[PATCH] libata: implement ATA_FLAG_IN_EH port flag

ATA_FLAG_IN_EH flag is set on entry to EH and cleared on completion.
This patch just sets and clears the flag.  Following patches will
build normal qc execution / EH synchronization aroung this flag.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

2 files changed, 11 insertions, 0 deletions

diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 2d328b3af067..3a4f40b251fb 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -735,6 +735,11 @@ int ata_scsi_error(struct Scsi_Host *host)
 
         DPRINTK("ENTER\n");
 
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+        assert(!(ap->flags & ATA_FLAG_IN_EH));
+        ap->flags |= ATA_FLAG_IN_EH;
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
         ap = (struct ata_port *) &host->hostdata[0];
         ap->ops->eng_timeout(ap);
 
@@ -742,6 +747,10 @@ int ata_scsi_error(struct Scsi_Host *host)
 
         scsi_eh_flush_done_q(&ap->eh_done_q);
 
+        spin_lock_irqsave(&ap->host_set->lock, flags);
+        ap->flags &= ~ATA_FLAG_IN_EH;
+        spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
         DPRINTK("EXIT\n");
         return 0;
 }
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 474cdfa35d1e..55176df403a5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -162,6 +162,8 @@ enum {
         ATA_FLAG_PIO_LBA48      = (1 << 13), /* Host DMA engine is LBA28 only */
         ATA_FLAG_IRQ_MASK       = (1 << 14), /* Mask IRQ in PIO xfers */
 
+        ATA_FLAG_IN_EH          = (1 << 15), /* EH in progress */
+
         ATA_QCFLAG_ACTIVE       = (1 << 1), /* cmd not yet ack'd to scsi lyer */
         ATA_QCFLAG_SG           = (1 << 3), /* have s/g table? */
         ATA_QCFLAG_SINGLE       = (1 << 4), /* no s/g, just a single buffer */