, field->parent_ip);
+	SEQ_PUT_FIELD(s, field->ip);
+	SEQ_PUT_FIELD(s, field->parent_ip);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_fn_funcs = {
@@ -868,18 +832,17 @@ static enum print_line_t trace_ctxwake_print(struct trace_iterator *iter,
 	T = task_state_char(field->next_state);
 	S = task_state_char(field->prev_state);
 	trace_find_cmdline(field->next_pid, comm);
-	if (!trace_seq_printf(&iter->seq,
-			      " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
-			      field->prev_pid,
-			      field->prev_prio,
-			      S, delim,
-			      field->next_cpu,
-			      field->next_pid,
-			      field->next_prio,
-			      T, comm))
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_printf(&iter->seq,
+			 " %5d:%3d:%c %s [%03d] %5d:%3d:%c %s\n",
+			 field->prev_pid,
+			 field->prev_prio,
+			 S, delim,
+			 field->next_cpu,
+			 field->next_pid,
+			 field->next_prio,
+			 T, comm);
+
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t trace_ctx_print(struct trace_iterator *iter, int flags,
@@ -904,17 +867,16 @@ static int trace_ctxwake_raw(struct trace_iterator *iter, char S)
 	if (!S)
 		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
-	if (!trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
-			      field->prev_pid,
-			      field->prev_prio,
-			      S,
-			      field->next_cpu,
-			      field->next_pid,
-			      field->next_prio,
-			      T))
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_printf(&iter->seq, "%d %d %c %d %d %d %c\n",
+			 field->prev_pid,
+			 field->prev_prio,
+			 S,
+			 field->next_cpu,
+			 field->next_pid,
+			 field->next_prio,
+			 T);
+
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t trace_ctx_raw(struct trace_iterator *iter, int flags,
@@ -942,15 +904,15 @@ static int trace_ctxwake_hex(struct trace_iterator *iter, char S)
 		S = task_state_char(field->prev_state);
 	T = task_state_char(field->next_state);
 
-	SEQ_PUT_HEX_FIELD_RET(s, field->prev_pid);
-	SEQ_PUT_HEX_FIELD_RET(s, field->prev_prio);
-	SEQ_PUT_HEX_FIELD_RET(s, S);
-	SEQ_PUT_HEX_FIELD_RET(s, field->next_cpu);
-	SEQ_PUT_HEX_FIELD_RET(s, field->next_pid);
-	SEQ_PUT_HEX_FIELD_RET(s, field->next_prio);
-	SEQ_PUT_HEX_FIELD_RET(s, T);
+	SEQ_PUT_HEX_FIELD(s, field->prev_pid);
+	SEQ_PUT_HEX_FIELD(s, field->prev_prio);
+	SEQ_PUT_HEX_FIELD(s, S);
+	SEQ_PUT_HEX_FIELD(s, field->next_cpu);
+	SEQ_PUT_HEX_FIELD(s, field->next_pid);
+	SEQ_PUT_HEX_FIELD(s, field->next_prio);
+	SEQ_PUT_HEX_FIELD(s, T);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_ctx_hex(struct trace_iterator *iter, int flags,
@@ -973,15 +935,15 @@ static enum print_line_t trace_ctxwake_bin(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	SEQ_PUT_FIELD_RET(s, field->prev_pid);
-	SEQ_PUT_FIELD_RET(s, field->prev_prio);
-	SEQ_PUT_FIELD_RET(s, field->prev_state);
-	SEQ_PUT_FIELD_RET(s, field->next_cpu);
-	SEQ_PUT_FIELD_RET(s, field->next_pid);
-	SEQ_PUT_FIELD_RET(s, field->next_prio);
-	SEQ_PUT_FIELD_RET(s, field->next_state);
+	SEQ_PUT_FIELD(s, field->prev_pid);
+	SEQ_PUT_FIELD(s, field->prev_prio);
+	SEQ_PUT_FIELD(s, field->prev_state);
+	SEQ_PUT_FIELD(s, field->next_cpu);
+	SEQ_PUT_FIELD(s, field->next_pid);
+	SEQ_PUT_FIELD(s, field->next_prio);
+	SEQ_PUT_FIELD(s, field->next_state);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_ctx_funcs = {
@@ -1021,23 +983,19 @@ static enum print_line_t trace_stack_print(struct trace_iterator *iter,
 	trace_assign_type(field, iter->ent);
 	end = (unsigned long *)((long)iter->ent + iter->ent_size);
 
-	if (!trace_seq_puts(s, "<stack trace>\n"))
-		goto partial;
+	trace_seq_puts(s, "<stack trace>\n");
 
 	for (p = field->caller; p && *p != ULONG_MAX && p < end; p++) {
-		if (!trace_seq_puts(s, " => "))
-			goto partial;
 
-		if (!seq_print_ip_sym(s, *p, flags))
-			goto partial;
-		if (!trace_seq_putc(s, '\n'))
-			goto partial;
-	}
+		if (trace_seq_has_overflowed(s))
+			break;
 
-	return TRACE_TYPE_HANDLED;
+		trace_seq_puts(s, " => ");
+		seq_print_ip_sym(s, *p, flags);
+		trace_seq_putc(s, '\n');
+	}
 
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_stack_funcs = {
@@ -1058,16 +1016,10 @@ static enum print_line_t trace_user_stack_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_puts(s, "<user stack trace>\n"))
-		goto partial;
-
-	if (!seq_print_userip_objs(field, s, flags))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_puts(s, "<user stack trace>\n");
+	seq_print_userip_objs(field, s, flags);
 
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_user_stack_funcs = {
@@ -1090,19 +1042,11 @@ trace_bputs_print(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, entry);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_puts(s, ": ");
+	trace_seq_puts(s, field->str);
 
-	if (!trace_seq_puts(s, ": "))
-		goto partial;
-
-	if (!trace_seq_puts(s, field->str))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 
@@ -1115,16 +1059,10 @@ trace_bputs_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(s, ": %lx : ", field->ip))
-		goto partial;
-
-	if (!trace_seq_puts(s, field->str))
-		goto partial;
+	trace_seq_printf(s, ": %lx : ", field->ip);
+	trace_seq_puts(s, field->str);
 
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_bputs_funcs = {
@@ -1148,19 +1086,11 @@ trace_bprint_print(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, entry);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
-
-	if (!trace_seq_puts(s, ": "))
-		goto partial;
-
-	if (!trace_seq_bprintf(s, field->fmt, field->buf))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_puts(s, ": ");
+	trace_seq_bprintf(s, field->fmt, field->buf);
 
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 
@@ -1173,16 +1103,10 @@ trace_bprint_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(s, ": %lx : ", field->ip))
-		goto partial;
-
-	if (!trace_seq_bprintf(s, field->fmt, field->buf))
-		goto partial;
+	trace_seq_printf(s, ": %lx : ", field->ip);
+	trace_seq_bprintf(s, field->fmt, field->buf);
 
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static struct trace_event_functions trace_bprint_funcs = {
@@ -1204,16 +1128,10 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!seq_print_ip_sym(s, field->ip, flags))
-		goto partial;
-
-	if (!trace_seq_printf(s, ": %s", field->buf))
-		goto partial;
+	seq_print_ip_sym(s, field->ip, flags);
+	trace_seq_printf(s, ": %s", field->buf);
 
-	return TRACE_TYPE_HANDLED;
-
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
@@ -1223,13 +1141,9 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, iter->ent);
 
-	if (!trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf))
-		goto partial;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
 
- partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	return trace_handle_return(&iter->seq);
 }
 
 static struct trace_event_functions trace_print_funcs = {
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 80b25b585a70..8ef2c40efb3c 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -35,17 +35,11 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry);
 extern int __unregister_ftrace_event(struct trace_event *event);
 extern struct rw_semaphore trace_event_sem;
 
-#define SEQ_PUT_FIELD_RET(s, x)				\
-do {							\
-	if (!trace_seq_putmem(s, &(x), sizeof(x)))	\
-		return TRACE_TYPE_PARTIAL_LINE;		\
-} while (0)
-
-#define SEQ_PUT_HEX_FIELD_RET(s, x)			\
-do {							\
-	if (!trace_seq_putmem_hex(s, &(x), sizeof(x)))	\
-		return TRACE_TYPE_PARTIAL_LINE;		\
-} while (0)
+#define SEQ_PUT_FIELD(s, x)				\
+	trace_seq_putmem(s, &(x), sizeof(x))
+
+#define SEQ_PUT_HEX_FIELD(s, x)				\
+	trace_seq_putmem_hex(s, &(x), sizeof(x))
 
 #endif
 
-- 
2.1.1

[for-next][PATCH 08/18] blktrace/tracing: Use trace_seq_has_overflowed() helper function

[Steven Rostedt]

[-- Attachment #1: 0008-blktrace-tracing-Use-trace_seq_has_overflowed-helper.patch --]
[-- Type: text/plain, Size: 10222 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Checking the return code of every trace_seq_printf() operation and having
to return early if it overflowed makes the code messy.

