[PATCH] preempt_count is int - remove cast and don't assign tounsigned type

From: Jesper Juhl
Date: Wed Apr 27 2005 - 16:22:08 EST


Seeing that you merged my streamline-preempt_count-type-across-archs.patch
(thanks), I believe the small patch below is in order. Please consider it
for inclusion.

In kernel/sched.c the return value from preempt_count() is cast to an int.
That made sense when preempt_count was defined as different types on
different archs, but now that all archs use int for preempt_count the cast
is not needed and should go away. The patch removes the cast.

In kernel/timer.c the return value from preempt_count() is assigned to a
variable of type u32 and then that unsigned value is later compared to
preempt_count(). Since preempt_count() returns an int, an int is what
should be used to store its return value. Storing the result in an
unsigned 32bit integer made a tiny bit of sense back when preempt_count
was different types on different archs, but no more - let's not play
signed vs unsigned comparison games when we don't have to. The patch
modifies the code to use an int to hold the value.
While I was around that bit of code I also made two changes to a nearby
(related) printk() - I modified it to specify the loglevel explicitly and
also broke the line into a few pieces to avoid it being longer than 80
chars and clarified the text a bit.

Signed-off-by: Jesper Juhl <juhl-lkml@xxxxxx>

kernel/sched.c | 2 +-
kernel/timer.c | 8 ++++++--
2 files changed, 7 insertions(+), 3 deletions(-)

--- linux-2.6.12-rc2-mm3-orig/kernel/sched.c.old 2005-04-27 23:05:37.000000000 +0200
+++ linux-2.6.12-rc2-mm3-orig/kernel/sched.c 2005-04-27 23:07:29.000000000 +0200
@@ -2624,7 +2624,7 @@ void fastcall add_preempt_count(int val)
* Underflow?
- BUG_ON(((int)preempt_count() < 0));
+ BUG_ON((preempt_count() < 0));
preempt_count() += val;
* Spinlock count overflowing soon?
--- linux-2.6.12-rc2-mm3-orig/kernel/timer.c 2005-04-11 21:20:56.000000000 +0200
+++ linux-2.6.12-rc2-mm3/kernel/timer.c 2005-04-27 23:04:36.000000000 +0200
@@ -459,10 +459,14 @@ static inline void __run_timers(tvec_bas
detach_timer(timer, 1);
- u32 preempt_count = preempt_count();
+ int preempt_count = preempt_count();
if (preempt_count != preempt_count()) {
- printk("huh, entered %p with %08x, exited with %08x?\n", fn, preempt_count, preempt_count());
+ printk(KERN_WARNING "huh, entered %p "
+ "with preempt_count %08x, exited"
+ " with %08x?\n",
+ fn, preempt_count,
+ preempt_count());

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