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authorJeff Garzik <jeff@garzik.org>2010-11-16 02:10:29 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-16 13:33:23 -0800
commitf281233d3eba15fb225d21ae2e228fd4553d824a (patch)
tree51134454ba8acb558735f90be5540f7d756483e3 /drivers/ata
parentbdbd01ac444bffb3c9aefed3059d12554059b320 (diff)
downloadop-kernel-dev-f281233d3eba15fb225d21ae2e228fd4553d824a.zip
op-kernel-dev-f281233d3eba15fb225d21ae2e228fd4553d824a.tar.gz
SCSI host lock push-down
Move the mid-layer's ->queuecommand() invocation from being locked with the host lock to being unlocked to facilitate speeding up the critical path for drivers who don't need this lock taken anyway. The patch below presents a simple SCSI host lock push-down as an equivalent transformation. No locking or other behavior should change with this patch. All existing bugs and locking orders are preserved. Additionally, add one parameter to queuecommand, struct Scsi_Host * and remove one parameter from queuecommand, void (*done)(struct scsi_cmnd *) Scsi_Host* is a convenient pointer that most host drivers need anyway, and 'done' is redundant to struct scsi_cmnd->scsi_done. Minimal code disturbance was attempted with this change. Most drivers needed only two one-line modifications for their host lock push-down. Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Acked-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/ata')
-rw-r--r--drivers/ata/libata-scsi.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 3f91c01..19835d3 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3183,7 +3183,7 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
* Return value from __ata_scsi_queuecmd() if @cmd can be queued,
* 0 otherwise.
*/
-int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
+static int ata_scsi_queuecmd_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
{
struct ata_port *ap;
struct ata_device *dev;
@@ -3211,6 +3211,8 @@ int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
return rc;
}
+DEF_SCSI_QCMD(ata_scsi_queuecmd)
+
/**
* ata_scsi_simulate - simulate SCSI command on ATA device
* @dev: the target device
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