[PATCH V2 23/23] printk: Move kmsg_dump functions to separate file

[Joe Perches <joe@perches.com>]

Generic restructuring.

Create kmsg_dump.c, add to Makefile and remove from printk.c

Signed-off-by: Joe Perches <joe@perches.com>
---
 kernel/printk/Makefile    |    1 +
 kernel/printk/kmsg_dump.c |  328 +++++++++++++++++++++++++++++++++++++++++++++
 kernel/printk/printk.c    |  318 -------------------------------------------
 3 files changed, 329 insertions(+), 318 deletions(-)
 create mode 100644 kernel/printk/kmsg_dump.c

diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 7947661..b0072b0 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -2,4 +2,5 @@ obj-y	= printk.o
 obj-y	+= printk_log.o
 obj-y	+= devkmsg.o
 obj-y	+= printk_syslog.o
+obj-y	+= kmsg_dump.o
 obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)	+= braille.o
diff --git a/kernel/printk/kmsg_dump.c b/kernel/printk/kmsg_dump.c
new file mode 100644
index 0000000..7962172
--- /dev/null
+++ b/kernel/printk/kmsg_dump.c
@@ -0,0 +1,328 @@
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/kexec.h>
+#include <linux/moduleparam.h>
+#include <linux/export.h>
+#include <linux/kmsg_dump.h>
+#include <linux/rculist.h>
+#include <linux/stat.h>
+
+#include "printk_log.h"
+
+static DEFINE_SPINLOCK(dump_list_lock);
+static LIST_HEAD(dump_list);
+
+/**
+ * kmsg_dump_register - register a kernel log dumper.
+ * @dumper: pointer to the kmsg_dumper structure
+ *
+ * Adds a kernel log dumper to the system. The dump callback in the
+ * structure will be called when the kernel oopses or panics and must be
+ * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
+ */
+int kmsg_dump_register(struct kmsg_dumper *dumper)
+{
+	unsigned long flags;
+	int err = -EBUSY;
+
+	/* The dump callback needs to be set */
+	if (!dumper->dump)
+		return -EINVAL;
+
+	spin_lock_irqsave(&dump_list_lock, flags);
+	/* Don't allow registering multiple times */
+	if (!dumper->registered) {
+		dumper->registered = 1;
+		list_add_tail_rcu(&dumper->list, &dump_list);
+		err = 0;
+	}
+	spin_unlock_irqrestore(&dump_list_lock, flags);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_register);
+
+/**
+ * kmsg_dump_unregister - unregister a kmsg dumper.
+ * @dumper: pointer to the kmsg_dumper structure
+ *
+ * Removes a dump device from the system. Returns zero on success and
+ * %-EINVAL otherwise.
+ */
+int kmsg_dump_unregister(struct kmsg_dumper *dumper)
+{
+	unsigned long flags;
+	int err = -EINVAL;
+
+	spin_lock_irqsave(&dump_list_lock, flags);
+	if (dumper->registered) {
+		dumper->registered = 0;
+		list_del_rcu(&dumper->list);
+		err = 0;
+	}
+	spin_unlock_irqrestore(&dump_list_lock, flags);
+	synchronize_rcu();
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+
+static bool always_kmsg_dump;
+module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
+
+/**
+ * kmsg_dump - dump kernel log to kernel message dumpers.
+ * @reason: the reason (oops, panic etc) for dumping
+ *
+ * Call each of the registered dumper's dump() callback, which can
+ * retrieve the kmsg records with kmsg_dump_get_line() or
+ * kmsg_dump_get_buffer().
