From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 15 Oct 2018 18:38:12 +0800 From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, David Miller Subject: Re: [PATCH 01/17] sunvdc: convert to blk-mq Message-ID: <20181015103728.GC31722@ming.t460p> References: <20181011165909.32615-1-axboe@kernel.dk> <20181011165909.32615-2-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20181011165909.32615-2-axboe@kernel.dk> List-ID: On Thu, Oct 11, 2018 at 10:58:53AM -0600, Jens Axboe wrote: > Convert from the old request_fn style driver to blk-mq. > > Cc: David Miller > Signed-off-by: Jens Axboe > --- > drivers/block/sunvdc.c | 161 ++++++++++++++++++++++++++++------------- > 1 file changed, 110 insertions(+), 51 deletions(-) > > diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c > index f68e9baffad7..bf51a2307ce1 100644 > --- a/drivers/block/sunvdc.c > +++ b/drivers/block/sunvdc.c > @@ -6,7 +6,7 @@ > #include > #include > #include > -#include > +#include > #include > #include > #include > @@ -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); blk_mq_end_request() may trigger BUG in case of partial completion, however looks it is fine for __blk_end_request(). > > 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 +770,44 @@ 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_mq_free_tag_set(&port->tag_set); > + blk_cleanup_queue(q); blk_mq_free_tag_set() need to be put after blk_cleanup_queue(). > +} > + > +static struct request_queue *init_queue(struct vdc_port *port) > +{ > + struct blk_mq_tag_set *set = &port->tag_set; > + struct request_queue *q; > + int ret; > + > + set->ops = &vdc_mq_ops; > + set->nr_hw_queues = 1; > + set->queue_depth = VDC_TX_RING_SIZE; > + set->numa_node = NUMA_NO_NODE; > + set->flags = BLK_MQ_F_SHOULD_MERGE; > + > + ret = blk_mq_alloc_tag_set(set); > + if (ret) > + return ERR_PTR(ret); > + > + q = blk_mq_init_queue(set); > + if (IS_ERR(q)) { > + blk_mq_free_tag_set(set); > + return q; > + } Most of conversions have the above pattern, maybe it is easier to introduce the following block API: struct reuqest_queue *blk_mq_alloc_and_init_sq(set, ops, queue_depth) -- Ming