diff options
| author | Ben Collins <bcollins@ubuntu.com> | 2012-06-11 14:44:44 -0400 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-07-20 08:58:44 +0100 |
| commit | 30002f1c02ada69342443e7ed5ee9118feb89510 (patch) | |
| tree | 369369427cbbfd3b1bdeabd7aa7ed8355f1e53e9 | |
| parent | 361ee9c3f3839d6cbd306b5bd34292e0848ecfdc (diff) | |
[SCSI] aacraid: Relax the tight timeout loop on fib commands
The loop that waited for syncronous fib commands was causing a CPU stall
when a timeout actually occured.
1) Switch to using a more accurate timeout mechanism.
2) Do not pace the loop with udelay(). Use cpu_relax() to allow for
scheduling to occur.
Signed-off-by: Ben Collins <bcollins@ubuntu.com>
Acked-by: Achim Leubner <Achim_Leubner@pmc-sierra.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
| -rw-r--r-- | drivers/scsi/aacraid/commsup.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/scsi/aacraid/commsup.c b/drivers/scsi/aacraid/commsup.c index 4b32ca442433..906a5013edae 100644 --- a/drivers/scsi/aacraid/commsup.c +++ b/drivers/scsi/aacraid/commsup.c @@ -564,10 +564,10 @@ int aac_fib_send(u16 command, struct fib *fibptr, unsigned long size, * functioning because an interrupt routing or other * hardware failure has occurred. */ - unsigned long count = 36000000L; /* 3 minutes */ + unsigned long timeout = jiffies + (180 * HZ); /* 3 minutes */ while (down_trylock(&fibptr->event_wait)) { int blink; - if (--count == 0) { + if (time_is_before_eq_jiffies(timeout)) { struct aac_queue * q = &dev->queues->queue[AdapNormCmdQueue]; spin_lock_irqsave(q->lock, qflags); q->numpending--; @@ -588,7 +588,10 @@ int aac_fib_send(u16 command, struct fib *fibptr, unsigned long size, } return -EFAULT; } - udelay(5); + /* We used to udelay() here but that absorbed + * a CPU when a timeout occured. Not very + * useful. */ + cpu_relax(); } } else if (down_interruptible(&fibptr->event_wait)) { /* Do nothing ... satisfy |