From: Mikael Pettersson <mikpe@user.it.uu.se>
This patch fixes an illegal sleep issue in perfctr's virtualised
per-process counters: a spinlock is taken around calls to
perfctr_cpu_{reserve,release}() which sleeps on a mutex. Change the
spinlock to a mutex too.
The problem was reported by Sami Farin.
Strangely enough, DEBUG_SPINLOCK_SLEEP only triggers if I also have PREEMPT
enabled. Is it supposed to be like that?
Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/perfctr/virtual.c | 10 +++++-----
1 files changed, 5 insertions(+), 5 deletions(-)
diff -puN drivers/perfctr/virtual.c~virtual-perfctr-illegal-sleep drivers/perfctr/virtual.c
--- 25/drivers/perfctr/virtual.c~virtual-perfctr-illegal-sleep Wed Sep 22 16:37:37 2004
+++ 25-akpm/drivers/perfctr/virtual.c Wed Sep 22 16:37:37 2004
@@ -111,7 +111,7 @@ static inline void vperfctr_task_unlock(
****************************************************************/
/* XXX: perhaps relax this to number of _live_ perfctrs */
-static spinlock_t nrctrs_lock = SPIN_LOCK_UNLOCKED;
+static DECLARE_MUTEX(nrctrs_mutex);
static int nrctrs;
static const char this_service[] = __FILE__;
@@ -120,13 +120,13 @@ static int inc_nrctrs(void)
const char *other;
other = NULL;
- spin_lock(&nrctrs_lock);
+ down(&nrctrs_mutex);
if (++nrctrs == 1) {
other = perfctr_cpu_reserve(this_service);
if (other)
nrctrs = 0;
}
- spin_unlock(&nrctrs_lock);
+ up(&nrctrs_mutex);
if (other) {
printk(KERN_ERR __FILE__
": cannot operate, perfctr hardware taken by '%s'\n",
@@ -139,10 +139,10 @@ static int inc_nrctrs(void)
static void dec_nrctrs(void)
{
- spin_lock(&nrctrs_lock);
+ down(&nrctrs_mutex);
if (--nrctrs == 0)
perfctr_cpu_release(this_service);
- spin_unlock(&nrctrs_lock);
+ up(&nrctrs_mutex);
}
/* Allocate a `struct vperfctr'. Claim and reserve
_