From 8f39db9d3709afe944710f124111ec87467d25c7 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 20 Mar 2013 15:44:27 +1030 Subject: virtio-blk: use virtqueue_add_sgs on bio path (This is a respin of Paolo Bonzini's patch, but it calls virtqueue_add_sgs() instead of his multi-part API). Move the creation of the request header and response footer to __virtblk_add_req. vbr->sg only contains the data scatterlist, the header/footer are added separately using virtqueue_add_sgs(). With this change, virtio-blk (with use_bio) is not relying anymore on the virtio functions ignoring the end markers in a scatterlist. The next patch will do the same for the other path. Signed-off-by: Paolo Bonzini Signed-off-by: Rusty Russell Reviewed-by: Asias He --- drivers/block/virtio_blk.c | 58 +++++++++++++++++++++++----------------------- 1 file changed, 29 insertions(+), 29 deletions(-) (limited to 'drivers/block/virtio_blk.c') diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index b271650032fa..cfbe39d35277 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -62,6 +62,7 @@ struct virtblk_req struct virtio_blk *vblk; int flags; u8 status; + int nents; struct scatterlist sg[]; }; @@ -100,24 +101,36 @@ static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk, return vbr; } -static inline int __virtblk_add_req(struct virtqueue *vq, - struct virtblk_req *vbr, - unsigned long out, - unsigned long in) +static int __virtblk_add_req(struct virtqueue *vq, + struct virtblk_req *vbr) { - return virtqueue_add_buf(vq, vbr->sg, out, in, vbr, GFP_ATOMIC); + struct scatterlist hdr, status, *sgs[3]; + unsigned int num_out = 0, num_in = 0; + + sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); + sgs[num_out++] = &hdr; + + if (vbr->nents) { + if (vbr->out_hdr.type & VIRTIO_BLK_T_OUT) + sgs[num_out++] = vbr->sg; + else + sgs[num_out + num_in++] = vbr->sg; + } + + sg_init_one(&status, &vbr->status, sizeof(vbr->status)); + sgs[num_out + num_in++] = &status; + + return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); } -static void virtblk_add_req(struct virtblk_req *vbr, - unsigned int out, unsigned int in) +static void virtblk_add_req(struct virtblk_req *vbr) { struct virtio_blk *vblk = vbr->vblk; DEFINE_WAIT(wait); int ret; spin_lock_irq(vblk->disk->queue->queue_lock); - while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr, - out, in)) < 0)) { + while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr)) < 0)) { prepare_to_wait_exclusive(&vblk->queue_wait, &wait, TASK_UNINTERRUPTIBLE); @@ -134,22 +147,18 @@ static void virtblk_add_req(struct virtblk_req *vbr, static void virtblk_bio_send_flush(struct virtblk_req *vbr) { - unsigned int out = 0, in = 0; - vbr->flags |= VBLK_IS_FLUSH; vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; vbr->out_hdr.sector = 0; vbr->out_hdr.ioprio = 0; - sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); - sg_set_buf(&vbr->sg[out + in++], &vbr->status, sizeof(vbr->status)); + vbr->nents = 0; - virtblk_add_req(vbr, out, in); + virtblk_add_req(vbr); } static void virtblk_bio_send_data(struct virtblk_req *vbr) { struct virtio_blk *vblk = vbr->vblk; - unsigned int num, out = 0, in = 0; struct bio *bio = vbr->bio; vbr->flags &= ~VBLK_IS_FLUSH; @@ -157,24 +166,15 @@ static void virtblk_bio_send_data(struct virtblk_req *vbr) vbr->out_hdr.sector = bio->bi_sector; vbr->out_hdr.ioprio = bio_prio(bio); - sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); - - num = blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg + out); - - sg_set_buf(&vbr->sg[num + out + in++], &vbr->status, - sizeof(vbr->status)); - - if (num) { - if (bio->bi_rw & REQ_WRITE) { + vbr->nents = blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg); + if (vbr->nents) { + if (bio->bi_rw & REQ_WRITE) vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; - out += num; - } else { + else vbr->out_hdr.type |= VIRTIO_BLK_T_IN; - in += num; - } } - virtblk_add_req(vbr, out, in); + virtblk_add_req(vbr); } static void virtblk_bio_send_data_work(struct work_struct *work) -- cgit v1.2.3