Commit c331eb04 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[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: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent a835fa79
......@@ -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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