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sunvdc: convert to blk-mq
authorJens Axboe <axboe@kernel.dk>
Mon, 15 Oct 2018 14:54:23 +0000 (08:54 -0600)
committerJens Axboe <axboe@kernel.dk>
Wed, 7 Nov 2018 20:42:31 +0000 (13:42 -0700)
Convert from the old request_fn style driver to blk-mq.

Cc: David Miller <davem@davemloft.net>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
drivers/block/sunvdc.c

index b54fa67..95cb4ea 100644 (file)
@@ -6,7 +6,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
-#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
 #include <linux/hdreg.h>
 #include <linux/genhd.h>
 #include <linux/cdrom.h>
@@ -66,9 +66,10 @@ struct vdc_port {
 
        u64                     max_xfer_size;
        u32                     vdisk_block_size;
+       u32                     drain;
 
        u64                     ldc_timeout;
-       struct timer_list       ldc_reset_timer;
+       struct delayed_work     ldc_reset_timer_work;
        struct work_struct      ldc_reset_work;
 
        /* The server fills these in for us in the disk attribute
@@ -80,12 +81,14 @@ struct vdc_port {
        u8                      vdisk_mtype;
        u32                     vdisk_phys_blksz;
 
+       struct blk_mq_tag_set   tag_set;
+
        char                    disk_name[32];
 };
 
 static void vdc_ldc_reset(struct vdc_port *port);
 static void vdc_ldc_reset_work(struct work_struct *work);
-static void vdc_ldc_reset_timer(struct timer_list *t);
+static void vdc_ldc_reset_timer_work(struct work_struct *work);
 
 static inline struct vdc_port *to_vdc_port(struct vio_driver_state *vio)
 {
@@ -175,11 +178,8 @@ static void vdc_blk_queue_start(struct vdc_port *port)
         * handshake completes, so check for initial handshake before we've
         * allocated a disk.
         */
-       if (port->disk && blk_queue_stopped(port->disk->queue) &&
-           vdc_tx_dring_avail(dr) * 100 / VDC_TX_RING_SIZE >= 50) {
-               blk_start_queue(port->disk->queue);
-       }
-
+       if (port->disk && vdc_tx_dring_avail(dr) * 100 / VDC_TX_RING_SIZE >= 50)
+               blk_mq_start_hw_queues(port->disk->queue);
 }
 
 static void vdc_finish(struct vio_driver_state *vio, int err, int waiting_for)
@@ -197,7 +197,7 @@ static void vdc_handshake_complete(struct vio_driver_state *vio)
 {
        struct vdc_port *port = to_vdc_port(vio);
 
-       del_timer(&port->ldc_reset_timer);
+       cancel_delayed_work(&port->ldc_reset_timer_work);
        vdc_finish(vio, 0, WAITING_FOR_LINK_UP);
        vdc_blk_queue_start(port);
 }
@@ -320,7 +320,7 @@ static void vdc_end_one(struct vdc_port *port, struct vio_dring_state *dr,
 
        rqe->req = NULL;
 
-       __blk_end_request(req, (desc->status ? BLK_STS_IOERR : 0), desc->size);
+       blk_mq_end_request(req, desc->status ? BLK_STS_IOERR : 0);
 
        vdc_blk_queue_start(port);
 }
@@ -525,29 +525,40 @@ static int __send_request(struct request *req)
        return err;
 }
 
-static void do_vdc_request(struct request_queue *rq)
+static blk_status_t vdc_queue_rq(struct blk_mq_hw_ctx *hctx,
+                                const struct blk_mq_queue_data *bd)
 {
-       struct request *req;
+       struct vdc_port *port = hctx->queue->queuedata;
+       struct vio_dring_state *dr;
+       unsigned long flags;
 
-       while ((req = blk_peek_request(rq)) != NULL) {
-               struct vdc_port *port;
-               struct vio_dring_state *dr;
+       dr = &port->vio.drings[VIO_DRIVER_TX_RING];
 