+ */
+void kmsg_dump(enum kmsg_dump_reason reason)
+{
+	struct kmsg_dumper *dumper;
+	unsigned long flags;
+
+	if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(dumper, &dump_list, list) {
+		if (dumper->max_reason && reason > dumper->max_reason)
+			continue;
+
+		/* initialize iterator with data about the stored records */
+		dumper->active = true;
+
+		raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+		dumper->cur_seq = printk_log_clear_seq;
+		dumper->cur_idx = printk_log_clear_idx;
+		dumper->next_seq = printk_log_next_seq;
+		dumper->next_idx = printk_log_next_idx;
+		raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+
+		/* invoke dumper which will iterate over records */
+		dumper->dump(dumper, reason);
+
+		/* reset iterator */
+		dumper->active = false;
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @line: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the beginning of the kmsg buffer, with the oldest kmsg
+ * record, and copy one record into the provided buffer.
+ *
+ * Consecutive calls will return the next available record moving
+ * towards the end of the buffer with the youngest messages.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ *
+ * The function is similar to kmsg_dump_get_line(), but grabs no locks.
+ */
+bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
+			       char *line, size_t size, size_t *len)
+{
+	struct printk_log *msg;
+	size_t l = 0;
+	bool ret = false;
+
+	if (!dumper->active)
+		goto out;
+
+	if (dumper->cur_seq < printk_log_first_seq) {
+		/* messages are gone, move to first available one */
+		dumper->cur_seq = printk_log_first_seq;
+		dumper->cur_idx = printk_log_first_idx;
+	}
+
+	/* last entry */
+	if (dumper->cur_seq >= printk_log_next_seq)
+		goto out;
+
+	msg = printk_log_from_idx(dumper->cur_idx);
+	l = printk_msg_print_text(msg, 0, syslog, line, size);
+
+	dumper->cur_idx = printk_log_next(dumper->cur_idx);
+	dumper->cur_seq++;
+	ret = true;
+out:
+	if (len)
+		*len = l;
+	return ret;
+}
+
+/**
+ * kmsg_dump_get_line - retrieve one kmsg log line
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @line: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the beginning of the kmsg buffer, with the oldest kmsg
+ * record, and copy one record into the provided buffer.
+ *
+ * Consecutive calls will return the next available record moving
+ * towards the end of the buffer with the youngest messages.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
+			char *line, size_t size, size_t *len)
+{
+	unsigned long flags;
+	bool ret;
+
+	raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
+	raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+
+/**
+ * kmsg_dump_get_buffer - copy kmsg log lines
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @buf: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the end of the kmsg buffer and fill the provided buffer
+ * with as many of the the *youngest* kmsg records that fit into it.
+ * If the buffer is large enough, all available kmsg records will be
+ * copied with a single call.
+ *
+ * Consecutive calls will fill the buffer with the next block of
+ * available older records, not including the earlier retrieved ones.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+			  char *buf, size_t size, size_t *len)
+{
+	unsigned long flags;
+	u64 seq;
+	u32 idx;
+	u64 next_seq;
+	u32 next_idx;
+	enum printk_log_flags prev;
+	size_t l = 0;
+	bool ret = false;
+
+	if (!dumper->active)
+		goto out;
+
+	raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+	if (dumper->cur_seq < printk_log_first_seq) {
+		/* messages are gone, move to first available one */
+		dumper->cur_seq = printk_log_first_seq;
+		dumper->cur_idx = printk_log_first_idx;
+	}
+
+	/* last entry */
+	if (dumper->cur_seq >= dumper->next_seq) {
+		raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+		goto out;
+	}
+
+	/* calculate length of entire buffer */
+	seq = dumper->cur_seq;
+	idx = dumper->cur_idx;
+	prev = 0;
+	while (seq < dumper->next_seq) {
+		struct printk_log *msg = printk_log_from_idx(idx);
+
+		l += printk_msg_print_text(msg, prev, true, NULL, 0);
+		idx = printk_log_next(idx);
+		seq++;
+		prev = msg->flags;
+	}
+
+	/* move first record forward until length fits into the buffer */
+	seq = dumper->cur_seq;
+	idx = dumper->cur_idx;
+	prev = 0;
+	while (l > size && seq < dumper->next_seq) {
+		struct printk_log *msg = printk_log_from_idx(idx);
+
+		l -= printk_msg_print_text(msg, prev, true, NULL, 0);
+		idx = printk_log_next(idx);
+		seq++;
+		prev = msg->flags;
+	}
+
+	/* last message in next interation */
+	next_seq = seq;
+	next_idx = idx;
+
+	l = 0;
+	prev = 0;
+	while (seq < dumper->next_seq) {
+		struct printk_log *msg = printk_log_from_idx(idx);
+
+		l += printk_msg_print_text(msg, prev, syslog, buf + l, size - l);
+		idx = printk_log_next(idx);
+		seq++;
+		prev = msg->flags;
+	}
+
+	dumper->next_seq = next_seq;
+	dumper->next_idx = next_idx;
+	ret = true;
+	raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+out:
+	if (len)
+		*len = l;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+
+/**
+ * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
+ * @dumper: registered kmsg dumper
+ *
+ * Reset the dumper's iterator so that kmsg_dump_get_line() and
+ * kmsg_dump_get_buffer() can be called again and used multiple
+ * times within the same dumper.dump() callback.
