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Subject[PATCH 02/10] xen/blkfront: drop legacy block layer support
Date
As Christoph suggested, remove the legacy support similar to most
drivers coverted (virtio, mtip, and nvme).

Signed-off-by: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
---
drivers/block/xen-blkfront.c | 167 +++++++++----------------------------------
1 file changed, 32 insertions(+), 135 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 13e6178..3589436 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -135,7 +135,6 @@ struct blkfront_info
unsigned int max_indirect_segments;
int is_ready;
struct blk_mq_tag_set tag_set;
- int feature_multiqueue;
};

static unsigned int nr_minors;
@@ -606,54 +605,6 @@ static inline bool blkif_request_flush_invalid(struct request *req,
!(info->feature_flush & REQ_FUA)));
}

-/*
- * do_blkif_request
- * read a block; request is in a request queue
- */
-static void do_blkif_request(struct request_queue *rq)
-{
- struct blkfront_info *info = NULL;
- struct request *req;
- int queued;
-
- pr_debug("Entered do_blkif_request\n");
-
- queued = 0;
-
- while ((req = blk_peek_request(rq)) != NULL) {
- info = req->rq_disk->private_data;
-
- if (RING_FULL(&info->ring))
- goto wait;
-
- blk_start_request(req);
-
- if (blkif_request_flush_invalid(req, info)) {
- __blk_end_request_all(req, -EOPNOTSUPP);
- continue;
- }
-
- pr_debug("do_blk_req %p: cmd %p, sec %lx, "
- "(%u/%u) [%s]\n",
- req, req->cmd, (unsigned long)blk_rq_pos(req),
- blk_rq_cur_sectors(req), blk_rq_sectors(req),
- rq_data_dir(req) ? "write" : "read");
-
- if (blkif_queue_request(req)) {
- blk_requeue_request(rq, req);
-wait:
- /* Avoid pointless unplugs. */
- blk_stop_queue(rq);
- break;
- }
-
- queued++;
- }
-
- if (queued != 0)
- flush_requests(info);
-}
-
static int blk_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *qd)
{
@@ -697,27 +648,21 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
struct request_queue *rq;
struct blkfront_info *info = gd->private_data;

- if (info->feature_multiqueue) {
- memset(&info->tag_set, 0, sizeof(info->tag_set));
- info->tag_set.ops = &blkfront_mq_ops;
- info->tag_set.nr_hw_queues = 1;
- info->tag_set.queue_depth = BLK_RING_SIZE;
- info->tag_set.numa_node = NUMA_NO_NODE;
- info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
- info->tag_set.cmd_size = 0;
- info->tag_set.driver_data = info;
-
- if (blk_mq_alloc_tag_set(&info->tag_set))
- return -1;
- rq = blk_mq_init_queue(&info->tag_set);
- if (IS_ERR(rq)) {
- blk_mq_free_tag_set(&info->tag_set);
- return -1;
- }
- } else {
- rq = blk_init_queue(do_blkif_request, &info->io_lock);
- if (rq == NULL)
- return -1;
+ memset(&info->tag_set, 0, sizeof(info->tag_set));
+ info->tag_set.ops = &blkfront_mq_ops;
+ info->tag_set.nr_hw_queues = 1;
+ info->tag_set.queue_depth = BLK_RING_SIZE;
+ info->tag_set.numa_node = NUMA_NO_NODE;
+ info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ info->tag_set.cmd_size = 0;
+ info->tag_set.driver_data = info;
+
+ if (blk_mq_alloc_tag_set(&info->tag_set))
+ return -1;
+ rq = blk_mq_init_queue(&info->tag_set);
+ if (IS_ERR(rq)) {
+ blk_mq_free_tag_set(&info->tag_set);
+ return -1;
}

queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
@@ -954,10 +899,7 @@ static void xlvbd_release_gendisk(struct blkfront_info *info)
spin_lock_irqsave(&info->io_lock, flags);

/* No more blkif_request(). */
- if (info->feature_multiqueue)
- blk_mq_stop_hw_queues(info->rq);
- else
- blk_stop_queue(info->rq);
+ blk_mq_stop_hw_queues(info->rq);

/* No more gnttab callback work. */
gnttab_cancel_free_callback(&info->callback);
@@ -980,18 +922,11 @@ static void xlvbd_release_gendisk(struct blkfront_info *info)
info->gd = NULL;
}