Using the new trace_seq_has_overflowed() and trace_handle_return() functions
allows us to clean up the code.

In the future, trace_seq_printf() and friends will be turning into void
functions and not returning a value. The trace_seq_has_overflowed() is to
be used instead. This cleanup allows that change to take place.

Cc: Jens Axboe <axboe@fb.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/blktrace.c | 148 +++++++++++++++++++++---------------------------
 1 file changed, 66 insertions(+), 82 deletions(-)

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index c1bd4ada2a04..11b9cb36092b 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1142,9 +1142,9 @@ static void get_pdu_remap(const struct trace_entry *ent,
 	r->sector_from = be64_to_cpu(sector_from);
 }
 
-typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
+typedef void (blk_log_action_t) (struct trace_iterator *iter, const char *act);
 
-static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
+static void blk_log_action_classic(struct trace_iterator *iter, const char *act)
 {
 	char rwbs[RWBS_LEN];
 	unsigned long long ts  = iter->ts;
@@ -1154,33 +1154,33 @@ static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
 
 	fill_rwbs(rwbs, t);
 
-	return trace_seq_printf(&iter->seq,
-				"%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
-				MAJOR(t->device), MINOR(t->device), iter->cpu,
-				secs, nsec_rem, iter->ent->pid, act, rwbs);
+	trace_seq_printf(&iter->seq,
+			 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
+			 MAJOR(t->device), MINOR(t->device), iter->cpu,
+			 secs, nsec_rem, iter->ent->pid, act, rwbs);
 }
 
-static int blk_log_action(struct trace_iterator *iter, const char *act)
+static void blk_log_action(struct trace_iterator *iter, const char *act)
 {
 	char rwbs[RWBS_LEN];
 	const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
 
 	fill_rwbs(rwbs, t);
-	return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
-				MAJOR(t->device), MINOR(t->device), act, rwbs);
+	trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
+			 MAJOR(t->device), MINOR(t->device), act, rwbs);
 }
 
-static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
 {
 	const unsigned char *pdu_buf;
 	int pdu_len;
-	int i, end, ret;
+	int i, end;
 
 	pdu_buf = pdu_start(ent);
 	pdu_len = te_blk_io_trace(ent)->pdu_len;
 
 	if (!pdu_len)
-		return 1;
+		return;
 
 	/* find the last zero that needs to be printed */
 	for (end = pdu_len - 1; end >= 0; end--)
@@ -1188,119 +1188,107 @@ static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
 			break;
 	end++;
 
-	if (!trace_seq_putc(s, '('))
-		return 0;
+	trace_seq_putc(s, '(');
 
 	for (i = 0; i < pdu_len; i++) {
 
-		ret = trace_seq_printf(s, "%s%02x",
-				       i == 0 ? "" : " ", pdu_buf[i]);
-		if (!ret)
-			return ret;
+		trace_seq_printf(s, "%s%02x",
+				 i == 0 ? "" : " ", pdu_buf[i]);
 
 		/*
 		 * stop when the rest is just zeroes and indicate so
 		 * with a ".." appended
 		 */
-		if (i == end && end != pdu_len - 1)
-			return trace_seq_puts(s, " ..) ");
+		if (i == end && end != pdu_len - 1) {
+			trace_seq_puts(s, " ..) ");
+			return;
+		}
 	}
 
-	return trace_seq_puts(s, ") ");
+	trace_seq_puts(s, ") ");
 }
 
-static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
 	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
-		int ret;
-
-		ret = trace_seq_printf(s, "%u ", t_bytes(ent));
-		if (!ret)
-			return 0;
-		ret = blk_log_dump_pdu(s, ent);
-		if (!ret)
-			return 0;
-		return trace_seq_printf(s, "[%s]\n", cmd);
+		trace_seq_printf(s, "%u ", t_bytes(ent));
+		blk_log_dump_pdu(s, ent);
+		trace_seq_printf(s, "[%s]\n", cmd);
 	} else {
 		if (t_sec(ent))
-			return trace_seq_printf(s, "%llu + %u [%s]\n",
+			trace_seq_printf(s, "%llu + %u [%s]\n",
 						t_sector(ent), t_sec(ent), cmd);
-		return trace_seq_printf(s, "[%s]\n", cmd);
+		else
+			trace_seq_printf(s, "[%s]\n", cmd);
 	}
 }
 
-static int blk_log_with_error(struct trace_seq *s,
+static void blk_log_with_error(struct trace_seq *s,
 			      const struct trace_entry *ent)
 {
 	if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
-		int ret;
-
-		ret = blk_log_dump_pdu(s, ent);
-		if (ret)
-			return trace_seq_printf(s, "[%d]\n", t_error(ent));
-		return 0;
+		blk_log_dump_pdu(s, ent);
+		trace_seq_printf(s, "[%d]\n", t_error(ent));
 	} else {
 		if (t_sec(ent))
-			return trace_seq_printf(s, "%llu + %u [%d]\n",
-						t_sector(ent),
-						t_sec(ent), t_error(ent));
-		return trace_seq_printf(s, "%llu [%d]\n",
-					t_sector(ent), t_error(ent));
+			trace_seq_printf(s, "%llu + %u [%d]\n",
+					 t_sector(ent),
+					 t_sec(ent), t_error(ent));
+		else
+			trace_seq_printf(s, "%llu [%d]\n",
+					 t_sector(ent), t_error(ent));
 	}
 }
 
-static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
 {
 	struct blk_io_trace_remap r = { .device_from = 0, };
 
 	get_pdu_remap(ent, &r);
-	return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
-				t_sector(ent), t_sec(ent),
-				MAJOR(r.device_from), MINOR(r.device_from),
-				(unsigned long long)r.sector_from);
+	trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
+			 t_sector(ent), t_sec(ent),
+			 MAJOR(r.device_from), MINOR(r.device_from),
+			 (unsigned long long)r.sector_from);
 }
 
-static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
-	return trace_seq_printf(s, "[%s]\n", cmd);
+	trace_seq_printf(s, "[%s]\n", cmd);
 }
 
-static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
-	return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
+	trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
 }
 
-static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
 {
 	char cmd[TASK_COMM_LEN];
 
 	trace_find_cmdline(ent->pid, cmd);
 
-	return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
-				get_pdu_int(ent), cmd);
+	trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
+			 get_pdu_int(ent), cmd);
 }
 
-static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
+static void blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
 {
-	int ret;
 	const struct blk_io_trace *t = te_blk_io_trace(ent);
 
-	ret = trace_seq_putmem(s, t + 1, t->pdu_len);
-	if (ret)
-		return trace_seq_putc(s, '\n');
-	return ret;
+	trace_seq_putmem(s, t + 1, t->pdu_len);
+	trace_seq_putc(s, '\n');
 }
 
 /*
@@ -1339,7 +1327,7 @@ static void blk_tracer_reset(struct trace_array *tr)
 
 static const struct {
 	const char *act[2];
-	int	   (*print)(struct trace_seq *s, const struct trace_entry *ent);
+	void	   (*print)(struct trace_seq *s, const struct trace_entry *ent);
 } what2act[] = {
 	[__BLK_TA_QUEUE]	= {{  "Q", "queue" },	   blk_log_generic },
 	[__BLK_TA_BACKMERGE]	= {{  "M", "backmerge" },  blk_log_generic },
@@ -1364,7 +1352,6 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
 	struct trace_seq *s = &iter->seq;
 	const struct blk_io_trace *t;
 	u16 what;
-	int ret;
 	bool long_act;
 	blk_log_action_t *log_action;
 
