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authorTejun Heo <tj@kernel.org>2011-05-25 13:19:39 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-08-08 10:23:08 -0700
commit3da5a14f740df9eef668edd4a446824da2a6c299 (patch)
treee875bf22a10c263a7c534df8ed1674fef148d5eb /drivers
parent49d571cd91d115bf051aa14bc15376c5095217b6 (diff)
downloadlinux-linaro-stable-3da5a14f740df9eef668edd4a446824da2a6c299.tar.gz
libata: fix unexpectedly frozen port after ata_eh_reset()
commit 8c56cacc724c7650b893d43068fa66044aa29a61 upstream. To work around controllers which can't properly plug events while reset, ata_eh_reset() clears error states and ATA_PFLAG_EH_PENDING after reset but before RESET is marked done. As reset is the final recovery action and full verification of devices including onlineness and classfication match is done afterwards, this shouldn't lead to lost devices or missed hotplug events. Unfortunately, it forgot to thaw the port when clearing EH_PENDING, so if the condition happens after resetting an empty port, the port could be left frozen and EH will end without thawing it, making the port unresponsive to further hotplug events. Thaw if the port is frozen after clearing EH_PENDING. This problem is reported by Bruce Stenning in the following thread. http://thread.gmane.org/gmane.linux.kernel/1123265 stable: I think we should weather this patch a bit longer in -rcX before sending it to -stable. Please wait at least a month after this patch makes upstream. Thanks. -v2: Fixed spelling in the comment per Dave Howorth. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Bruce Stenning <b.stenning@indigovision.com> Cc: Dave Howorth <dhoworth@mrc-lmb.cam.ac.uk> Signed-off-by: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/ata/libata-eh.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index fa9bed06b397..e5bdb9bb0a9e 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2707,10 +2707,11 @@ int ata_eh_reset(struct ata_link *link, int classify,
}
/*
- * Some controllers can't be frozen very well and may set
- * spuruious error conditions during reset. Clear accumulated
- * error information. As reset is the final recovery action,
- * nothing is lost by doing this.
+ * Some controllers can't be frozen very well and may set spurious
+ * error conditions during reset. Clear accumulated error
+ * information and re-thaw the port if frozen. As reset is the
+ * final recovery action and we cross check link onlineness against
+ * device classification later, no hotplug event is lost by this.
*/
spin_lock_irqsave(link->ap->lock, flags);
memset(&link->eh_info, 0, sizeof(link->eh_info));
@@ -2719,6 +2720,9 @@ int ata_eh_reset(struct ata_link *link, int classify,
ap->pflags &= ~ATA_PFLAG_EH_PENDING;
spin_unlock_irqrestore(link->ap->lock, flags);
+ if (ap->pflags & ATA_PFLAG_FROZEN)
+ ata_eh_thaw_port(ap);
+
/*
* Make sure onlineness and classification result correspond.
* Hotplug could have happened during reset and some