+ *
+ * The function is similar to kmsg_dump_rewind(), but grabs no locks.
+ */
+void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
+{
+	dumper->cur_seq = printk_log_clear_seq;
+	dumper->cur_idx = printk_log_clear_idx;
+	dumper->next_seq = printk_log_next_seq;
+	dumper->next_idx = printk_log_next_idx;
+}
+
+/**
+ * kmsg_dump_rewind - reset the interator
+ * @dumper: registered kmsg dumper
+ *
+ * Reset the dumper's iterator so that kmsg_dump_get_line() and
+ * kmsg_dump_get_buffer() can be called again and used multiple
+ * times within the same dumper.dump() callback.
+ */
+void kmsg_dump_rewind(struct kmsg_dumper *dumper)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
+	kmsg_dump_rewind_nolock(dumper);
+	raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index bed0e7d..9b31ded 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -33,7 +33,6 @@
 #include <linux/kexec.h>
 #include <linux/kdb.h>
 #include <linux/ratelimit.h>
-#include <linux/kmsg_dump.h>
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/rculist.h>
@@ -1511,321 +1510,4 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 }
 EXPORT_SYMBOL(printk_timed_ratelimit);
 
-static DEFINE_SPINLOCK(dump_list_lock);
-static LIST_HEAD(dump_list);
-
-/**
- * kmsg_dump_register - register a kernel log dumper.
- * @dumper: pointer to the kmsg_dumper structure
- *
- * Adds a kernel log dumper to the system. The dump callback in the
- * structure will be called when the kernel oopses or panics and must be
- * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
- */
-int kmsg_dump_register(struct kmsg_dumper *dumper)
-{
-	unsigned long flags;
-	int err = -EBUSY;
-
-	/* The dump callback needs to be set */
-	if (!dumper->dump)
-		return -EINVAL;
-
-	spin_lock_irqsave(&dump_list_lock, flags);
-	/* Don't allow registering multiple times */
-	if (!dumper->registered) {
-		dumper->registered = 1;
-		list_add_tail_rcu(&dumper->list, &dump_list);
-		err = 0;
-	}
-	spin_unlock_irqrestore(&dump_list_lock, flags);
-
-	return err;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_register);
-
-/**
- * kmsg_dump_unregister - unregister a kmsg dumper.
- * @dumper: pointer to the kmsg_dumper structure
- *
- * Removes a dump device from the system. Returns zero on success and
- * %-EINVAL otherwise.
- */
-int kmsg_dump_unregister(struct kmsg_dumper *dumper)
-{
-	unsigned long flags;
-	int err = -EINVAL;
-
-	spin_lock_irqsave(&dump_list_lock, flags);
-	if (dumper->registered) {
-		dumper->registered = 0;
-		list_del_rcu(&dumper->list);
-		err = 0;
-	}
-	spin_unlock_irqrestore(&dump_list_lock, flags);
-	synchronize_rcu();
-
-	return err;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
-
-static bool always_kmsg_dump;
-module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
-
-/**
- * kmsg_dump - dump kernel log to kernel message dumpers.
