[BLOCK] update SCSI to use new blk_ordered for barriers

All ordered request related stuff delegated to HLD.  Midlayer
now doens't deal with ordered setting or prepare_flush
callback.  sd.c updated to deal with blk_queue_ordered
setting.  Currently, ordered tag isn't used as SCSI midlayer
cannot guarantee request ordering.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>

3 files changed, 20 insertions, 93 deletions

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 5b9c2c5a7f0..66783c860a1 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -347,17 +347,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
         shost->cmd_per_lun = sht->cmd_per_lun;
         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
         shost->use_clustering = sht->use_clustering;
-        shost->ordered_flush = sht->ordered_flush;
         shost->ordered_tag = sht->ordered_tag;
 
-        /*
-         * hosts/devices that do queueing must support ordered tags
-         */
-        if (shost->can_queue > 1 && shost->ordered_flush) {
-                printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
-                shost->ordered_flush = 0;
-        }
-
         if (sht->max_host_blocked)
                 shost->max_host_blocked = sht->max_host_blocked;
         else
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 53551f1dfe2..7a38b101976 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -932,9 +932,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes,
         int sense_valid = 0;
         int sense_deferred = 0;
 
-        if (blk_complete_barrier_rq(q, req, good_bytes >> 9))
-                return;
-
         /*
          * Free up any indirection buffers we allocated for DMA purposes. 
          * For the case of a READ, we need to copy the data out of the
@@ -1199,38 +1196,6 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
         return BLKPREP_KILL;
 }
 
-static int scsi_prepare_flush_fn(request_queue_t *q, struct request *rq)
-{
-        struct scsi_device *sdev = q->queuedata;
-        struct scsi_driver *drv;
-
-        if (sdev->sdev_state == SDEV_RUNNING) {
-                drv = *(struct scsi_driver **) rq->rq_disk->private_data;
-
-                if (drv->prepare_flush)
-                        return drv->prepare_flush(q, rq);
-        }
-
-        return 0;
-}
-
-static void scsi_end_flush_fn(request_queue_t *q, struct request *rq)
-{
-        struct scsi_device *sdev = q->queuedata;
-        struct request *flush_rq = rq->end_io_data;
-        struct scsi_driver *drv;
-
-        if (flush_rq->errors) {
-                printk("scsi: barrier error, disabling flush support\n");
-                blk_queue_ordered(q, QUEUE_ORDERED_NONE);
-        }
-
-        if (sdev->sdev_state == SDEV_RUNNING) {
-                drv = *(struct scsi_driver **) rq->rq_disk->private_data;
-                drv->end_flush(q, rq);
-        }
-}
-
 static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk,
                                sector_t *error_sector)
 {
@@ -1703,17 +1668,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
         blk_queue_segment_boundary(q, shost->dma_boundary);
         blk_queue_issue_flush_fn(q, scsi_issue_flush_fn);
 
-        /*
-         * ordered tags are superior to flush ordering
-         */
-        if (shost->ordered_tag)
-                blk_queue_ordered(q, QUEUE_ORDERED_TAG);
-        else if (shost->ordered_flush) {
-                blk_queue_ordered(q, QUEUE_ORDERED_FLUSH);
-                q->prepare_flush_fn = scsi_prepare_flush_fn;
-                q->end_flush_fn = scsi_end_flush_fn;
-        }
-
         if (!shost->use_clustering)
                 clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
         return q;
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index d651150ee76..2eefc9eb5da 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -121,8 +121,7 @@ static void sd_shutdown(struct device *dev);
 static void sd_rescan(struct device *);
 static int sd_init_command(struct scsi_cmnd *);
 static int sd_issue_flush(struct device *, sector_t *);
-static void sd_end_flush(request_queue_t *, struct request *);
-static int sd_prepare_flush(request_queue_t *, struct request *);
+static void sd_prepare_flush(request_queue_t *, struct request *);
 static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
                              unsigned char *buffer);
 