@@ -1374,21 +1361,18 @@ static enum print_line_t print_one_line(struct trace_iterator *iter,
 	log_action = classic ? &blk_log_action_classic : &blk_log_action;
 
 	if (t->action == BLK_TN_MESSAGE) {
-		ret = log_action(iter, long_act ? "message" : "m");
-		if (ret)
-			ret = blk_log_msg(s, iter->ent);
-		goto out;
+		log_action(iter, long_act ? "message" : "m");
+		blk_log_msg(s, iter->ent);
 	}
 
 	if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
-		ret = trace_seq_printf(s, "Unknown action %x\n", what);
+		trace_seq_printf(s, "Unknown action %x\n", what);
 	else {
-		ret = log_action(iter, what2act[what].act[long_act]);
-		if (ret)
-			ret = what2act[what].print(s, iter->ent);
+		log_action(iter, what2act[what].act[long_act]);
+		what2act[what].print(s, iter->ent);
 	}
-out:
-	return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+
+	return trace_handle_return(s);
 }
 
 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
@@ -1397,7 +1381,7 @@ static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
 	return print_one_line(iter, false);
 }
 
-static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
+static void blk_trace_synthesize_old_trace(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
@@ -1407,18 +1391,18 @@ static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
 		.time     = iter->ts,
 	};
 
-	if (!trace_seq_putmem(s, &old, offset))
-		return 0;
-	return trace_seq_putmem(s, &t->sector,
-				sizeof(old) - offset + t->pdu_len);
+	trace_seq_putmem(s, &old, offset);
+	trace_seq_putmem(s, &t->sector,
+			 sizeof(old) - offset + t->pdu_len);
 }
 
 static enum print_line_t
 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
 			     struct trace_event *event)
 {
-	return blk_trace_synthesize_old_trace(iter) ?
-			TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+	blk_trace_synthesize_old_trace(iter);
+
+	return trace_handle_return(&iter->seq);
 }
 
 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
-- 
2.1.1

[for-next][PATCH 09/18] ring-buffer: Remove check of trace_seq_{puts,printf}() return values

[Steven Rostedt]

[-- Attachment #1: 0009-ring-buffer-Remove-check-of-trace_seq_-puts-printf-r.patch --]
[-- Type: text/plain, Size: 4068 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Remove checking the return value of all trace_seq_puts(). It was wrong
anyway as only the last return value mattered. But as the trace_seq_puts()
is going to be a void function in the future, we should not be checking
the return value of it anyway.

Just return !trace_seq_has_overflowed() instead.

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 75 ++++++++++++++++++++++------------------------
 1 file changed, 36 insertions(+), 39 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2d75c94ae87d..a28bdd17c853 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -34,21 +34,19 @@ static void update_pages_handler(struct work_struct *work);
  */
 int ring_buffer_print_entry_header(struct trace_seq *s)
 {
-	int ret;
-
-	ret = trace_seq_puts(s, "# compressed entry header\n");
-	ret = trace_seq_puts(s, "\ttype_len    :    5 bits\n");
-	ret = trace_seq_puts(s, "\ttime_delta  :   27 bits\n");
-	ret = trace_seq_puts(s, "\tarray       :   32 bits\n");
-	ret = trace_seq_putc(s, '\n');
-	ret = trace_seq_printf(s, "\tpadding     : type == %d\n",
-			       RINGBUF_TYPE_PADDING);
-	ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
-			       RINGBUF_TYPE_TIME_EXTEND);
-	ret = trace_seq_printf(s, "\tdata max type_len  == %d\n",
-			       RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+	trace_seq_puts(s, "# compressed entry header\n");
+	trace_seq_puts(s, "\ttype_len    :    5 bits\n");
+	trace_seq_puts(s, "\ttime_delta  :   27 bits\n");
+	trace_seq_puts(s, "\tarray       :   32 bits\n");
+	trace_seq_putc(s, '\n');
+	trace_seq_printf(s, "\tpadding     : type == %d\n",
+			 RINGBUF_TYPE_PADDING);
+	trace_seq_printf(s, "\ttime_extend : type == %d\n",
+			 RINGBUF_TYPE_TIME_EXTEND);
+	trace_seq_printf(s, "\tdata max type_len  == %d\n",
+			 RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
 
-	return ret;
+	return !trace_seq_has_overflowed(s);
 }
 
 /*
@@ -419,32 +417,31 @@ static inline int test_time_stamp(u64 delta)
 int ring_buffer_print_page_header(struct trace_seq *s)
 {
 	struct buffer_data_page field;
-	int ret;
-
-	ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
-			       "offset:0;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)sizeof(field.time_stamp),
-			       (unsigned int)is_signed_type(u64));
-
-	ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
-			       "offset:%u;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)offsetof(typeof(field), commit),
-			       (unsigned int)sizeof(field.commit),
-			       (unsigned int)is_signed_type(long));
-
-	ret = trace_seq_printf(s, "\tfield: int overwrite;\t"
-			       "offset:%u;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)offsetof(typeof(field), commit),
-			       1,
-			       (unsigned int)is_signed_type(long));
-
-	ret = trace_seq_printf(s, "\tfield: char data;\t"
-			       "offset:%u;\tsize:%u;\tsigned:%u;\n",
-			       (unsigned int)offsetof(typeof(field), data),
-			       (unsigned int)BUF_PAGE_SIZE,
-			       (unsigned int)is_signed_type(char));
 
-	return ret;
+	trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+			 "offset:0;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)sizeof(field.time_stamp),
+			 (unsigned int)is_signed_type(u64));
+
+	trace_seq_printf(s, "\tfield: local_t commit;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), commit),
+			 (unsigned int)sizeof(field.commit),
+			 (unsigned int)is_signed_type(long));
+
+	trace_seq_printf(s, "\tfield: int overwrite;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), commit),
+			 1,
+			 (unsigned int)is_signed_type(long));
+
+	trace_seq_printf(s, "\tfield: char data;\t"
+			 "offset:%u;\tsize:%u;\tsigned:%u;\n",
+			 (unsigned int)offsetof(typeof(field), data),
+			 (unsigned int)BUF_PAGE_SIZE,
+			 (unsigned int)is_signed_type(char));
+
+	return !trace_seq_has_overflowed(s);
 }
 
 struct rb_irq_work {
-- 
2.1.1

[for-next][PATCH 10/18] tracing: Have branch tracer use trace_handle_return() helper function

[Steven Rostedt]

[-- Attachment #1: 0010-tracing-Have-branch-tracer-use-trace_handle_return-h.patch --]
[-- Type: text/plain, Size: 1328 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The branch tracer should not be checking the trace_seq_printf() return value
as that will soon be void. There's a new trace_handle_return() helper function
that will return TRACE_TYPE_PARTIAL_LINE if the trace_seq overflowed
and TRACE_TYPE_HANDLED otherwise.

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_branch.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index a3916f68a1c7..7d6e2afde669 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -151,14 +151,13 @@ static enum print_line_t trace_branch_print(struct trace_iterator *iter,
 
 	trace_assign_type(field, iter->ent);
 
-	if (trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
-			     field->correct ? "  ok  " : " MISS ",
-			     field->func,
-			     field->file,
-			     field->line))
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_printf(&iter->seq, "[%s] %s:%s:%d\n",
+			 field->correct ? "  ok  " : " MISS ",
+			 field->func,
+			 field->file,
+			 field->line);
+
+	return trace_handle_return(&iter->seq);
 }
 
 static void branch_print_header(struct seq_file *s)
-- 
2.1.1

[for-next][PATCH 11/18] tracing: Have function_graph use trace_seq_has_overflowed()

[Steven Rostedt]

[-- Attachment #1: 0011-tracing-Have-function_graph-use-trace_seq_has_overfl.patch --]
[-- Type: text/plain, Size: 19665 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Instead of doing individual checks all over the place that makes the code
very messy. Just check trace_seq_has_overflowed() at the end or in
strategic places.

This makes the code much cleaner and also helps with getting closer
to removing the return values of trace_seq_printf() and friends.

