[PATCH] libata: add ATA_QCFLAG_EH_SCHEDULED

Add ATA_QCFLAG_EH_SCHEDULED.  If this flag is set, the qc is owned by
EH and normal completion path is not allowed to finish it.  This patch
doesn't actually use this flag.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

drivers/scsi/libata-core.c

@@ -3620,19 +3620,7 @@ void ata_qc_free(struct ata_queued_cmd *qc)
 	}
 }
 
-/**
- *	ata_qc_complete - Complete an active ATA command
- *	@qc: Command to complete
- *	@err_mask: ATA Status register contents
- *
- *	Indicate to the mid and upper layers that an ATA
- *	command has completed, with either an ok or not-ok status.
- *
- *	LOCKING:
- *	spin_lock_irqsave(host_set lock)
- */
-
-void ata_qc_complete(struct ata_queued_cmd *qc)
+inline void __ata_qc_complete(struct ata_queued_cmd *qc)
 {
 	assert(qc != NULL);	/* ata_qc_from_tag _might_ return NULL */
 	assert(qc->flags & ATA_QCFLAG_ACTIVE);
@@ -3650,6 +3638,25 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
 	qc->complete_fn(qc);
 }
 
+/**
+ *	ata_qc_complete - Complete an active ATA command
+ *	@qc: Command to complete
+ *	@err_mask: ATA Status register contents
+ *
+ *	Indicate to the mid and upper layers that an ATA
+ *	command has completed, with either an ok or not-ok status.
+ *
+ *	LOCKING:
+ *	spin_lock_irqsave(host_set lock)
+ */
+void ata_qc_complete(struct ata_queued_cmd *qc)
+{
+	if (unlikely(qc->flags & ATA_QCFLAG_EH_SCHEDULED))
+		return;
+
+	__ata_qc_complete(qc);
+}
+
 static inline int ata_should_dma_map(struct ata_queued_cmd *qc)
 {
 	struct ata_port *ap = qc->ap;

drivers/scsi/libata-scsi.c

@@ -770,7 +770,7 @@ static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
 
 	spin_lock_irqsave(&ap->host_set->lock, flags);
 	qc->scsidone = ata_eh_scsidone;
-	ata_qc_complete(qc);
+	__ata_qc_complete(qc);
 	assert(!ata_tag_valid(qc->tag));
 	spin_unlock_irqrestore(&ap->host_set->lock, flags);
 

drivers/scsi/libata.h

@@ -46,6 +46,7 @@ extern struct ata_queued_cmd *ata_qc_new_init(struct ata_port *ap,
 extern int ata_rwcmd_protocol(struct ata_queued_cmd *qc);
 extern void ata_qc_free(struct ata_queued_cmd *qc);
 extern unsigned int ata_qc_issue(struct ata_queued_cmd *qc);
+extern void __ata_qc_complete(struct ata_queued_cmd *qc);
 extern int ata_check_atapi_dma(struct ata_queued_cmd *qc);
 extern void ata_dev_select(struct ata_port *ap, unsigned int device,
                            unsigned int wait, unsigned int can_sleep);

include/linux/libata.h

@@ -169,6 +169,7 @@ enum {
 	ATA_QCFLAG_SG		= (1 << 3), /* have s/g table? */
 	ATA_QCFLAG_SINGLE	= (1 << 4), /* no s/g, just a single buffer */
 	ATA_QCFLAG_DMAMAP	= ATA_QCFLAG_SG | ATA_QCFLAG_SINGLE,
+	ATA_QCFLAG_EH_SCHEDULED = (1 << 5), /* EH scheduled */
 
 	/* various lengths of time */
 	ATA_TMOUT_EDD		= 5 * HZ,	/* heuristic */