I thought I'd take a crack at removing the host lock from uas. I think
I can now switch to using GFP_NOIO (since interrupts are enabled by
scsi_request_fn()), and I have to use _irq spinlocks to protect the list
that is modified from interrupt context (same reason :-).
Comments?
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 5b6bbae..9e881cd 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1443,7 +1443,7 @@ static void scsi_softirq_done(struct request *rq)
*
* Returns: Nothing
*
- * Lock status: IO request lock assumed to be held when called.
+ * Lock status: request queue lock held, interrupts disabled
*/
static void scsi_request_fn(struct request_queue *q)
{
@@ -1530,10 +1530,6 @@ static void scsi_request_fn(struct request_queue *q)
scsi_target(sdev)->target_busy++;
shost->host_busy++;
- /*
- * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will
- * take the lock again.
- */
spin_unlock_irq(shost->host_lock);
/*
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 23f0dd9..a2cff4b 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -433,8 +433,7 @@ static int uas_submit_urbs(struct scsi_cmnd *cmnd,
return 0;
}
-static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
- void (*done)(struct scsi_cmnd *))
+static int uas_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd)
{
struct scsi_device *sdev = cmnd->device;
struct uas_dev_info *devinfo = sdev->hostdata;
@@ -453,8 +452,6 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
cmdinfo->stream = 1;
}
- cmnd->scsi_done = done;
-
cmdinfo->state = ALLOC_STATUS_URB | SUBMIT_STATUS_URB |
ALLOC_CMD_URB | SUBMIT_CMD_URB;
@@ -475,24 +472,22 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
cmdinfo->stream = 0;
}
- err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
+ err = uas_submit_urbs(cmnd, devinfo, GFP_NOIO);
if (err) {
/* If we did nothing, give up now */
if (cmdinfo->state & SUBMIT_STATUS_URB) {
usb_free_urb(cmdinfo->status_urb);
return SCSI_MLQUEUE_DEVICE_BUSY;
}
- spin_lock(&uas_work_lock);
+ spin_lock_irq(&uas_work_lock);
list_add_tail(&cmdinfo->list, &uas_work_list);
- spin_unlock(&uas_work_lock);
+ spin_unlock_irq(&uas_work_lock);
schedule_work(&uas_work);
}
return 0;
}
-static DEF_SCSI_QCMD(uas_queuecommand)
-
static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
{
struct scsi_device *sdev = cmnd->device;
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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