From: Thomas Gleixner <tglx@linutronix.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>,
SCSI <linux-scsi@vger.kernel.org>,
James Bottomley <James.Bottomley@SteelEye.com>
Subject: [PATCH] SCSI: Replace semaphores with wait_even
Date: Wed, 20 Oct 2004 21:29:39 +0200 [thread overview]
Message-ID: <1098300579.20821.65.camel@thomas> (raw)
Use wait_event instead of semaphores. Semaphores are slower
and trigger owner conflicts during semaphore debugging.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
---
2.6.9-bk-041020-thomas/drivers/scsi/hosts.c | 2 +-
2.6.9-bk-041020-thomas/drivers/scsi/scsi_error.c | 19
++++++++-----------
2.6.9-bk-041020-thomas/include/scsi/scsi_host.h | 2 +-
3 files changed, 10 insertions(+), 13 deletions(-)
diff -puN drivers/scsi/scsi_error.c~scsihost drivers/scsi/scsi_error.c
--- 2.6.9-bk-041020/drivers/scsi/scsi_error.c~scsihost 2004-10-20
15:58:57.000000000 +0200
+++ 2.6.9-bk-041020-thomas/drivers/scsi/scsi_error.c 2004-10-20
16:02:57.000000000 +0200
@@ -49,7 +49,7 @@
void scsi_eh_wakeup(struct Scsi_Host *shost)
{
if (shost->host_busy == shost->host_failed) {
- up(shost->eh_wait);
+ wake_up(shost->eh_wait);
SCSI_LOG_ERROR_RECOVERY(5,
printk("Waking error handler thread\n"));
}
@@ -1598,7 +1598,7 @@ int scsi_error_handler(void *data)
{
struct Scsi_Host *shost = (struct Scsi_Host *) data;
int rtn;
- DECLARE_MUTEX_LOCKED(sem);
+ DECLARE_WAIT_QUEUE_HEAD(eh_wait);
/*
* Flush resources
@@ -1608,7 +1608,7 @@ int scsi_error_handler(void *data)
current->flags |= PF_NOFREEZE;
- shost->eh_wait = &sem;
+ shost->eh_wait = &eh_wait;
shost->ehandler = current;
/*
@@ -1630,15 +1630,12 @@ int scsi_error_handler(void *data)
" sleeping\n",shost->host_no));
/*
- * Note - we always use down_interruptible with the semaphore
- * even if the module was loaded as part of the kernel. The
- * reason is that down() will cause this thread to be counted
- * in the load average as a running process, and down
- * interruptible doesn't. Given that we need to allow this
- * thread to die if the driver was loaded as a module, using
- * semaphores isn't unreasonable.
+ * Wait, until somebody decides to wake us due to an error
+ * or because we should be killed
*/
- down_interruptible(&sem);
+ wait_event_interruptible(eh_wait, shost->eh_kill ||
+ (shost->host_busy == shost->host_failed));
+
if (shost->eh_kill)
break;
diff -puN drivers/scsi/hosts.c~scsihost drivers/scsi/hosts.c
--- 2.6.9-bk-041020/drivers/scsi/hosts.c~scsihost 2004-10-20
16:00:04.000000000 +0200
+++ 2.6.9-bk-041020-thomas/drivers/scsi/hosts.c 2004-10-20
16:00:35.000000000 +0200
@@ -157,7 +157,7 @@ static void scsi_host_dev_release(struct
DECLARE_COMPLETION(sem);
shost->eh_notify = &sem;
shost->eh_kill = 1;
- up(shost->eh_wait);
+ wake_up(shost->eh_wait);
wait_for_completion(&sem);
shost->eh_notify = NULL;
}
diff -puN include/scsi/scsi_host.h~scsihost include/scsi/scsi_host.h
--- 2.6.9-bk-041020/include/scsi/scsi_host.h~scsihost 2004-10-20
16:00:12.000000000 +0200
+++ 2.6.9-bk-041020-thomas/include/scsi/scsi_host.h 2004-10-20
16:00:29.000000000 +0200
@@ -396,7 +396,7 @@ struct Scsi_Host {
struct list_head eh_cmd_q;
struct task_struct * ehandler; /* Error recovery thread. */
- struct semaphore * eh_wait; /* The error recovery thread waits
+ wait_queue_head_t * eh_wait; /* The error recovery thread waits
on this. */
struct completion * eh_notify; /* wait for eh to begin or end */
struct semaphore * eh_action; /* Wait for specific actions on the
_
next reply other threads:[~2004-10-20 19:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-20 19:29 Thomas Gleixner [this message]
2004-10-24 19:57 ` [PATCH] SCSI: Replace semaphores with wait_even James Bottomley
2004-10-24 20:06 ` Thomas Gleixner
2004-10-24 23:01 ` James Bottomley
2004-10-24 23:06 ` Ingo Molnar
2004-10-25 0:02 ` James Bottomley
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