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: 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>

authored by

Maciej W. Rozycki and committed by

Linus Torvalds 18 years ago 522939d4 794e64d5

+34 -4

3 changed files

expand all

drivers

scsi

esp_scsi.c

scsi.c

include

scsi

scsi_device.h

+2 -2

drivers/scsi/esp_scsi.c

··· 2026 2026 tp->flags |= ESP_TGT_CHECK_NEGO; 2027 2027 2028 2028 if (tp->starget) 2029 - starget_for_each_device(tp->starget, NULL, 2030 - esp_clear_hold); 2029 + __starget_for_each_device(tp->starget, NULL, 2030 + esp_clear_hold); 2031 2031 } 2032 2032 esp->flags &= ~ESP_FLAG_RESETTING; 2033 2033 }

+29 -2

drivers/scsi/scsi.c

··· 896 896 * starget_for_each_device - helper to walk all devices of a target 897 897 * @starget: target whose devices we want to iterate over. 898 898 * 899 - * This traverses over each devices of @shost. The devices have 899 + * This traverses over each device of @starget. The devices have 900 900 * a reference that must be released by scsi_host_put when breaking 901 901 * out of the loop. 902 902 */ 903 - void starget_for_each_device(struct scsi_target *starget, void * data, 903 + void starget_for_each_device(struct scsi_target *starget, void *data, 904 904 void (*fn)(struct scsi_device *, void *)) 905 905 { 906 906 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); ··· 913 913 } 914 914 } 915 915 EXPORT_SYMBOL(starget_for_each_device); 916 + 917 + /** 918 + * __starget_for_each_device - helper to walk all devices of a target 919 + * (UNLOCKED) 920 + * @starget: target whose devices we want to iterate over. 921 + * 922 + * This traverses over each device of @starget. It does _not_ 923 + * take a reference on the scsi_device, so the whole loop must be 924 + * protected by shost->host_lock. 925 + * 926 + * Note: The only reason why drivers would want to use this is because 927 + * they need to access the device list in irq context. Otherwise you 928 + * really want to use starget_for_each_device instead. 929 + **/ 930 + void __starget_for_each_device(struct scsi_target *starget, void *data, 931 + void (*fn)(struct scsi_device *, void *)) 932 + { 933 + struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 934 + struct scsi_device *sdev; 935 + 936 + __shost_for_each_device(sdev, shost) { 937 + if ((sdev->channel == starget->channel) && 938 + (sdev->id == starget->id)) 939 + fn(sdev, data); 940 + } 941 + } 942 + EXPORT_SYMBOL(__starget_for_each_device); 916 943 917 944 /** 918 945 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)

include/scsi/scsi_device.h

··· 242 242 uint); 243 243 extern void starget_for_each_device(struct scsi_target *, void *, 244 244 void (*fn)(struct scsi_device *, void *)); 245 + extern void __starget_for_each_device(struct scsi_target *, void *, 246 + void (*fn)(struct scsi_device *, 247 + void *)); 245 248 246 249 /* only exposed to implement shost_for_each_device */ 247 250 extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,

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