-               port = req->rq_disk->private_data;
-               dr = &port->vio.drings[VIO_DRIVER_TX_RING];
-               if (unlikely(vdc_tx_dring_avail(dr) < 1))
-                       goto wait;
+       blk_mq_start_request(bd->rq);
 
-               blk_start_request(req);
+       spin_lock_irqsave(&port->vio.lock, flags);
 
-               if (__send_request(req) < 0) {
-                       blk_requeue_request(rq, req);
-wait:
-                       /* Avoid pointless unplugs. */
-                       blk_stop_queue(rq);
-                       break;
-               }
+       /*
+        * Doing drain, just end the request in error
+        */
+       if (unlikely(port->drain)) {
+               spin_unlock_irqrestore(&port->vio.lock, flags);
+               return BLK_STS_IOERR;
        }
+
+       if (unlikely(vdc_tx_dring_avail(dr) < 1)) {
+               spin_unlock_irqrestore(&port->vio.lock, flags);
+               blk_mq_stop_hw_queue(hctx);
+               return BLK_STS_DEV_RESOURCE;
+       }
+
+       if (__send_request(bd->rq) < 0) {
+               spin_unlock_irqrestore(&port->vio.lock, flags);
+               return BLK_STS_IOERR;
+       }
+
+       spin_unlock_irqrestore(&port->vio.lock, flags);
+       return BLK_STS_OK;
 }
 
 static int generic_request(struct vdc_port *port, u8 op, void *buf, int len)
@@ -759,6 +770,32 @@ static void vdc_port_down(struct vdc_port *port)
        vio_ldc_free(&port->vio);
 }
 
+static const struct blk_mq_ops vdc_mq_ops = {
+       .queue_rq       = vdc_queue_rq,
+};
+
+static void cleanup_queue(struct request_queue *q)
+{
+       struct vdc_port *port = q->queuedata;
+
+       blk_cleanup_queue(q);
+       blk_mq_free_tag_set(&port->tag_set);
+}
+
+static struct request_queue *init_queue(struct vdc_port *port)
+{
+       struct request_queue *q;
+       int ret;
+
+       q = blk_mq_init_sq_queue(&port->tag_set, &vdc_mq_ops, VDC_TX_RING_SIZE,
+                                       BLK_MQ_F_SHOULD_MERGE);
+       if (IS_ERR(q))
+               return q;
+
+       q->queuedata = port;
+       return q;
+}
+
 static int probe_disk(struct vdc_port *port)
 {
        struct request_queue *q;
@@ -796,17 +833,17 @@ static int probe_disk(struct vdc_port *port)
                                    (u64)geom.num_sec);
        }
 
-       q = blk_init_queue(do_vdc_request, &port->vio.lock);
-       if (!q) {
+       q = init_queue(port);
+       if (IS_ERR(q)) {
                printk(KERN_ERR PFX "%s: Could not allocate queue.\n",
                       port->vio.name);
-               return -ENOMEM;
+               return PTR_ERR(q);
        }
        g = alloc_disk(1 << PARTITION_SHIFT);
        if (!g) {
                printk(KERN_ERR PFX "%s: Could not allocate gendisk.\n",
                       port->vio.name);
-               blk_cleanup_queue(q);
+               cleanup_queue(q);
                return -ENOMEM;
        }
 
@@ -981,7 +1018,7 @@ static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id)
         */
        ldc_timeout = mdesc_get_property(hp, vdev->mp, "vdc-timeout", NULL);
        port->ldc_timeout = ldc_timeout ? *ldc_timeout : 0;
-       timer_setup(&port->ldc_reset_timer, vdc_ldc_reset_timer, 0);
+       INIT_DELAYED_WORK(&port->ldc_reset_timer_work, vdc_ldc_reset_timer_work);
        INIT_WORK(&port->ldc_reset_work, vdc_ldc_reset_work);
 