Link: http://lkml.kernel.org/r/20141114011410.987913836@goodmis.org

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.h                 |   2 +-
 kernel/trace/trace_functions_graph.c | 382 +++++++++++------------------------
 2 files changed, 118 insertions(+), 266 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 19418221b302..c3a37e55ec8b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -726,7 +726,7 @@ extern unsigned long trace_flags;
 extern enum print_line_t
 print_graph_function_flags(struct trace_iterator *iter, u32 flags);
 extern void print_graph_headers_flags(struct seq_file *s, u32 flags);
-extern enum print_line_t
+extern void
 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
 extern void graph_trace_open(struct trace_iterator *iter);
 extern void graph_trace_close(struct trace_iterator *iter);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 55bdf9d7f714..100288d10e1f 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -107,7 +107,7 @@ enum {
 	FLAGS_FILL_END   = 3 << TRACE_GRAPH_PRINT_FILL_SHIFT,
 };
 
-static enum print_line_t
+static void
 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 		     u32 flags);
 
@@ -483,33 +483,24 @@ static int graph_trace_update_thresh(struct trace_array *tr)
 
 static int max_bytes_for_cpu;
 
-static enum print_line_t
-print_graph_cpu(struct trace_seq *s, int cpu)
+static void print_graph_cpu(struct trace_seq *s, int cpu)
 {
-	int ret;
-
 	/*
 	 * Start with a space character - to make it stand out
 	 * to the right a bit when trace output is pasted into
 	 * email:
 	 */
-	ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 }
 
 #define TRACE_GRAPH_PROCINFO_LENGTH	14
 
-static enum print_line_t
-print_graph_proc(struct trace_seq *s, pid_t pid)
+static void print_graph_proc(struct trace_seq *s, pid_t pid)
 {
 	char comm[TASK_COMM_LEN];
 	/* sign + log10(MAX_INT) + '\0' */
 	char pid_str[11];
 	int spaces = 0;
-	int ret;
 	int len;
 	int i;
 
@@ -524,56 +515,43 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
 		spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 
 	/* First spaces to align center */
-	for (i = 0; i < spaces / 2; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < spaces / 2; i++)
+		trace_seq_putc(s, ' ');
 
-	ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s-%s", comm, pid_str);
 
 	/* Last spaces to align center */
-	for (i = 0; i < spaces - (spaces / 2); i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
-	return TRACE_TYPE_HANDLED;
+	for (i = 0; i < spaces - (spaces / 2); i++)
+		trace_seq_putc(s, ' ');
 }
 
 
-static enum print_line_t
-print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
+static void print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 {
-	if (!trace_seq_putc(s, ' '))
-		return 0;
-
-	return trace_print_lat_fmt(s, entry);
+	trace_seq_putc(s, ' ');
+	trace_print_lat_fmt(s, entry);
 }
 
 /* If the pid changed since the last trace, output this event */
-static enum print_line_t
+static void
 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 {
 	pid_t prev_pid;
 	pid_t *last_pid;
-	int ret;
 
 	if (!data)
-		return TRACE_TYPE_HANDLED;
+		return;
 
 	last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 
 	if (*last_pid == pid)
-		return TRACE_TYPE_HANDLED;
+		return;
 
 	prev_pid = *last_pid;
 	*last_pid = pid;
 
 	if (prev_pid == -1)
-		return TRACE_TYPE_HANDLED;
+		return;
 /*
  * Context-switch trace line:
 
@@ -582,33 +560,12 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
  ------------------------------------------
 
  */
-	ret = trace_seq_puts(s,
-		" ------------------------------------------\n");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_cpu(s, cpu);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_proc(s, prev_pid);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_puts(s, " => ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_proc(s, pid);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_seq_puts(s,
-		"\n ------------------------------------------\n\n");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_seq_puts(s, " ------------------------------------------\n");
+	print_graph_cpu(s, cpu);
+	print_graph_proc(s, prev_pid);
+	trace_seq_puts(s, " => ");
+	print_graph_proc(s, pid);
+	trace_seq_puts(s, "\n ------------------------------------------\n\n");
 }
 
 static struct ftrace_graph_ret_entry *
@@ -682,103 +639,74 @@ get_return_for_leaf(struct trace_iterator *iter,
 	return next;
 }
 
-static int print_graph_abs_time(u64 t, struct trace_seq *s)
+static void print_graph_abs_time(u64 t, struct trace_seq *s)
 {
 	unsigned long usecs_rem;
 
 	usecs_rem = do_div(t, NSEC_PER_SEC);
 	usecs_rem /= 1000;
 
-	return trace_seq_printf(s, "%5lu.%06lu |  ",
-			(unsigned long)t, usecs_rem);
+	trace_seq_printf(s, "%5lu.%06lu |  ",
+			 (unsigned long)t, usecs_rem);
 }
 
-static enum print_line_t
+static void
 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 		enum trace_type type, int cpu, pid_t pid, u32 flags)
 {
-	int ret;
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *ent = iter->ent;
 
 	if (addr < (unsigned long)__irqentry_text_start ||
 		addr >= (unsigned long)__irqentry_text_end)
-		return TRACE_TYPE_UNHANDLED;
+		return;
 
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 		/* Absolute time */
-		if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
-			ret = print_graph_abs_time(iter->ts, s);
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+			print_graph_abs_time(iter->ts, s);
 
 		/* Cpu */
-		if (flags & TRACE_GRAPH_PRINT_CPU) {
-			ret = print_graph_cpu(s, cpu);
-			if (ret == TRACE_TYPE_PARTIAL_LINE)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (flags & TRACE_GRAPH_PRINT_CPU)
+			print_graph_cpu(s, cpu);
 
 		/* Proc */
 		if (flags & TRACE_GRAPH_PRINT_PROC) {
-			ret = print_graph_proc(s, pid);
-			if (ret == TRACE_TYPE_PARTIAL_LINE)
-				return TRACE_TYPE_PARTIAL_LINE;
-			ret = trace_seq_puts(s, " | ");
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
+			print_graph_proc(s, pid);
+			trace_seq_puts(s, " | ");
 		}
 
 		/* Latency format */
-		if (trace_flags & TRACE_ITER_LATENCY_FMT) {
-			ret = print_graph_lat_fmt(s, ent);
-			if (ret == TRACE_TYPE_PARTIAL_LINE)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
-
+		if (trace_flags & TRACE_ITER_LATENCY_FMT)
+			print_graph_lat_fmt(s, ent);
 	}
 
 	/* No overhead */
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_START);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	print_graph_duration(0, s, flags | FLAGS_FILL_START);
 
 	if (type == TRACE_GRAPH_ENT)
-		ret = trace_seq_puts(s, "==========>");
+		trace_seq_puts(s, "==========>");
 	else
-		ret = trace_seq_puts(s, "<==========");
-
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_END);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+		trace_seq_puts(s, "<==========");
 
-	ret = trace_seq_putc(s, '\n');
-
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-	return TRACE_TYPE_HANDLED;
+	print_graph_duration(0, s, flags | FLAGS_FILL_END);
+	trace_seq_putc(s, '\n');
 }
 
-enum print_line_t
+void
 trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
 	unsigned long nsecs_rem = do_div(duration, 1000);
 	/* log10(ULONG_MAX) + '\0' */
 	char usecs_str[21];
 	char nsecs_str[5];
-	int ret, len;
+	int len;
 	int i;
 
 	sprintf(usecs_str, "%lu", (unsigned long) duration);
 
 	/* Print msecs */
-	ret = trace_seq_printf(s, "%s", usecs_str);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s", usecs_str);
 
 	len = strlen(usecs_str);
 
@@ -787,79 +715,63 @@ trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 		size_t slen = min_t(size_t, sizeof(nsecs_str), 8UL - len);
 
 		snprintf(nsecs_str, slen, "%03lu", nsecs_rem);
-		ret = trace_seq_printf(s, ".%s", nsecs_str);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_printf(s, ".%s", nsecs_str);
 		len += strlen(nsecs_str);
 	}
 
-	ret = trace_seq_puts(s, " us ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, " us ");
 
 	/* Print remaining spaces to fit the row's width */
-	for (i = len; i < 7; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
-	return TRACE_TYPE_HANDLED;
+	for (i = len; i < 7; i++)
+		trace_seq_putc(s, ' ');
 }
 
-static enum print_line_t
+static void
 print_graph_duration(unsigned long long duration, struct trace_seq *s,
 		     u32 flags)
 {
-	int ret = -1;
+	bool duration_printed = false;
 
 	if (!(flags & TRACE_GRAPH_PRINT_DURATION) ||
 	    !(trace_flags & TRACE_ITER_CONTEXT_INFO))
-			return TRACE_TYPE_HANDLED;
+		return;
 
