scsi: convert host_busy to atomic_t
Avoid taking the host-wide host_lock to check the per-host queue limit.
Instead we do an atomic_inc_return early on to grab our slot in the queue,
and if necessary decrement it after finishing all checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Webb Scales <webbnh@hp.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Robert Elliott <elliott@hp.com>
diff --git a/drivers/scsi/advansys.c b/drivers/scsi/advansys.c
index e716d0a..43761c1 100644
--- a/drivers/scsi/advansys.c
+++ b/drivers/scsi/advansys.c
@@ -2512,7 +2512,7 @@
printk("Scsi_Host at addr 0x%p, device %s\n", s, dev_name(boardp->dev));
printk(" host_busy %u, host_no %d,\n",
- s->host_busy, s->host_no);
+ atomic_read(&s->host_busy), s->host_no);
printk(" base 0x%lx, io_port 0x%lx, irq %d,\n",
(ulong)s->base, (ulong)s->io_port, boardp->irq);
@@ -3346,7 +3346,7 @@
seq_printf(m,
" host_busy %u, max_id %u, max_lun %llu, max_channel %u\n",
- shost->host_busy, shost->max_id,
+ atomic_read(&shost->host_busy), shost->max_id,
shost->max_lun, shost->max_channel);
seq_printf(m,