@@ -137,8 +136,6 @@ static struct scsi_driver sd_template = {
         .rescan                 = sd_rescan,
         .init_command           = sd_init_command,
         .issue_flush            = sd_issue_flush,
-        .prepare_flush          = sd_prepare_flush,
-        .end_flush              = sd_end_flush,
 };
 
 /*
@@ -729,42 +726,13 @@ static int sd_issue_flush(struct device *dev, sector_t *error_sector)
         return ret;
 }
 
-static void sd_end_flush(request_queue_t *q, struct request *flush_rq)
+static void sd_prepare_flush(request_queue_t *q, struct request *rq)
 {
-        struct request *rq = flush_rq->end_io_data;
-        struct scsi_cmnd *cmd = rq->special;
-        unsigned int bytes = rq->hard_nr_sectors << 9;
-
-        if (!flush_rq->errors) {
-                spin_unlock(q->queue_lock);
-                scsi_io_completion(cmd, bytes, 0);
-                spin_lock(q->queue_lock);
-        } else if (blk_barrier_postflush(rq)) {
-                spin_unlock(q->queue_lock);
-                scsi_io_completion(cmd, 0, bytes);
-                spin_lock(q->queue_lock);
-        } else {
-                /*
-                 * force journal abort of barriers
-                 */
-                end_that_request_first(rq, -EOPNOTSUPP, rq->hard_nr_sectors);
-                end_that_request_last(rq, -EOPNOTSUPP);
-        }
-}
-
-static int sd_prepare_flush(request_queue_t *q, struct request *rq)
-{
-        struct scsi_device *sdev = q->queuedata;
-        struct scsi_disk *sdkp = dev_get_drvdata(&sdev->sdev_gendev);
-
-        if (!sdkp || !sdkp->WCE)
-                return 0;
-
         memset(rq->cmd, 0, sizeof(rq->cmd));
-        rq->flags |= REQ_BLOCK_PC | REQ_SOFTBARRIER;
+        rq->flags |= REQ_BLOCK_PC;
         rq->timeout = SD_TIMEOUT;
         rq->cmd[0] = SYNCHRONIZE_CACHE;
-        return 1;
+        rq->cmd_len = 10;
 }
 
 static void sd_rescan(struct device *dev)
@@ -1462,6 +1430,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
         struct scsi_disk *sdkp = scsi_disk(disk);
         struct scsi_device *sdp = sdkp->device;
         unsigned char *buffer;
+        unsigned ordered;
 
         SCSI_LOG_HLQUEUE(3, printk("sd_revalidate_disk: disk=%s\n", disk->disk_name));
 
@@ -1498,7 +1467,20 @@ static int sd_revalidate_disk(struct gendisk *disk)
                 sd_read_write_protect_flag(sdkp, disk->disk_name, buffer);
                 sd_read_cache_type(sdkp, disk->disk_name, buffer);
         }
-                
+
+        /*
+         * We now have all cache related info, determine how we deal
+         * with ordered requests.  Note that as the current SCSI
+         * dispatch function can alter request order, we cannot use
+         * QUEUE_ORDERED_TAG_* even when ordered tag is supported.
+         */
+        if (sdkp->WCE)
+                ordered = QUEUE_ORDERED_DRAIN_FLUSH;
+        else
+                ordered = QUEUE_ORDERED_DRAIN;
+
+        blk_queue_ordered(sdkp->disk->queue, ordered, sd_prepare_flush);
+
         set_capacity(disk, sdkp->capacity);
         kfree(buffer);
 
@@ -1598,6 +1580,7 @@ static int sd_probe(struct device *dev)
         strcpy(gd->devfs_name, sdp->devfs_name);
 
         gd->private_data = &sdkp->driver;
+        gd->queue = sdkp->device->request_queue;
 
         sd_revalidate_disk(gd);
 
@@ -1605,7 +1588,6 @@ static int sd_probe(struct device *dev)
         gd->flags = GENHD_FL_DRIVERFS;
         if (sdp->removable)
                 gd->flags |= GENHD_FL_REMOVABLE;
-        gd->queue = sdkp->device->request_queue;
 
         dev_set_drvdata(dev, sdkp);
         add_disk(gd);