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Commit 522939d4 authored by Maciej W. Rozycki's avatar Maciej W. Rozycki Committed by Linus Torvalds
Browse files

esp_scsi: fix reset cleanup spinlock recursion 



The esp_reset_cleanup() function is called with the host lock held and
invokes starget_for_each_device() which wants to take it too.  Here is a
fix along the lines of shost_for_each_device()/__shost_for_each_device()
adding a __starget_for_each_device() counterpart which assumes the lock
has already been taken.

Eventually, I think the driver should get modified so that more work is
done as a softirq rather than in the interrupt context, but for now it
fixes a bug that causes the spinlock debugger to fire.

While at it, it fixes a small number of cosmetic problems with
starget_for_each_device() too.

Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 794e64d5

drivers/scsi/esp_scsi.c

+2 −2
Original line number Diff line number Diff line
@@ -2026,7 +2026,7 @@ static void esp_reset_cleanup(struct esp *esp) 
		tp->flags |= ESP_TGT_CHECK_NEGO;



		if (tp->starget)

			starget_for_each_device(tp->starget, NULL,

			__starget_for_each_device(tp->starget, NULL,

						  esp_clear_hold);

	}

	esp->flags &= ~ESP_FLAG_RESETTING;

drivers/scsi/scsi.c

+29 −2
Original line number Diff line number Diff line
@@ -896,7 +896,7 @@ EXPORT_SYMBOL(__scsi_iterate_devices); 
 * starget_for_each_device  -  helper to walk all devices of a target

 * @starget:	target whose devices we want to iterate over.

 *

 * This traverses over each devices of @shost.  The devices have

 * This traverses over each device of @starget.  The devices have

 * a reference that must be released by scsi_host_put when breaking

 * out of the loop.

 */
@@ -914,6 +914,33 @@ void starget_for_each_device(struct scsi_target *starget, void * data, 
}

EXPORT_SYMBOL(starget_for_each_device);



/**

 * __starget_for_each_device  -  helper to walk all devices of a target

 *				 (UNLOCKED)

 * @starget:	target whose devices we want to iterate over.

 *

 * This traverses over each device of @starget.  It does _not_

 * take a reference on the scsi_device, so the whole loop must be

 * protected by shost->host_lock.

 *

 * Note:  The only reason why drivers would want to use this is because

 * they need to access the device list in irq context.  Otherwise you

 * really want to use starget_for_each_device instead.

 **/

void __starget_for_each_device(struct scsi_target *starget, void *data,

			       void (*fn)(struct scsi_device *, void *))

{

	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);

	struct scsi_device *sdev;



	__shost_for_each_device(sdev, shost) {

		if ((sdev->channel == starget->channel) &&

		    (sdev->id == starget->id))

			fn(sdev, data);

	}

}

EXPORT_SYMBOL(__starget_for_each_device);



/**

 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)

 * @starget:	SCSI target pointer

include/scsi/scsi_device.h

+3 −0
Original line number Diff line number Diff line
@@ -242,6 +242,9 @@ extern struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *, 
							  uint);

extern void starget_for_each_device(struct scsi_target *, void *,

		     void (*fn)(struct scsi_device *, void *));

extern void __starget_for_each_device(struct scsi_target *, void *,

				      void (*fn)(struct scsi_device *,

						 void *));



/* only exposed to implement shost_for_each_device */

extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,