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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 16:33:23 -0500
commitf281233d3eba15fb225d21ae2e228fd4553d824a (patch)
tree51134454ba8acb558735f90be5540f7d756483e3 /include/linux/libata.h
parentbdbd01ac444bffb3c9aefed3059d12554059b320 (diff)
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 'include/linux/libata.h')
-rw-r--r--include/linux/libata.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 15b77b8dc7e1..d947b1231662 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -986,7 +986,7 @@ extern void ata_host_init(struct ata_host *, struct device *,
986 unsigned long, struct ata_port_operations *); 986 unsigned long, struct ata_port_operations *);
987extern int ata_scsi_detect(struct scsi_host_template *sht); 987extern int ata_scsi_detect(struct scsi_host_template *sht);
988extern int ata_scsi_ioctl(struct scsi_device *dev, int cmd, void __user *arg); 988extern int ata_scsi_ioctl(struct scsi_device *dev, int cmd, void __user *arg);
989extern int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *)); 989extern int ata_scsi_queuecmd(struct Scsi_Host *h, struct scsi_cmnd *cmd);
990extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *dev, 990extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *dev,
991 int cmd, void __user *arg); 991 int cmd, void __user *arg);
992extern void ata_sas_port_destroy(struct ata_port *); 992extern void ata_sas_port_destroy(struct ata_port *);