[PATCH] libata-eh don't waste time retrying media errors

[Mark Lord <kernel@teksavvy.com>]

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ATA and SATA drives have had built-in retries for media errors
for as long as they've been commonplace in computers (early 1990s).

When libata stumbles across a bad sector, it can waste minutes
sitting there doing retry after retry before finally giving up
and letting the higher layers deal with it.

This patch removes retries for media errors only.

Signed-off-by: Mark Lord <mlord@pobox.com>

--- linux-3.3.4/drivers/ata/libata-eh.c	2012-04-27 13:17:35.000000000 -0400
+++ linux/drivers/ata/libata-eh.c	2012-05-01 19:53:55.586811975 -0400
@@ -2121,8 +2121,9 @@
 		/* determine whether the command is worth retrying */
 		if (qc->flags & ATA_QCFLAG_IO ||
 		    (!(qc->err_mask & AC_ERR_INVALID) &&
-		     qc->err_mask != AC_ERR_DEV))
-			qc->flags |= ATA_QCFLAG_RETRY;
+		     !(qc->err_mask & AC_ERR_DEV)))
+			if (!(qc->err_mask & AC_ERR_MEDIA))
+				qc->flags |= ATA_QCFLAG_RETRY;

 		/* accumulate error info */
 		ehc->i.dev = qc->dev;

[-- Attachment #2: 02_libata_sata_dont_retry_media_errors.patch --]
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Prevent libata from retrying bad sectors.
Otherwise a single bad sector gets stuck here for minutes at a time.

--- linux-3.3.4/drivers/ata/libata-eh.c	2012-04-27 13:17:35.000000000 -0400
+++ linux/drivers/ata/libata-eh.c	2012-05-01 19:53:55.586811975 -0400
@@ -2121,8 +2121,9 @@
 		/* determine whether the command is worth retrying */
 		if (qc->flags & ATA_QCFLAG_IO ||
 		    (!(qc->err_mask & AC_ERR_INVALID) &&
-		     qc->err_mask != AC_ERR_DEV))
-			qc->flags |= ATA_QCFLAG_RETRY;
+		     !(qc->err_mask & AC_ERR_DEV)))
+			if (!(qc->err_mask & AC_ERR_MEDIA))
+				qc->flags |= ATA_QCFLAG_RETRY;
 
 		/* accumulate error info */
 		ehc->i.dev = qc->dev;