James Bottomley wrote:
> This is the second half of the execute_process_context() API addition:
> an actual user
I just tried this out on my ppc64 box. I recently noticed that
the target reaping via workqueue change that went in not too long ago
resulted in *really* slow user initiated wildcard scans for ipr
adapters - in the neighborhood of 6 minutes... Your patch brings
that back down to 8 seconds.
Brian
>
> James
>
> --
>
> [SCSI] fix wrong context bugs in SCSI
>
> There's a bug in releasing scsi_device where the release function
> actually frees the block queue. However, the block queue release
> calls flush_work(), which requires process context (the scsi_device
> structure may release from irq context). Update the release function
> to invoke via the execute_in_process_context() API.
>
> Also clean up the scsi_target structure releasing via this API.
>
> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxxxxxxx>
>
> Index: BUILD-2.6/drivers/scsi/scsi_scan.c
> ===================================================================
> --- BUILD-2.6.orig/drivers/scsi/scsi_scan.c 2006-02-07 09:23:44.000000000 -0600
> +++ BUILD-2.6/drivers/scsi/scsi_scan.c 2006-02-07 11:35:46.000000000 -0600
> @@ -385,19 +385,12 @@
> return found_target;
> }
>
> -struct work_queue_wrapper {
> - struct work_struct work;
> - struct scsi_target *starget;
> -};
> -
> -static void scsi_target_reap_work(void *data) {
> - struct work_queue_wrapper *wqw = (struct work_queue_wrapper *)data;
> - struct scsi_target *starget = wqw->starget;
> +static void scsi_target_reap_usercontext(void *data)
> +{
> + struct scsi_target *starget = data;
> struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
> unsigned long flags;
>
> - kfree(wqw);
> -
> spin_lock_irqsave(shost->host_lock, flags);
>
> if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
> @@ -426,18 +419,7 @@
> */
> void scsi_target_reap(struct scsi_target *starget)
> {
> - struct work_queue_wrapper *wqw =
> - kzalloc(sizeof(struct work_queue_wrapper), GFP_ATOMIC);
> -
> - if (!wqw) {
> - starget_printk(KERN_ERR, starget,
> - "Failed to allocate memory in scsi_reap_target()\n");
> - return;
> - }
> -
> - INIT_WORK(&wqw->work, scsi_target_reap_work, wqw);
> - wqw->starget = starget;
> - schedule_work(&wqw->work);
> + execute_in_process_context(scsi_target_reap_usercontext, starget);
> }
>
> /**
> Index: BUILD-2.6/drivers/scsi/scsi_sysfs.c
> ===================================================================
> --- BUILD-2.6.orig/drivers/scsi/scsi_sysfs.c 2006-02-07 09:23:44.000000000 -0600
> +++ BUILD-2.6/drivers/scsi/scsi_sysfs.c 2006-02-07 11:35:08.000000000 -0600
> @@ -217,8 +217,9 @@
> put_device(&sdev->sdev_gendev);
> }
>
> -static void scsi_device_dev_release(struct device *dev)
> +static void scsi_device_dev_release_usercontext(void *data)
> {
> + struct device *dev = data;
> struct scsi_device *sdev;
> struct device *parent;
> struct scsi_target *starget;
> @@ -237,6 +238,7 @@
>
> if (sdev->request_queue) {
> sdev->request_queue->queuedata = NULL;
> + /* user context needed to free queue */
> scsi_free_queue(sdev->request_queue);
> /* temporary expedient, try to catch use of queue lock
> * after free of sdev */
> @@ -252,6 +254,11 @@
> put_device(parent);
> }
>
> +static void scsi_device_dev_release(struct device *dev)
> +{
> + execute_in_process_context(scsi_device_dev_release_usercontext, dev);
> +}
> +
> static struct class sdev_class = {
> .name = "scsi_device",
> .release = scsi_device_cls_release,
>
>
> -
> : send the line "unsubscribe linux-scsi" in
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>
--
Brian King
eServer Storage I/O
IBM Linux Technology Center
-
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