        err = vio_driver_init(&port->vio, vdev, VDEV_DISK,
@@ -1034,18 +1071,14 @@ static int vdc_port_remove(struct vio_dev *vdev)
        struct vdc_port *port = dev_get_drvdata(&vdev->dev);
 
        if (port) {
-               unsigned long flags;
-
-               spin_lock_irqsave(&port->vio.lock, flags);
-               blk_stop_queue(port->disk->queue);
-               spin_unlock_irqrestore(&port->vio.lock, flags);
+               blk_mq_stop_hw_queues(port->disk->queue);
 
                flush_work(&port->ldc_reset_work);
-               del_timer_sync(&port->ldc_reset_timer);
+               cancel_delayed_work_sync(&port->ldc_reset_timer_work);
                del_timer_sync(&port->vio.timer);
 
                del_gendisk(port->disk);
-               blk_cleanup_queue(port->disk->queue);
+               cleanup_queue(port->disk->queue);
                put_disk(port->disk);
                port->disk = NULL;
 
@@ -1080,32 +1113,46 @@ static void vdc_requeue_inflight(struct vdc_port *port)
                }
 
                rqe->req = NULL;
-               blk_requeue_request(port->disk->queue, req);
+               blk_mq_requeue_request(req, false);
        }
 }
 
 static void vdc_queue_drain(struct vdc_port *port)
 {
-       struct request *req;
+       struct request_queue *q = port->disk->queue;
 
-       while ((req = blk_fetch_request(port->disk->queue)) != NULL)
-               __blk_end_request_all(req, BLK_STS_IOERR);
+       /*
+        * Mark the queue as draining, then freeze/quiesce to ensure
+        * that all existing requests are seen in ->queue_rq() and killed
+        */
+       port->drain = 1;
+       spin_unlock_irq(&port->vio.lock);
+
+       blk_mq_freeze_queue(q);
+       blk_mq_quiesce_queue(q);
+
+       spin_lock_irq(&port->vio.lock);
+       port->drain = 0;
+       blk_mq_unquiesce_queue(q);
+       blk_mq_unfreeze_queue(q);
 }
 
-static void vdc_ldc_reset_timer(struct timer_list *t)
+static void vdc_ldc_reset_timer_work(struct work_struct *work)
 {
-       struct vdc_port *port = from_timer(port, t, ldc_reset_timer);
-       struct vio_driver_state *vio = &port->vio;
-       unsigned long flags;
+       struct vdc_port *port;
+       struct vio_driver_state *vio;
 
-       spin_lock_irqsave(&vio->lock, flags);
+       port = container_of(work, struct vdc_port, ldc_reset_timer_work.work);
+       vio = &port->vio;
+
+       spin_lock_irq(&vio->lock);
        if (!(port->vio.hs_state & VIO_HS_COMPLETE)) {
                pr_warn(PFX "%s ldc down %llu seconds, draining queue\n",
                        port->disk_name, port->ldc_timeout);
                vdc_queue_drain(port);
                vdc_blk_queue_start(port);
        }
-       spin_unlock_irqrestore(&vio->lock, flags);
+       spin_unlock_irq(&vio->lock);
 }
 
 static void vdc_ldc_reset_work(struct work_struct *work)
@@ -1129,7 +1176,7 @@ static void vdc_ldc_reset(struct vdc_port *port)
        assert_spin_locked(&port->vio.lock);
 
        pr_warn(PFX "%s ldc link reset\n", port->disk_name);
-       blk_stop_queue(port->disk->queue);
+       blk_mq_stop_hw_queues(port->disk->queue);
        vdc_requeue_inflight(port);
        vdc_port_down(port);
 
@@ -1146,7 +1193,7 @@ static void vdc_ldc_reset(struct vdc_port *port)
        }
 
        if (port->ldc_timeout)
-               mod_timer(&port->ldc_reset_timer,
+               mod_delayed_work(system_wq, &port->ldc_reset_timer_work,
                          round_jiffies(jiffies + HZ * port->ldc_timeout));
        mod_timer(&port->vio.timer, round_jiffies(jiffies + HZ));
        return;