2 files changed, 37 insertions, 4 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index de2cd61a264d..966abb5f423e 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -980,15 +980,39 @@ unsigned ata_exec_internal(struct ata_device *dev,
         struct ata_port *ap = dev->ap;
         u8 command = tf->command;
         struct ata_queued_cmd *qc;
+        unsigned int tag, preempted_tag;
         DECLARE_COMPLETION(wait);
         unsigned long flags;
         unsigned int err_mask;
 
         spin_lock_irqsave(&ap->host_set->lock, flags);
 
-        qc = ata_qc_new_init(dev);
-        BUG_ON(qc == NULL);
+        /* initialize internal qc */
 
+        /* XXX: Tag 0 is used for drivers with legacy EH as some
+         * drivers choke if any other tag is given.  This breaks
+         * ata_tag_internal() test for those drivers.  Don't use new
+         * EH stuff without converting to it.
+         */
+        if (ap->ops->error_handler)
+                tag = ATA_TAG_INTERNAL;
+        else
+                tag = 0;
+
+        if (test_and_set_bit(tag, &ap->qactive))
+                BUG();
+        qc = ata_qc_from_tag(ap, tag);
+
+        qc->tag = tag;
+        qc->scsicmd = NULL;
+        qc->ap = ap;
+        qc->dev = dev;
+        ata_qc_reinit(qc);
+
+        preempted_tag = ap->active_tag;
+        ap->active_tag = ATA_TAG_POISON;
+
+        /* prepare & issue qc */
         qc->tf = *tf;
         if (cdb)
                 memcpy(qc->cdb, cdb, ATAPI_CDB_LEN);
@@ -1035,6 +1059,7 @@ unsigned ata_exec_internal(struct ata_device *dev,
         err_mask = qc->err_mask;
 
         ata_qc_free(qc);
+        ap->active_tag = preempted_tag;
 
         /* XXX - Some LLDDs (sata_mv) disable port on command failure.
          * Until those drivers are fixed, we detect the condition
@@ -4014,7 +4039,8 @@ static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
         struct ata_queued_cmd *qc = NULL;
         unsigned int i;
 
-        for (i = 0; i < ATA_MAX_QUEUE; i++)
+        /* the last tag is reserved for internal command. */
+        for (i = 0; i < ATA_MAX_QUEUE - 1; i++)
                 if (!test_and_set_bit(i, &ap->qactive)) {
                         qc = ata_qc_from_tag(ap, i);
                         break;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index e5d6d7f8e6dc..5a403e434ff8 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -108,7 +108,9 @@ enum {
         LIBATA_MAX_PRD          = ATA_MAX_PRD / 2,
         ATA_MAX_PORTS           = 8,
         ATA_DEF_QUEUE           = 1,
-        ATA_MAX_QUEUE           = 1,
+        /* tag ATA_MAX_QUEUE - 1 is reserved for internal commands */
+        ATA_MAX_QUEUE           = 2,
+        ATA_TAG_INTERNAL        = ATA_MAX_QUEUE - 1,
         ATA_MAX_SECTORS         = 200,  /* FIXME */
         ATA_MAX_BUS             = 2,
         ATA_DEF_BUSY_WAIT       = 10000,
@@ -717,6 +719,11 @@ static inline unsigned int ata_tag_valid(unsigned int tag)
         return (tag < ATA_MAX_QUEUE) ? 1 : 0;
 }
 
+static inline unsigned int ata_tag_internal(unsigned int tag)
+{
+        return tag == ATA_MAX_QUEUE - 1;
+}
+
 static inline unsigned int ata_class_enabled(unsigned int class)
 {
         return class == ATA_DEV_ATA || class == ATA_DEV_ATAPI;