 	/* No real adata, just filling the column with spaces */
 	switch (flags & TRACE_GRAPH_PRINT_FILL_MASK) {
 	case FLAGS_FILL_FULL:
-		ret = trace_seq_puts(s, "              |  ");
-		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_puts(s, "              |  ");
+		return;
 	case FLAGS_FILL_START:
-		ret = trace_seq_puts(s, "  ");
-		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_puts(s, "  ");
+		return;
 	case FLAGS_FILL_END:
-		ret = trace_seq_puts(s, " |");
-		return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_puts(s, " |");
+		return;
 	}
 
 	/* Signal a overhead of time execution to the output */
 	if (flags & TRACE_GRAPH_PRINT_OVERHEAD) {
 		/* Duration exceeded 100 usecs */
-		if (duration > 100000ULL)
-			ret = trace_seq_puts(s, "! ");
+		if (duration > 100000ULL) {
+			trace_seq_puts(s, "! ");
+			duration_printed = true;
+
 		/* Duration exceeded 10 usecs */
-		else if (duration > 10000ULL)
-			ret = trace_seq_puts(s, "+ ");
+		} else if (duration > 10000ULL) {
+			trace_seq_puts(s, "+ ");
+			duration_printed = true;
+		}
 	}
 
 	/*
-	 * The -1 means we either did not exceed the duration tresholds
-	 * or we dont want to print out the overhead. Either way we need
-	 * to fill out the space.
+	 * If we did not exceed the duration tresholds or we dont want
+	 * to print out the overhead. Either way we need to fill out the space.
 	 */
-	if (ret == -1)
-		ret = trace_seq_puts(s, "  ");
-
-	/* Catching here any failure happenned above */
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	ret = trace_print_graph_duration(duration, s);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	if (!duration_printed)
+		trace_seq_puts(s, "  ");
 
-	ret = trace_seq_puts(s, "|  ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return TRACE_TYPE_HANDLED;
+	trace_print_graph_duration(duration, s);
+	trace_seq_puts(s, "|  ");
 }
 
 /* Case of a leaf function on its call entry */
@@ -873,7 +785,6 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 	struct ftrace_graph_ret *graph_ret;
 	struct ftrace_graph_ent *call;
 	unsigned long long duration;
-	int ret;
 	int i;
 
 	graph_ret = &ret_entry->ret;
@@ -899,22 +810,15 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 	}
 
 	/* Overhead and duration */
-	ret = print_graph_duration(duration, s, flags);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_duration(duration, s, flags);
 
 	/* Function */
-	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
 
-	ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%ps();\n", (void *)call->func);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -924,7 +828,6 @@ print_graph_entry_nested(struct trace_iterator *iter,
 {
 	struct ftrace_graph_ent *call = &entry->graph_ent;
 	struct fgraph_data *data = iter->private;
-	int ret;
 	int i;
 
 	if (data) {
@@ -940,19 +843,15 @@ print_graph_entry_nested(struct trace_iterator *iter,
 	}
 
 	/* No time */
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 
 	/* Function */
-	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
+
+	trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 
-	ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
-	if (!ret)
+	if (trace_seq_has_overflowed(s))
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	/*
@@ -962,62 +861,43 @@ print_graph_entry_nested(struct trace_iterator *iter,
 	return TRACE_TYPE_NO_CONSUME;
 }
 
-static enum print_line_t
+static void
 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 		     int type, unsigned long addr, u32 flags)
 {
 	struct fgraph_data *data = iter->private;
 	struct trace_entry *ent = iter->ent;
 	int cpu = iter->cpu;
-	int ret;
 
 	/* Pid */
-	if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	verif_pid(s, ent->pid, cpu, data);
 
-	if (type) {
+	if (type)
 		/* Interrupt */
-		ret = print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+		print_graph_irq(iter, addr, type, cpu, ent->pid, flags);
 
 	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
-		return 0;
+		return;
 
 	/* Absolute time */
-	if (flags & TRACE_GRAPH_PRINT_ABS_TIME) {
-		ret = print_graph_abs_time(iter->ts, s);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (flags & TRACE_GRAPH_PRINT_ABS_TIME)
+		print_graph_abs_time(iter->ts, s);
 
 	/* Cpu */
-	if (flags & TRACE_GRAPH_PRINT_CPU) {
-		ret = print_graph_cpu(s, cpu);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (flags & TRACE_GRAPH_PRINT_CPU)
+		print_graph_cpu(s, cpu);
 
 	/* Proc */
 	if (flags & TRACE_GRAPH_PRINT_PROC) {
-		ret = print_graph_proc(s, ent->pid);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-
-		ret = trace_seq_puts(s, " | ");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		print_graph_proc(s, ent->pid);
+		trace_seq_puts(s, " | ");
 	}
 
 	/* Latency format */
-	if (trace_flags & TRACE_ITER_LATENCY_FMT) {
-		ret = print_graph_lat_fmt(s, ent);
-		if (ret == TRACE_TYPE_PARTIAL_LINE)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (trace_flags & TRACE_ITER_LATENCY_FMT)
+		print_graph_lat_fmt(s, ent);
 
-	return 0;
+	return;
 }
 
 /*
@@ -1135,8 +1015,7 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 	if (check_irq_entry(iter, flags, call->func, call->depth))
 		return TRACE_TYPE_HANDLED;
 
-	if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags))
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func, flags);
 
 	leaf_ret = get_return_for_leaf(iter, field);
 	if (leaf_ret)
@@ -1169,7 +1048,6 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	pid_t pid = ent->pid;
 	int cpu = iter->cpu;
 	int func_match = 1;
-	int ret;
 	int i;
 
 	if (check_irq_return(iter, flags, trace->depth))
@@ -1195,20 +1073,14 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 		}
 	}
 
-	if (print_graph_prologue(iter, s, 0, 0, flags))
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_prologue(iter, s, 0, 0, flags);
 
 	/* Overhead and duration */
-	ret = print_graph_duration(duration, s, flags);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_duration(duration, s, flags);
 
 	/* Closing brace */
-	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
-		ret = trace_seq_putc(s, ' ');
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++)
+		trace_seq_putc(s, ' ');
 
 	/*
 	 * If the return function does not have a matching entry,
@@ -1217,30 +1089,20 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	 * belongs to, write out the function name. Always do
 	 * that if the funcgraph-tail option is enabled.
 	 */
-	if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL)) {
-		ret = trace_seq_puts(s, "}\n");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	} else {
-		ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (func_match && !(flags & TRACE_GRAPH_PRINT_TAIL))
+		trace_seq_puts(s, "}\n");
+	else
+		trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
 
 	/* Overrun */
-	if (flags & TRACE_GRAPH_PRINT_OVERRUN) {
-		ret = trace_seq_printf(s, " (Overruns: %lu)\n",
-					trace->overrun);
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
-	}
+	if (flags & TRACE_GRAPH_PRINT_OVERRUN)
+		trace_seq_printf(s, " (Overruns: %lu)\n",
+				 trace->overrun);
 
-	ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
-			      cpu, pid, flags);
-	if (ret == TRACE_TYPE_PARTIAL_LINE)
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,
+			cpu, pid, flags);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -1257,26 +1119,18 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 	if (data)
 		depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
 
-	if (print_graph_prologue(iter, s, 0, 0, flags))
-		return TRACE_TYPE_PARTIAL_LINE;
+	print_graph_prologue(iter, s, 0, 0, flags);
 
 	/* No time */
-	ret = print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
-	if (ret != TRACE_TYPE_HANDLED)
-		return ret;
+	print_graph_duration(0, s, flags | FLAGS_FILL_FULL);
 
 	/* Indentation */
 	if (depth > 0)
-		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
-			ret = trace_seq_putc(s, ' ');
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++)
+			trace_seq_putc(s, ' ');
 
 	/* The comment */
-	ret = trace_seq_puts(s, "/* ");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, "/* ");
 
 	switch (iter->ent->type) {
 	case TRACE_BPRINT:
@@ -1305,11 +1159,9 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent,
 		s->len--;
 	}
 
-	ret = trace_seq_puts(s, " */\n");
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_puts(s, " */\n");
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 
-- 
2.1.1

[for-next][PATCH 12/18] kprobes/tracing: Use trace_seq_has_overflowed() for overflow checks

[Steven Rostedt]

[-- Attachment #1: 0012-kprobes-tracing-Use-trace_seq_has_overflowed-for-ove.patch --]
[-- Type: text/plain, Size: 3020 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Instead of checking the return value of trace_seq_printf() and friends
for overflowing of the buffer, use the trace_seq_has_overflowed() helper
function.

