On 02/19/2013 03:56 PM, Rusty Russell wrote:
> It's simply a flag as to whether we have data now, so make it an
> explicit function parameter rather than a member of struct
> virtblk_req.
>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Reviewed-by: Asias He <asias@xxxxxxxxxx>
> ---
> drivers/block/virtio_blk.c | 22 +++++++++++-----------
> 1 file changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 523a70f..6369cb9 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -62,7 +62,6 @@ struct virtblk_req
> struct virtio_blk *vblk;
> int flags;
> u8 status;
> - int nents;
> struct scatterlist sg[];
> };
>
> @@ -104,7 +103,7 @@ static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk,
> static int __virtblk_add_req(struct virtqueue *vq,
> struct virtblk_req *vbr,
> struct scatterlist *data_sg,
> - unsigned data_nents)
> + bool have_data)
> {
> struct scatterlist hdr, tailer, cmd, sense, inhdr, *sgs[6];
> unsigned int num_out = 0, num_in = 0;
> @@ -124,7 +123,7 @@ static int __virtblk_add_req(struct virtqueue *vq,
> sgs[num_out++] = &cmd;
> }
>
> - if (data_nents) {
> + if (have_data) {
> if (vbr->out_hdr.type & VIRTIO_BLK_T_OUT)
> sgs[num_out++] = data_sg;
> else
> @@ -144,7 +143,7 @@ static int __virtblk_add_req(struct virtqueue *vq,
> return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
> }
>
> -static void virtblk_add_req(struct virtblk_req *vbr)
> +static void virtblk_add_req(struct virtblk_req *vbr, bool have_data)
> {
> struct virtio_blk *vblk = vbr->vblk;
> DEFINE_WAIT(wait);
> @@ -152,7 +151,7 @@ static void virtblk_add_req(struct virtblk_req *vbr)
>
> spin_lock_irq(vblk->disk->queue->queue_lock);
> while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr, vbr->sg,
> - vbr->nents)) < 0)) {
> + have_data)) < 0)) {
> prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
> TASK_UNINTERRUPTIBLE);
>
> @@ -173,30 +172,31 @@ static void virtblk_bio_send_flush(struct virtblk_req *vbr)
> vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
> vbr->out_hdr.sector = 0;
> vbr->out_hdr.ioprio = 0;
> - vbr->nents = 0;
>
> - virtblk_add_req(vbr);
> + virtblk_add_req(vbr, false);
> }
>
> static void virtblk_bio_send_data(struct virtblk_req *vbr)
> {
> struct virtio_blk *vblk = vbr->vblk;
> struct bio *bio = vbr->bio;
> + bool have_data;
>
> vbr->flags &= ~VBLK_IS_FLUSH;
> vbr->out_hdr.type = 0;
> vbr->out_hdr.sector = bio->bi_sector;
> vbr->out_hdr.ioprio = bio_prio(bio);
>
> - vbr->nents = blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg);
> - if (vbr->nents) {
> + if (blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg)) {
> + have_data = true;
> if (bio->bi_rw & REQ_WRITE)
> vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
> else
> vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
> - }
> + } else
> + have_data = false;
>
> - virtblk_add_req(vbr);
> + virtblk_add_req(vbr, have_data);
> }
>
> static void virtblk_bio_send_data_work(struct work_struct *work)
>
--
Asias
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