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esp_scsi: fix reset cleanup spinlock recursion

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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: Maciej W. Rozycki <macro@linux-mips.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Maciej W. Rozycki 2007-12-10 15:49:31 -08:00 committed by Linus Torvalds
parent 794e64d5e9
commit 522939d45c
3 changed files with 34 additions and 4 deletions
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4
drivers/scsi/esp_scsi.c
View File

@ -2026,8 +2026,8 @@ static void esp_reset_cleanup(struct esp *esp)
tp->flags |= ESP_TGT_CHECK_NEGO;
if (tp->starget)
starget_for_each_device(tp->starget, NULL,
esp_clear_hold);
__starget_for_each_device(tp->starget, NULL,
esp_clear_hold);
}
esp->flags &= ~ESP_FLAG_RESETTING;
}

31
drivers/scsi/scsi.c
View File

@ -896,11 +896,11 @@ 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.
*/
void starget_for_each_device(struct scsi_target *starget, void * data,
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);
@ -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

3
include/scsi/scsi_device.h
View File

@ -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 *,