This cleans up the code quite a bit and also takes us a step closer to
changing the return values of trace_seq_printf() and friends to void.

Link: http://lkml.kernel.org/r/20141114011411.181812785@goodmis.org

Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c | 42 ++++++++++++++++--------------------------
 1 file changed, 16 insertions(+), 26 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index ef7e7f16ed1a..5edb518be345 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1024,27 +1024,22 @@ print_kprobe_event(struct trace_iterator *iter, int flags,
 	field = (struct kprobe_trace_entry_head *)iter->ent;
 	tp = container_of(event, struct trace_probe, call.event);
 
-	if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
-		goto partial;
+	trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
 
 	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
-		goto partial;
+		goto out;
 
-	if (!trace_seq_putc(s, ')'))
-		goto partial;
+	trace_seq_putc(s, ')');
 
 	data = (u8 *)&field[1];
 	for (i = 0; i < tp->nr_args; i++)
 		if (!tp->args[i].type->print(s, tp->args[i].name,
 					     data + tp->args[i].offset, field))
-			goto partial;
-
-	if (!trace_seq_putc(s, '\n'))
-		goto partial;
+			goto out;
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_putc(s, '\n');
+ out:
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -1060,33 +1055,28 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,
 	field = (struct kretprobe_trace_entry_head *)iter->ent;
 	tp = container_of(event, struct trace_probe, call.event);
 
-	if (!trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call)))
-		goto partial;
+	trace_seq_printf(s, "%s: (", ftrace_event_name(&tp->call));
 
 	if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
-		goto partial;
+		goto out;
 
-	if (!trace_seq_puts(s, " <- "))
-		goto partial;
+	trace_seq_puts(s, " <- ");
 
 	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
-		goto partial;
+		goto out;
 
-	if (!trace_seq_putc(s, ')'))
-		goto partial;
+	trace_seq_putc(s, ')');
 
 	data = (u8 *)&field[1];
 	for (i = 0; i < tp->nr_args; i++)
 		if (!tp->args[i].type->print(s, tp->args[i].name,
 					     data + tp->args[i].offset, field))
-			goto partial;
+			goto out;
 
-	if (!trace_seq_putc(s, '\n'))
-		goto partial;
+	trace_seq_putc(s, '\n');
 
-	return TRACE_TYPE_HANDLED;
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+ out:
+	return trace_handle_return(s);
 }
 
 
-- 
2.1.1

[for-next][PATCH 13/18] tracing: Do not check return values of trace_seq_p*() for mmio tracer

[Steven Rostedt]

[-- Attachment #1: 0013-tracing-Do-not-check-return-values-of-trace_seq_p-fo.patch --]
[-- Type: text/plain, Size: 5608 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The return values for trace_seq_printf() and friends are going to be
removed and they will become void functions. The mmio tracer checked
their return and even did so incorrectly.

Some of the funtions which returned the values were never checked
themselves. Removing all the checks simplifies the code.

Use trace_seq_has_overflowed() and trace_handle_return() where
necessary instead.

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_mmiotrace.c | 52 +++++++++++++++++-------------------------
 1 file changed, 21 insertions(+), 31 deletions(-)

diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index 0abd9b863474..7a9ba62e9fef 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -59,17 +59,15 @@ static void mmio_trace_start(struct trace_array *tr)
 	mmio_reset_data(tr);
 }
 
-static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
+static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
 {
-	int ret = 0;
 	int i;
 	resource_size_t start, end;
 	const struct pci_driver *drv = pci_dev_driver(dev);
 
-	/* XXX: incomplete checks for trace_seq_printf() return value */
-	ret += trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
-				dev->bus->number, dev->devfn,
-				dev->vendor, dev->device, dev->irq);
+	trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
+			 dev->bus->number, dev->devfn,
+			 dev->vendor, dev->device, dev->irq);
 	/*
 	 * XXX: is pci_resource_to_user() appropriate, since we are
 	 * supposed to interpret the __ioremap() phys_addr argument based on
@@ -77,21 +75,20 @@ static int mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
 	 */
 	for (i = 0; i < 7; i++) {
 		pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
-		ret += trace_seq_printf(s, " %llx",
+		trace_seq_printf(s, " %llx",
 			(unsigned long long)(start |
 			(dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
 	}
 	for (i = 0; i < 7; i++) {
 		pci_resource_to_user(dev, i, &dev->resource[i], &start, &end);
-		ret += trace_seq_printf(s, " %llx",
+		trace_seq_printf(s, " %llx",
 			dev->resource[i].start < dev->resource[i].end ?
 			(unsigned long long)(end - start) + 1 : 0);
 	}
 	if (drv)
-		ret += trace_seq_printf(s, " %s\n", drv->name);
+		trace_seq_printf(s, " %s\n", drv->name);
 	else
-		ret += trace_seq_puts(s, " \n");
-	return ret;
+		trace_seq_puts(s, " \n");
 }
 
 static void destroy_header_iter(struct header_iter *hiter)
@@ -179,28 +176,27 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
-	int ret = 1;
 
 	trace_assign_type(field, entry);
 	rw = &field->rw;
 
 	switch (rw->opcode) {
 	case MMIO_READ:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 			rw->width, secs, usec_rem, rw->map_id,
 			(unsigned long long)rw->phys,
 			rw->value, rw->pc, 0);
 		break;
 	case MMIO_WRITE:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 			rw->width, secs, usec_rem, rw->map_id,
 			(unsigned long long)rw->phys,
 			rw->value, rw->pc, 0);
 		break;
 	case MMIO_UNKNOWN_OP:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 			"%02lx 0x%lx %d\n",
 			secs, usec_rem, rw->map_id,
@@ -209,12 +205,11 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 			(rw->value >> 0) & 0xff, rw->pc, 0);
 		break;
 	default:
-		ret = trace_seq_puts(s, "rw what?\n");
+		trace_seq_puts(s, "rw what?\n");
 		break;
 	}
-	if (ret)
-		return TRACE_TYPE_HANDLED;
-	return TRACE_TYPE_PARTIAL_LINE;
+
+	return trace_handle_return(s);
 }
 
 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
@@ -226,31 +221,29 @@ static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
-	int ret;
 
 	trace_assign_type(field, entry);
 	m = &field->map;
 
 	switch (m->opcode) {
 	case MMIO_PROBE:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 			secs, usec_rem, m->map_id,
 			(unsigned long long)m->phys, m->virt, m->len,
 			0UL, 0);
 		break;
 	case MMIO_UNPROBE:
-		ret = trace_seq_printf(s,
+		trace_seq_printf(s,
 			"UNMAP %u.%06lu %d 0x%lx %d\n",
 			secs, usec_rem, m->map_id, 0UL, 0);
 		break;
 	default:
-		ret = trace_seq_puts(s, "map what?\n");
+		trace_seq_puts(s, "map what?\n");
 		break;
 	}
-	if (ret)
-		return TRACE_TYPE_HANDLED;
-	return TRACE_TYPE_PARTIAL_LINE;
+
+	return trace_handle_return(s);
 }
 
 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
@@ -262,14 +255,11 @@ static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 	unsigned long long t	= ns2usecs(iter->ts);
 	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
-	int ret;
 
 	/* The trailing newline must be in the message. */
-	ret = trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
-- 
2.1.1

[for-next][PATCH 14/18] tracing/probes: Do not use return value of trace_seq_printf()

[Steven Rostedt]

[-- Attachment #1: 0014-tracing-probes-Do-not-use-return-value-of-trace_seq_.patch --]
[-- Type: text/plain, Size: 1791 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The functions trace_seq_printf() and friends will soon not have a return
value and will only be a void function. Use trace_seq_has_overflowed()
instead to know if the trace_seq operations succeeded or not.