- * @reason: the reason (oops, panic etc) for dumping
- *
- * Call each of the registered dumper's dump() callback, which can
- * retrieve the kmsg records with kmsg_dump_get_line() or
- * kmsg_dump_get_buffer().
- */
-void kmsg_dump(enum kmsg_dump_reason reason)
-{
-	struct kmsg_dumper *dumper;
-	unsigned long flags;
-
-	if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
-		return;
-
-	rcu_read_lock();
-	list_for_each_entry_rcu(dumper, &dump_list, list) {
-		if (dumper->max_reason && reason > dumper->max_reason)
-			continue;
-
-		/* initialize iterator with data about the stored records */
-		dumper->active = true;
-
-		raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
-		dumper->cur_seq = printk_log_clear_seq;
-		dumper->cur_idx = printk_log_clear_idx;
-		dumper->next_seq = printk_log_next_seq;
-		dumper->next_idx = printk_log_next_idx;
-		raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-
-		/* invoke dumper which will iterate over records */
-		dumper->dump(dumper, reason);
-
-		/* reset iterator */
-		dumper->active = false;
-	}
-	rcu_read_unlock();
-}
-
-/**
- * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
- * @dumper: registered kmsg dumper
- * @syslog: include the "<4>" prefixes
- * @line: buffer to copy the line to
- * @size: maximum size of the buffer
- * @len: length of line placed into buffer
- *
- * Start at the beginning of the kmsg buffer, with the oldest kmsg
- * record, and copy one record into the provided buffer.
- *
- * Consecutive calls will return the next available record moving
- * towards the end of the buffer with the youngest messages.
- *
- * A return value of FALSE indicates that there are no more records to
- * read.
- *
- * The function is similar to kmsg_dump_get_line(), but grabs no locks.
- */
-bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
-			       char *line, size_t size, size_t *len)
-{
-	struct printk_log *msg;
-	size_t l = 0;
-	bool ret = false;
-
-	if (!dumper->active)
-		goto out;
-
-	if (dumper->cur_seq < printk_log_first_seq) {
-		/* messages are gone, move to first available one */
-		dumper->cur_seq = printk_log_first_seq;
-		dumper->cur_idx = printk_log_first_idx;
-	}
-
-	/* last entry */
-	if (dumper->cur_seq >= printk_log_next_seq)
-		goto out;
-
-	msg = printk_log_from_idx(dumper->cur_idx);
-	l = printk_msg_print_text(msg, 0, syslog, line, size);
-
-	dumper->cur_idx = printk_log_next(dumper->cur_idx);
-	dumper->cur_seq++;
-	ret = true;
-out:
-	if (len)
-		*len = l;
-	return ret;
-}
-
-/**
- * kmsg_dump_get_line - retrieve one kmsg log line
- * @dumper: registered kmsg dumper
- * @syslog: include the "<4>" prefixes
- * @line: buffer to copy the line to
- * @size: maximum size of the buffer
- * @len: length of line placed into buffer
- *
- * Start at the beginning of the kmsg buffer, with the oldest kmsg
- * record, and copy one record into the provided buffer.
- *
- * Consecutive calls will return the next available record moving
- * towards the end of the buffer with the youngest messages.
- *
- * A return value of FALSE indicates that there are no more records to
- * read.
- */
-bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
-			char *line, size_t size, size_t *len)
-{
-	unsigned long flags;
-	bool ret;
-
-	raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
-	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
-	raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
-
-/**
- * kmsg_dump_get_buffer - copy kmsg log lines
- * @dumper: registered kmsg dumper
- * @syslog: include the "<4>" prefixes
- * @buf: buffer to copy the line to
- * @size: maximum size of the buffer
- * @len: length of line placed into buffer
- *
- * Start at the end of the kmsg buffer and fill the provided buffer
- * with as many of the the *youngest* kmsg records that fit into it.
