libata: implement AC_ERR_NCQ

When an NCQ command fails, all commands in flight are aborted and the
offending one is reported using log page 10h.  Depending on controller
characteristics and LLD implementation, all commands may appear as
having a device error due to shared TF status making it hard to
determine what's actually going on.

This patch adds AC_ERR_NCQ, marks the command reported by log page 10h
with it and print extra "<F>" after the error report for the command
to help distinguishing the offending command.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-eh.c

@@ -1195,7 +1195,7 @@ static void ata_eh_analyze_ncq_error(struct ata_port *ap)
 	/* we've got the perpetrator, condemn it */
 	qc = __ata_qc_from_tag(ap, tag);
 	memcpy(&qc->result_tf, &tf, sizeof(tf));
-	qc->err_mask |= AC_ERR_DEV;
+	qc->err_mask |= AC_ERR_DEV | AC_ERR_NCQ;
 	ehc->i.err_mask &= ~AC_ERR_DEV;
 }
 
@@ -1616,7 +1616,7 @@ static void ata_eh_report(struct ata_port *ap)
 			"cmd %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
 			"tag %d cdb 0x%x data %u %s\n         "
 			"res %02x/%02x:%02x:%02x:%02x:%02x/%02x:%02x:%02x:%02x:%02x/%02x "
-			"Emask 0x%x (%s)\n",
+			"Emask 0x%x (%s)%s\n",
 			cmd->command, cmd->feature, cmd->nsect,
 			cmd->lbal, cmd->lbam, cmd->lbah,
 			cmd->hob_feature, cmd->hob_nsect,
@@ -1627,7 +1627,8 @@ static void ata_eh_report(struct ata_port *ap)
 			res->lbal, res->lbam, res->lbah,
 			res->hob_feature, res->hob_nsect,
 			res->hob_lbal, res->hob_lbam, res->hob_lbah,
-			res->device, qc->err_mask, ata_err_string(qc->err_mask));
+			res->device, qc->err_mask, ata_err_string(qc->err_mask),
+			qc->err_mask & AC_ERR_NCQ ? " <F>" : "");
 	}
 }
 

include/linux/libata.h

@@ -323,6 +323,7 @@ enum ata_completion_errors {
 	AC_ERR_INVALID		= (1 << 7), /* invalid argument */
 	AC_ERR_OTHER		= (1 << 8), /* unknown */
 	AC_ERR_NODEV_HINT	= (1 << 9), /* polling device detection hint */
+	AC_ERR_NCQ		= (1 << 10), /* marker for offending NCQ qc */
 };
 
 /* forward declarations */