Link: http://lkml.kernel.org/r/20141114011411.530216306@goodmis.org

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_probe.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index d4b9fc22cd27..b983b2fd2ca1 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -40,7 +40,8 @@ const char *reserved_field_names[] = {
 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,	\
 				void *data, void *ent)			\
 {									\
-	return trace_seq_printf(s, " %s=" fmt, name, *(type *)data);	\
+	trace_seq_printf(s, " %s=" fmt, name, *(type *)data);		\
+	return !trace_seq_has_overflowed(s);				\
 }									\
 const char PRINT_TYPE_FMT_NAME(type)[] = fmt;				\
 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
@@ -61,10 +62,11 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
 	int len = *(u32 *)data >> 16;
 
 	if (!len)
-		return trace_seq_printf(s, " %s=(fault)", name);
+		trace_seq_printf(s, " %s=(fault)", name);
 	else
-		return trace_seq_printf(s, " %s=\"%s\"", name,
-					(const char *)get_loc_data(data, ent));
+		trace_seq_printf(s, " %s=\"%s\"", name,
+				 (const char *)get_loc_data(data, ent));
+	return !trace_seq_has_overflowed(s);
 }
 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
 
-- 
2.1.1

[for-next][PATCH 15/18] tracing/uprobes: Do not use return values of trace_seq_printf()

[Steven Rostedt]

[-- Attachment #1: 0015-tracing-uprobes-Do-not-use-return-values-of-trace_se.patch --]
[-- Type: text/plain, Size: 2182 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The functions trace_seq_printf() and friends will soon no longer have
return values. Using trace_seq_has_overflowed() and trace_handle_return()
should be used instead.

Link: http://lkml.kernel.org/r/20141114011411.693008134@goodmis.org
Link: http://lkml.kernel.org/r/20141115050602.333705855@goodmis.org

Reviewed-by: Masami Hiramatsu <masami.hiramatu.pt@hitachi.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_uprobe.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index e35327c787f7..fd76f8e108ef 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -852,16 +852,14 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
 	tu = container_of(event, struct trace_uprobe, tp.call.event);
 
 	if (is_ret_probe(tu)) {
-		if (!trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
-					ftrace_event_name(&tu->tp.call),
-					entry->vaddr[1], entry->vaddr[0]))
-			goto partial;
+		trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
+				 ftrace_event_name(&tu->tp.call),
+				 entry->vaddr[1], entry->vaddr[0]);
 		data = DATAOF_TRACE_ENTRY(entry, true);
 	} else {
-		if (!trace_seq_printf(s, "%s: (0x%lx)",
-					ftrace_event_name(&tu->tp.call),
-					entry->vaddr[0]))
-			goto partial;
+		trace_seq_printf(s, "%s: (0x%lx)",
+				 ftrace_event_name(&tu->tp.call),
+				 entry->vaddr[0]);
 		data = DATAOF_TRACE_ENTRY(entry, false);
 	}
 
@@ -869,14 +867,13 @@ print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *e
 		struct probe_arg *parg = &tu->tp.args[i];
 
 		if (!parg->type->print(s, parg->name, data + parg->offset, entry))
-			goto partial;
+			goto out;
 	}
 
-	if (trace_seq_putc(s, '\n'))
-		return TRACE_TYPE_HANDLED;
+	trace_seq_putc(s, '\n');
 
-partial:
-	return TRACE_TYPE_PARTIAL_LINE;
+ out:
+	return trace_handle_return(s);
 }
 
 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
-- 
2.1.1

[for-next][PATCH 16/18] tracing: Do not use return values of trace_seq_printf() in syscall tracing

[Steven Rostedt]

[-- Attachment #1: 0016-tracing-Do-not-use-return-values-of-trace_seq_printf.patch --]
[-- Type: text/plain, Size: 3127 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The functions trace_seq_printf() and friends will not be returning values
soon and will be void functions. To know if they succeeded or not, the
functions trace_seq_has_overflowed() and trace_handle_return() should be
used instead.

Reviewed-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_syscalls.c | 47 +++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 4dc8b79c5f75..a72f3d8d813e 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -114,7 +114,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
 	struct trace_entry *ent = iter->ent;
 	struct syscall_trace_enter *trace;
 	struct syscall_metadata *entry;
-	int i, ret, syscall;
+	int i, syscall;
 
 	trace = (typeof(trace))ent;
 	syscall = trace->nr;
@@ -128,35 +128,28 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
 		goto end;
 	}
 
-	ret = trace_seq_printf(s, "%s(", entry->name);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_printf(s, "%s(", entry->name);
 
 	for (i = 0; i < entry->nb_args; i++) {
+
+		if (trace_seq_has_overflowed(s))
+			goto end;
+
 		/* parameter types */
-		if (trace_flags & TRACE_ITER_VERBOSE) {
-			ret = trace_seq_printf(s, "%s ", entry->types[i]);
-			if (!ret)
-				return TRACE_TYPE_PARTIAL_LINE;
-		}
+		if (trace_flags & TRACE_ITER_VERBOSE)
+			trace_seq_printf(s, "%s ", entry->types[i]);
+
 		/* parameter values */
-		ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
-				       trace->args[i],
-				       i == entry->nb_args - 1 ? "" : ", ");
-		if (!ret)
-			return TRACE_TYPE_PARTIAL_LINE;
+		trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+				 trace->args[i],
+				 i == entry->nb_args - 1 ? "" : ", ");
 	}
 
-	ret = trace_seq_putc(s, ')');
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
-
+	trace_seq_putc(s, ')');
 end:
-	ret =  trace_seq_putc(s, '\n');
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
+	trace_seq_putc(s, '\n');
 
-	return TRACE_TYPE_HANDLED;
+	return trace_handle_return(s);
 }
 
 static enum print_line_t
@@ -168,7 +161,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 	struct syscall_trace_exit *trace;
 	int syscall;
 	struct syscall_metadata *entry;
-	int ret;
 
 	trace = (typeof(trace))ent;
 	syscall = trace->nr;
@@ -176,7 +168,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 
 	if (!entry) {
 		trace_seq_putc(s, '\n');
-		return TRACE_TYPE_HANDLED;
+		goto out;
 	}
 
 	if (entry->exit_event->event.type != ent->type) {
@@ -184,12 +176,11 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 		return TRACE_TYPE_UNHANDLED;
 	}
 
-	ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+	trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
 				trace->ret);
-	if (!ret)
-		return TRACE_TYPE_PARTIAL_LINE;
 
-	return TRACE_TYPE_HANDLED;
+ out:
+	return trace_handle_return(s);
 }
 
 extern char *__bad_type_size(void);
-- 
2.1.1

[for-next][PATCH 17/18] tracing: Remove return values of most trace_seq_*() functions

[Steven Rostedt]

[-- Attachment #1: 0017-tracing-Remove-return-values-of-most-trace_seq_-func.patch --]
[-- Type: text/plain, Size: 10589 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The trace_seq_printf() and friends are used to store strings into a buffer
that can be passed around from function to function. If the trace_seq buffer
fills up, it will not print any more. The return values were somewhat
inconsistant and using trace_seq_has_overflowed() was a better way to know
if the write to the trace_seq buffer succeeded or not.

Now that all users have removed reading the return value of the printf()
type functions, they can safely return void and keep future users of them
from reading the inconsistent values as well.

