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authorTejun Heo <tj@kernel.org>2011-05-25 07:19:39 -0400
committerJeff Garzik <jgarzik@pobox.com>2011-06-07 15:55:55 -0400
commit8c56cacc724c7650b893d43068fa66044aa29a61 (patch)
tree57bffa9525cd9403ef0a288508e774acf2e2920f /drivers/ata
parent59c5f46fbe01a00eedf54a23789634438bb80603 (diff)
libata: fix unexpectedly frozen port after ata_eh_reset()
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: stable@kernel.org Cc: Dave Howorth <dhoworth@mrc-lmb.cam.ac.uk> Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'drivers/ata')
-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 dfb6e9d3d759..7f099d6e4e0b 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2802,10 +2802,11 @@ int ata_eh_reset(struct ata_link *link, int classify,
2802 } 2802 }
2803 2803
2804 /* 2804 /*
2805 * Some controllers can't be frozen very well and may set 2805 * Some controllers can't be frozen very well and may set spurious
2806 * spuruious error conditions during reset. Clear accumulated 2806 * error conditions during reset. Clear accumulated error
2807 * error information. As reset is the final recovery action, 2807 * information and re-thaw the port if frozen. As reset is the
2808 * nothing is lost by doing this. 2808 * final recovery action and we cross check link onlineness against
2809 * device classification later, no hotplug event is lost by this.
2809 */ 2810 */
2810 spin_lock_irqsave(link->ap->lock, flags); 2811 spin_lock_irqsave(link->ap->lock, flags);
2811 memset(&link->eh_info, 0, sizeof(link->eh_info)); 2812 memset(&link->eh_info, 0, sizeof(link->eh_info));
@@ -2814,6 +2815,9 @@ int ata_eh_reset(struct ata_link *link, int classify,
2814 ap->pflags &= ~ATA_PFLAG_EH_PENDING; 2815 ap->pflags &= ~ATA_PFLAG_EH_PENDING;
2815 spin_unlock_irqrestore(link->ap->lock, flags); 2816 spin_unlock_irqrestore(link->ap->lock, flags);
2816 2817
2818 if (ap->pflags & ATA_PFLAG_FROZEN)
2819 ata_eh_thaw_port(ap);
2820
2817 /* 2821 /*
2818 * Make sure onlineness and classification result correspond. 2822 * Make sure onlineness and classification result correspond.
2819 * Hotplug could have happened during reset and some 2823 * Hotplug could have happened during reset and some