Messages in this thread | | | From | "Elliott, Robert (Server Storage)" <> | Subject | RE: [PATCH 10/14] scsi: only maintain target_blocked if the driver has a target queue limit | Date | Sat, 21 Jun 2014 22:10:14 +0000 |
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> -----Original Message----- > From: Christoph Hellwig [mailto:hch@lst.de] > Sent: Thursday, 12 June, 2014 8:49 AM > To: James Bottomley > Cc: Jens Axboe; Bart Van Assche; Elliott, Robert (Server Storage); linux- > scsi@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: [PATCH 10/14] scsi: only maintain target_blocked if the driver has a > target queue limit > > This saves us an atomic operation for each I/O submission and completion > for the usual case where the driver doesn't set a per-target can_queue > value. Only a few iscsi hardware offload drivers set the per-target > can_queue value at the moment. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > drivers/scsi/scsi_lib.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 0e33dee..763b3c9 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c ...
> @@ -1642,7 +1648,8 @@ static void scsi_request_fn(struct request_queue *q) > return; > > host_not_ready: > - atomic_dec(&scsi_target(sdev)->target_busy); > + if (&scsi_target(sdev)->can_queue > 0) > + atomic_dec(&scsi_target(sdev)->target_busy); > not_ready: > /* > * lock q, handle tag, requeue req, and decrement device_busy. We
There's an extra & in that if statement.
--- Rob Elliott HP Server Storage
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