Link: http://lkml.kernel.org/r/20141114011411.992510720@goodmis.org

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/trace_seq.h | 37 +++++++++------------
 kernel/trace/trace_seq.c  | 84 +++++++++++++----------------------------------
 2 files changed, 38 insertions(+), 83 deletions(-)

diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 07eda413dfcf..db8a73224f1a 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -57,40 +57,37 @@ static inline bool trace_seq_has_overflowed(struct trace_seq *s)
  */
 #ifdef CONFIG_TRACING
 extern __printf(2, 3)
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
 extern __printf(2, 0)
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
-extern int
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args);
+extern void
 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary);
 extern int trace_print_seq(struct seq_file *m, struct trace_seq *s);
 extern int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 			     int cnt);
-extern int trace_seq_puts(struct trace_seq *s, const char *str);
-extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
-extern int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
-extern int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+extern void trace_seq_puts(struct trace_seq *s, const char *str);
+extern void trace_seq_putc(struct trace_seq *s, unsigned char c);
+extern void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len);
+extern void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 				unsigned int len);
 extern int trace_seq_path(struct trace_seq *s, const struct path *path);
 
-extern int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+extern void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 			     int nmaskbits);
 
 #else /* CONFIG_TRACING */
-static inline int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+static inline void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 {
-	return 0;
 }
-static inline int
+static inline void
 trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
-	return 0;
 }
 
-static inline int
+static inline void
 trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 		  int nmaskbits)
 {
-	return 0;
 }
 
 static inline int trace_print_seq(struct seq_file *m, struct trace_seq *s)
@@ -102,23 +99,19 @@ static inline int trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 {
 	return 0;
 }
-static inline int trace_seq_puts(struct trace_seq *s, const char *str)
+static inline void trace_seq_puts(struct trace_seq *s, const char *str)
 {
-	return 0;
 }
-static inline int trace_seq_putc(struct trace_seq *s, unsigned char c)
+static inline void trace_seq_putc(struct trace_seq *s, unsigned char c)
 {
-	return 0;
 }
-static inline int
+static inline void
 trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
 {
-	return 0;
 }
-static inline int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+static inline void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 				       unsigned int len)
 {
-	return 0;
 }
 static inline int trace_seq_path(struct trace_seq *s, const struct path *path)
 {
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index b100994a17fe..fabfa0f190a3 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -69,20 +69,15 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s)
  * trace_seq_printf() is used to store strings into a special
  * buffer (@s). Then the output may be either used by
  * the sequencer or pulled into another buffer.
- *
- * Returns 1 if we successfully written all the contents to
- *   the buffer.
-  * Returns 0 if we the length to write is bigger than the
- *   reserved buffer space. In this case, nothing gets written.
  */
-int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+void trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	va_list ap;
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	va_start(ap, fmt);
 	ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
@@ -91,12 +86,10 @@ int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 	/* If we can't write it all, don't bother writing anything */
 	if (ret >= len) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->len += ret;
-
-	return 1;
 }
 EXPORT_SYMBOL_GPL(trace_seq_printf);
 
@@ -107,25 +100,18 @@ EXPORT_SYMBOL_GPL(trace_seq_printf);
  * @nmaskbits:	The number of bits that are valid in @maskp
  *
  * Writes a ASCII representation of a bitmask string into @s.
- *
- * Returns 1 if we successfully written all the contents to
- *   the buffer.
- * Returns 0 if we the length to write is bigger than the
- *   reserved buffer space. In this case, nothing gets written.
  */
-int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
+void trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp,
 		      int nmaskbits)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	ret = bitmap_scnprintf(s->buffer + s->len, len, maskp, nmaskbits);
 	s->len += ret;
-
-	return 1;
 }
 EXPORT_SYMBOL_GPL(trace_seq_bitmask);
 
@@ -139,28 +125,24 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask);
  * trace_seq_printf is used to store strings into a special
  * buffer (@s). Then the output may be either used by
  * the sequencer or pulled into another buffer.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+void trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	ret = vsnprintf(s->buffer + s->len, len, fmt, args);
 
 	/* If we can't write it all, don't bother writing anything */
 	if (ret >= len) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->len += ret;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_vprintf);
 
@@ -178,28 +160,24 @@ EXPORT_SYMBOL_GPL(trace_seq_vprintf);
  *
  * This function will take the format and the binary array and finish
  * the conversion into the ASCII string within the buffer.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
+void trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
 	unsigned int len = TRACE_SEQ_BUF_LEFT(s);
 	int ret;
 
 	if (s->full || !len)
-		return 0;
+		return;
 
 	ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
 
 	/* If we can't write it all, don't bother writing anything */
 	if (ret >= len) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->len += ret;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_bprintf);
 
@@ -212,25 +190,21 @@ EXPORT_SYMBOL_GPL(trace_seq_bprintf);
  * copy to user routines. This function records a simple string
  * into a special buffer (@s) for later retrieval by a sequencer
  * or other mechanism.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_puts(struct trace_seq *s, const char *str)
+void trace_seq_puts(struct trace_seq *s, const char *str)
 {
 	unsigned int len = strlen(str);
 
 	if (s->full)
-		return 0;
+		return;
 
 	if (len > TRACE_SEQ_BUF_LEFT(s)) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	memcpy(s->buffer + s->len, str, len);
 	s->len += len;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_puts);
 
@@ -243,22 +217,18 @@ EXPORT_SYMBOL_GPL(trace_seq_puts);
  * copy to user routines. This function records a simple charater
  * into a special buffer (@s) for later retrieval by a sequencer
  * or other mechanism.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_putc(struct trace_seq *s, unsigned char c)
+void trace_seq_putc(struct trace_seq *s, unsigned char c)
 {
 	if (s->full)
-		return 0;
+		return;
 
 	if (TRACE_SEQ_BUF_LEFT(s) < 1) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	s->buffer[s->len++] = c;
-
-	return 1;
 }
 EXPORT_SYMBOL_GPL(trace_seq_putc);
 
@@ -271,23 +241,19 @@ EXPORT_SYMBOL_GPL(trace_seq_putc);
  * There may be cases where raw memory needs to be written into the
  * buffer and a strcpy() would not work. Using this function allows
  * for such cases.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
+void trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len)
 {
 	if (s->full)
-		return 0;
+		return;
 
 	if (len > TRACE_SEQ_BUF_LEFT(s)) {
 		s->full = 1;
-		return 0;
+		return;
 	}
 
 	memcpy(s->buffer + s->len, mem, len);
 	s->len += len;
-
-	return len;
 }
 EXPORT_SYMBOL_GPL(trace_seq_putmem);
 
@@ -303,20 +269,17 @@ EXPORT_SYMBOL_GPL(trace_seq_putmem);
  * This is similar to trace_seq_putmem() except instead of just copying the
  * raw memory into the buffer it writes its ASCII representation of it
  * in hex characters.
- *
- * Returns how much it wrote to the buffer.
  */
-int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
+void trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 			 unsigned int len)
 {
 	unsigned char hex[HEX_CHARS];
 	const unsigned char *data = mem;
 	unsigned int start_len;
 	int i, j;
-	int cnt = 0;
 
 	if (s->full)
-		return 0;
+		return;
 
 	while (len) {
 		start_len = min(len, HEX_CHARS - 1);
@@ -335,9 +298,8 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem,
 		len -= j / 2;
 		hex[j++] = ' ';
 
-		cnt += trace_seq_putmem(s, hex, j);
+		trace_seq_putmem(s, hex, j);
 	}
-	return cnt;
 }
 EXPORT_SYMBOL_GPL(trace_seq_putmem_hex);
 
-- 
2.1.1

[for-next][PATCH 18/18] tracing: Fix return value of ftrace_raw_output_prep()

[Steven Rostedt]

[-- Attachment #1: 0018-tracing-Fix-return-value-of-ftrace_raw_output_prep.patch --]
[-- Type: text/plain, Size: 1670 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

If the trace_seq of ftrace_raw_output_prep() is full this function
returns TRACE_TYPE_PARTIAL_LINE, otherwise it returns zero.

The problem is that TRACE_TYPE_PARTIAL_LINE happens to be zero!

The thing is, the caller of ftrace_raw_output_prep() expects a
success to be zero. Change that to expect it to be
TRACE_TYPE_HANDLED.

Link: http://lkml.kernel.org/r/20141114112522.GA2988@dhcp128.suse.cz

Reminded-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/ftrace.h      | 2 +-
 kernel/trace/trace_output.c | 5 +----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index f13471b5d27a..139b5067345b 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -277,7 +277,7 @@ ftrace_raw_output_##call(struct trace_iterator *iter, int flags,	\
 	field = (typeof(field))iter->ent;				\
 									\
 	ret = ftrace_raw_output_prep(iter, trace_event);		\
-	if (ret)							\
+	if (ret != TRACE_TYPE_HANDLED)					\
 		return ret;						\
 									\
 	trace_seq_printf(s, print);					\
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 163c11b6b8ff..723818bc83b4 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -196,10 +196,7 @@ int ftrace_raw_output_prep(struct trace_iterator *iter,
 	trace_seq_init(p);
 	trace_seq_printf(s, "%s: ", ftrace_event_name(event));
 
-	if (trace_seq_has_overflowed(s))
-		return TRACE_TYPE_PARTIAL_LINE;
-
-	return 0;
+	return trace_handle_return(s);
 }
 EXPORT_SYMBOL(ftrace_raw_output_prep);
 
-- 
2.1.1