+/* Called with info->io_lock holded */
static void kick_pending_request_queues(struct blkfront_info *info)
{
- if (!RING_FULL(&info->ring)) {
- if (info->feature_multiqueue) {
- blk_mq_start_stopped_hw_queues(info->rq, true);
- } else {
- /* Re-enable calldowns. */
- blk_start_queue(info->rq);
- /* Kick things off immediately. */
- do_blkif_request(info->rq);
- }
- }
+ if (!RING_FULL(&info->ring))
+ blk_mq_start_stopped_hw_queues(info->rq, true);
}

static void blkif_restart_queue(struct work_struct *work)
@@ -1015,12 +950,8 @@ static void blkif_free(struct blkfront_info *info, int suspend)
info->connected = suspend ?
BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
/* No more blkif_request(). */
- if (info->rq) {
- if (info->feature_multiqueue)
- blk_mq_stop_hw_queues(info->rq);
- else
- blk_stop_queue(info->rq);
- }
+ if (info->rq)
+ blk_mq_stop_hw_queues(info->rq);

/* Remove all persistent grants */
if (!list_empty(&info->grants)) {
@@ -1204,7 +1135,6 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
RING_IDX i, rp;
unsigned long flags;
struct blkfront_info *info = (struct blkfront_info *)dev_id;
- int error;

spin_lock_irqsave(&info->io_lock, flags);

@@ -1245,40 +1175,37 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
continue;
}

- error = req->errors = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
+ req->errors = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
switch (bret->operation) {
case BLKIF_OP_DISCARD:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
struct request_queue *rq = info->rq;
printk(KERN_WARNING "blkfront: %s: %s op failed\n",
info->gd->disk_name, op_name(bret->operation));
- error = req->errors = -EOPNOTSUPP;
+ req->errors = -EOPNOTSUPP;
info->feature_discard = 0;
info->feature_secdiscard = 0;
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
}
- if (info->feature_multiqueue)
- blk_mq_complete_request(req);
- else
- __blk_end_request_all(req, error);
+ blk_mq_complete_request(req);
break;
case BLKIF_OP_FLUSH_DISKCACHE:
case BLKIF_OP_WRITE_BARRIER:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
printk(KERN_WARNING "blkfront: %s: %s op failed\n",
info->gd->disk_name, op_name(bret->operation));
- error = req->errors = -EOPNOTSUPP;
+ req->errors = -EOPNOTSUPP;
}
if (unlikely(bret->status == BLKIF_RSP_ERROR &&
info->shadow[id].req.u.rw.nr_segments == 0)) {
printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
info->gd->disk_name, op_name(bret->operation));
- error = req->errors = -EOPNOTSUPP;
+ req->errors = -EOPNOTSUPP;
}
- if (unlikely(error)) {
- if (error == -EOPNOTSUPP)
- error = req->errors = 0;
+ if (unlikely(req->errors)) {
+ if (req->errors == -EOPNOTSUPP)
+ req->errors = 0;
info->feature_flush = 0;
xlvbd_flush(info);
}
@@ -1289,10 +1216,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
"request: %x\n", bret->status);

- if (info->feature_multiqueue)
- blk_mq_complete_request(req);
- else
- __blk_end_request_all(req, error);
+ blk_mq_complete_request(req);
break;
default:
BUG();
@@ -1592,28 +1516,6 @@ static int blkif_recover(struct blkfront_info *info)

kfree(copy);

- /*
- * Empty the queue, this is important because we might have
- * requests in the queue with more segments than what we
- * can handle now.
- */
- spin_lock_irq(&info->io_lock);
- while ((req = blk_fetch_request(info->rq)) != NULL) {
- if (req->cmd_flags &
- (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
- list_add(&req->queuelist, &requests);
- continue;
- }
- merge_bio.head = req->bio;
- merge_bio.tail = req->biotail;
- bio_list_merge(&bio_list, &merge_bio);
- req->bio = NULL;
- if (req->cmd_flags & (REQ_FLUSH | REQ_FUA))
- pr_alert("diskcache flush request found!\n");
- __blk_put_request(info->rq, req);
- }
- spin_unlock_irq(&info->io_lock);
-
xenbus_switch_state(info->xbdev, XenbusStateConnected);

spin_lock_irq(&info->io_lock);
@@ -1628,13 +1530,9 @@ static int blkif_recover(struct blkfront_info *info)
/* Requeue pending requests (flush or discard) */
list_del_init(&req->queuelist);
BUG_ON(req->nr_phys_segments > segs);
- if (info->feature_multiqueue)
- blk_mq_requeue_request(req);
- else
- blk_requeue_request(info->rq, req);
+ blk_mq_requeue_request(req);
}
- if (info->feature_multiqueue)
- blk_mq_kick_requeue_list(info->rq);
+ blk_mq_kick_requeue_list(info->rq);
spin_unlock_irq(&info->io_lock);

while ((bio = bio_list_pop(&bio_list)) != NULL) {
@@ -1954,7 +1852,6 @@ static void blkfront_connect(struct blkfront_info *info)
return;
}

- info->feature_multiqueue = 1;
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
physical_sector_size);
if (err) {
--
1.8.3.1


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