Commit c331eb04 authored May 30, 2006 by NeilBrown Committed by Linus Torvalds May 31, 2006

[PATCH] md: Fix badness in sysfs_notify caused by md_new_event



From: NeilBrown <neilb@suse.de>

If an error is reported by a drive in a RAID array (which is done via
bi_end_io - in interrupt context), we call md_error and md_new_event which
calls sysfs_notify.  However sysfs_notify grabs a mutex and so cannot be
called in interrupt context.

This patch just creates a variant of md_new_event which avoids the sysfs
call, and uses that.  A better fix for later is to arrange for the event to
be called from user-context.

Note: avoiding the sysfs call isn't a problem as an error will not, by
itself, modify the sync_action attribute.  (We do still need to
wake_up(&md_event_waiters) as an error by itself will modify /proc/mdstat).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent a835fa79

drivers/md/md.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -167,6 +167,15 @@ void md_new_event(mddev_t *mddev)
		}
		EXPORT_SYMBOL_GPL(md_new_event);

		/* Alternate version that can be called from interrupts
		* when calling sysfs_notify isn't needed.
		*/
		void md_new_event_inintr(mddev_t *mddev)
		{
		atomic_inc(&md_event_count);
		wake_up(&md_event_waiters);
		}

		/*
		* Enables to iterate over all existing md arrays
		* all_mddevs_lock protects this list.
		@@ -4149,7 +4158,7 @@ void md_error(mddev_t mddev, mdk_rdev_t rdev)
		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
		md_wakeup_thread(mddev->thread);
		md_new_event(mddev);
		md_new_event_inintr(mddev);
		}

		/* seq_file implementation /proc/mdstat */

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