This is in #upstream-fixes... Each libata command is now two lock-ops
less expensive... for free! Should be nice for multi-core SSD users etc.
(not a pull request, Linus, just an FYI)
commit 02ab5c49284c91901cad783921e816297c92ebf8
Author: Jeff Garzik <jeff@xxxxxxxxxx>
Date: Wed Nov 17 01:19:11 2010 -0500
[libata] kill unlock+relock cycle in SCSI queuecommand hook
Now that SCSI's ->queuecommand hook is unlocked, ATA no longer needs
to unlock the SCSI host_lock prior to work, and re-lock the host_lock
once our work is complete.
Signed-off-by: Jeff Garzik <jgarzik@xxxxxxxxxx>
drivers/ata/libata-scsi.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 19835d3..d72340e 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3166,8 +3166,8 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
/**
* ata_scsi_queuecmd - Issue SCSI cdb to libata-managed device
+ * @shost: SCSI host destination for given command
* @cmd: SCSI command to be sent
- * @done: Completion function, called when command is complete
*
* In some cases, this function translates SCSI commands into
* ATA taskfiles, and queues the taskfiles to be sent to
@@ -3183,36 +3183,41 @@ static inline int __ata_scsi_queuecmd(struct scsi_cmnd *scmd,
* Return value from __ata_scsi_queuecmd() if @cmd can be queued,
* 0 otherwise.
*/
-static int ata_scsi_queuecmd_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd *))
+int ata_scsi_queuecmd(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
{
struct ata_port *ap;
struct ata_device *dev;
struct scsi_device *scsidev = cmd->device;
- struct Scsi_Host *shost = scsidev->host;
int rc = 0;
+ unsigned long irq_flags;
- ap = ata_shost_to_port(shost);
+ local_irq_save(irq_flags);
+ spin_lock(shost->host_lock);
+ scsi_cmd_get_serial(shost, cmd);
spin_unlock(shost->host_lock);
+
+ ap = ata_shost_to_port(shost);
+
spin_lock(ap->lock);
ata_scsi_dump_cdb(ap, cmd);
dev = ata_scsi_find_dev(ap, scsidev);
if (likely(dev))
- rc = __ata_scsi_queuecmd(cmd, done, dev);
+ rc = __ata_scsi_queuecmd(cmd, cmd->scsi_done, dev);
else {
cmd->result = (DID_BAD_TARGET << 16);
- done(cmd);
+ cmd->scsi_done(cmd);
}
spin_unlock(ap->lock);
- spin_lock(shost->host_lock);
+
+ local_irq_restore(irq_flags);
+
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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