- * If the buffer is large enough, all available kmsg records will be
- * copied with a single call.
- *
- * Consecutive calls will fill the buffer with the next block of
- * available older records, not including the earlier retrieved ones.
- *
- * A return value of FALSE indicates that there are no more records to
- * read.
- */
-bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
-			  char *buf, size_t size, size_t *len)
-{
-	unsigned long flags;
-	u64 seq;
-	u32 idx;
-	u64 next_seq;
-	u32 next_idx;
-	enum printk_log_flags prev;
-	size_t l = 0;
-	bool ret = false;
-
-	if (!dumper->active)
-		goto out;
-
-	raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
-	if (dumper->cur_seq < printk_log_first_seq) {
-		/* messages are gone, move to first available one */
-		dumper->cur_seq = printk_log_first_seq;
-		dumper->cur_idx = printk_log_first_idx;
-	}
-
-	/* last entry */
-	if (dumper->cur_seq >= dumper->next_seq) {
-		raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-		goto out;
-	}
-
-	/* calculate length of entire buffer */
-	seq = dumper->cur_seq;
-	idx = dumper->cur_idx;
-	prev = 0;
-	while (seq < dumper->next_seq) {
-		struct printk_log *msg = printk_log_from_idx(idx);
-
-		l += printk_msg_print_text(msg, prev, true, NULL, 0);
-		idx = printk_log_next(idx);
-		seq++;
-		prev = msg->flags;
-	}
-
-	/* move first record forward until length fits into the buffer */
-	seq = dumper->cur_seq;
-	idx = dumper->cur_idx;
-	prev = 0;
-	while (l > size && seq < dumper->next_seq) {
-		struct printk_log *msg = printk_log_from_idx(idx);
-
-		l -= printk_msg_print_text(msg, prev, true, NULL, 0);
-		idx = printk_log_next(idx);
-		seq++;
-		prev = msg->flags;
-	}
-
-	/* last message in next interation */
-	next_seq = seq;
-	next_idx = idx;
-
-	l = 0;
-	prev = 0;
-	while (seq < dumper->next_seq) {
-		struct printk_log *msg = printk_log_from_idx(idx);
-
-		l += printk_msg_print_text(msg, prev, syslog, buf + l, size - l);
-		idx = printk_log_next(idx);
-		seq++;
-		prev = msg->flags;
-	}
-
-	dumper->next_seq = next_seq;
-	dumper->next_idx = next_idx;
-	ret = true;
-	raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-out:
-	if (len)
-		*len = l;
-	return ret;
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
-
-/**
- * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
- * @dumper: registered kmsg dumper
- *
- * Reset the dumper's iterator so that kmsg_dump_get_line() and
- * kmsg_dump_get_buffer() can be called again and used multiple
- * times within the same dumper.dump() callback.
- *
- * The function is similar to kmsg_dump_rewind(), but grabs no locks.
- */
-void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
-{
-	dumper->cur_seq = printk_log_clear_seq;
-	dumper->cur_idx = printk_log_clear_idx;
-	dumper->next_seq = printk_log_next_seq;
-	dumper->next_idx = printk_log_next_idx;
-}
-
-/**
- * kmsg_dump_rewind - reset the interator
- * @dumper: registered kmsg dumper
- *
- * Reset the dumper's iterator so that kmsg_dump_get_line() and
- * kmsg_dump_get_buffer() can be called again and used multiple
- * times within the same dumper.dump() callback.
- */
-void kmsg_dump_rewind(struct kmsg_dumper *dumper)
-{
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&printk_logbuf_lock, flags);
-	kmsg_dump_rewind_nolock(dumper);
-	raw_spin_unlock_irqrestore(&printk_logbuf_lock, flags);
-}
-EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
 #endif
-- 
1.7.8.112.g3fd21