[PATCH] stacktrace: get rid of unneeded !!

[PATCH] stacktrace: get rid of unneeded !!

[Jiri Slaby]

My commit b0c51f158455 ("stacktrace: Don't skip first entry on
noncurrent tasks") adds one or zero to skipnr by "!!(current == tsk)".
But the C99 standard says:
  The == (equal to) and != (not equal to) operators are
  ...
  Each of the operators yields 1 if the specified relation is true and 0
  if it is false.

So there is no need to prepend the above expression by "!!" -- remove
it.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
---
 kernel/stacktrace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index c9ea7eb2cb1a..2af66e449aa6 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -142,7 +142,7 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
 		.store	= store,
 		.size	= size,
 		/* skip this function if they are tracing us */
-		.skip	= skipnr + !!(current == tsk),
+		.skip	= skipnr + (current == tsk),
 	};
 
 	if (!try_get_task_stack(tsk))
@@ -300,7 +300,7 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
 		.entries	= store,
 		.max_entries	= size,
 		/* skip this function if they are tracing us */
-		.skip	= skipnr + !!(current == task),
+		.skip	= skipnr + (current == task),
 	};
 
 	save_stack_trace_tsk(task, &trace);
-- 
2.24.0

[tip: core/stacktrace] stacktrace: Get rid of unneeded '!!' pattern

[tip-bot2 for Jiri Slaby]

The following commit has been merged into the core/stacktrace branch of tip:

Commit-ID:     4b48512c2e9c63b62d7da23563cdb224b4d61d72
Gitweb:        https://git.kernel.org/tip/4b48512c2e9c63b62d7da23563cdb224b4d61d72
Author:        Jiri Slaby <jslaby@suse.cz>
AuthorDate:    Mon, 11 Nov 2019 10:26:47 +01:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Mon, 11 Nov 2019 10:30:59 +01:00

stacktrace: Get rid of unneeded '!!' pattern

My commit b0c51f158455 ("stacktrace: Don't skip first entry on
noncurrent tasks") adds one or zero to skipnr by "!!(current == tsk)".

But the C99 standard says:

  The == (equal to) and != (not equal to) operators are
  ...
  Each of the operators yields 1 if the specified relation is true and 0
  if it is false.

So there is no need to prepend the above expression by "!!" -- remove it.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191111092647.27419-1-jslaby@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/stacktrace.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index c9ea7eb..2af66e4 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -142,7 +142,7 @@ unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
 		.store	= store,
 		.size	= size,
 		/* skip this function if they are tracing us */
-		.skip	= skipnr + !!(current == tsk),
+		.skip	= skipnr + (current == tsk),
 	};
 
 	if (!try_get_task_stack(tsk))
@@ -300,7 +300,7 @@ unsigned int stack_trace_save_tsk(struct task_struct *task,
 		.entries	= store,
 		.max_entries	= size,
 		/* skip this function if they are tracing us */
-		.skip	= skipnr + !!(current == task),
+		.skip	= skipnr + (current == task),
 	};
 
 	save_stack_trace_tsk(task, &trace);