Re: [PATCH 05/16] virtio-blk: use virtqueue_add_sgs on req path
On 02/19/2013 03:56 PM, Rusty Russell wrote: > From: Paolo Bonzini > > (This is a respin of Paolo Bonzini's patch, but it calls > virtqueue_add_sgs() instead of his multi-part API). > > This is similar to the previous patch, but a bit more radical > because the bio and req paths now share the buffer construction > code. Because the req path doesn't use vbr->sg, however, we > need to add a couple of arguments to __virtblk_add_req. > > We also need to teach __virtblk_add_req how to build SCSI command > requests. > > Signed-off-by: Paolo Bonzini > Signed-off-by: Rusty Russell Reviewed-by: Asias He > --- > drivers/block/virtio_blk.c | 69 > +--- > 1 file changed, 33 insertions(+), 36 deletions(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index e27bc6c..523a70f 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -102,19 +102,40 @@ 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 virtblk_req *vbr, > + struct scatterlist *data_sg, > + unsigned data_nents) > { > - struct scatterlist hdr, tailer, *sgs[3]; > + struct scatterlist hdr, tailer, cmd, sense, inhdr, *sgs[6]; > unsigned int num_out = 0, num_in = 0; > + int type = vbr->out_hdr.type & ~VIRTIO_BLK_T_OUT; > > sg_init_one(, >out_hdr, sizeof(vbr->out_hdr)); > sgs[num_out++] = > > - if (vbr->nents) { > + /* > + * If this is a packet command we need a couple of additional headers. > + * Behind the normal outhdr we put a segment with the scsi command > + * block, and before the normal inhdr we put the sense data and the > + * inhdr with additional status information. > + */ > + if (type == VIRTIO_BLK_T_SCSI_CMD) { > + sg_init_one(, vbr->req->cmd, vbr->req->cmd_len); > + sgs[num_out++] = > + } > + > + if (data_nents) { > if (vbr->out_hdr.type & VIRTIO_BLK_T_OUT) > - sgs[num_out++] = vbr->sg; > + sgs[num_out++] = data_sg; > else > - sgs[num_out + num_in++] = vbr->sg; > + sgs[num_out + num_in++] = data_sg; > + } > + > + if (type == VIRTIO_BLK_T_SCSI_CMD) { > + sg_init_one(, vbr->req->sense, SCSI_SENSE_BUFFERSIZE); > + sgs[num_out + num_in++] = > + sg_init_one(, >in_hdr, sizeof(vbr->in_hdr)); > + sgs[num_out + num_in++] = > } > > sg_init_one(, >status, sizeof(vbr->status)); > @@ -130,7 +151,8 @@ static void virtblk_add_req(struct virtblk_req *vbr) > int ret; > > spin_lock_irq(vblk->disk->queue->queue_lock); > - while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr)) < 0)) { > + while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr, vbr->sg, > + vbr->nents)) < 0)) { > prepare_to_wait_exclusive(>queue_wait, , > TASK_UNINTERRUPTIBLE); > > @@ -283,7 +305,7 @@ static void virtblk_done(struct virtqueue *vq) > static bool do_req(struct request_queue *q, struct virtio_blk *vblk, > struct request *req) > { > - unsigned long num, out = 0, in = 0; > + unsigned int num; > struct virtblk_req *vbr; > > vbr = virtblk_alloc_req(vblk, GFP_ATOMIC); > @@ -320,40 +342,15 @@ static bool do_req(struct request_queue *q, struct > virtio_blk *vblk, > } > } > > - sg_set_buf(>sg[out++], >out_hdr, sizeof(vbr->out_hdr)); > - > - /* > - * If this is a packet command we need a couple of additional headers. > - * Behind the normal outhdr we put a segment with the scsi command > - * block, and before the normal inhdr we put the sense data and the > - * inhdr with additional status information before the normal inhdr. > - */ > - if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) > - sg_set_buf(>sg[out++], vbr->req->cmd, vbr->req->cmd_len); > - > - num = blk_rq_map_sg(q, vbr->req, vblk->sg + out); > - > - if (vbr->req->cmd_type == REQ_TYPE_BLOCK_PC) { > - sg_set_buf(>sg[num + out + in++], vbr->req->sense, > SCSI_SENSE_BUFFERSIZE); > - sg_set_buf(>sg[num + out + in++], >in_hdr, > -sizeof(vbr->in_hdr)); > - } > - > - sg_set_buf(>sg[num + out + in++], >status, > -sizeof(vbr->status)); > - > + num = blk_rq_map_sg(q, vbr->req, vblk->sg); > if (num) { > - if (rq_data_dir(vbr->req) == WRITE) { > + if (rq_data_dir(vbr->req) == WRITE) > vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; > - out += num; > -
Re: [PATCH 05/16] virtio-blk: use virtqueue_add_sgs on req path
On 02/19/2013 03:56 PM, Rusty Russell wrote: From: Paolo Bonzini pbonz...@redhat.com (This is a respin of Paolo Bonzini's patch, but it calls virtqueue_add_sgs() instead of his multi-part API). This is similar to the previous patch, but a bit more radical because the bio and req paths now share the buffer construction code. Because the req path doesn't use vbr-sg, however, we need to add a couple of arguments to __virtblk_add_req. We also need to teach __virtblk_add_req how to build SCSI command requests. Signed-off-by: Paolo Bonzini pbonz...@redhat.com Signed-off-by: Rusty Russell ru...@rustcorp.com.au Reviewed-by: Asias He as...@redhat.com --- drivers/block/virtio_blk.c | 69 +--- 1 file changed, 33 insertions(+), 36 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index e27bc6c..523a70f 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -102,19 +102,40 @@ 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 virtblk_req *vbr, + struct scatterlist *data_sg, + unsigned data_nents) { - struct scatterlist hdr, tailer, *sgs[3]; + struct scatterlist hdr, tailer, cmd, sense, inhdr, *sgs[6]; unsigned int num_out = 0, num_in = 0; + int type = vbr-out_hdr.type ~VIRTIO_BLK_T_OUT; sg_init_one(hdr, vbr-out_hdr, sizeof(vbr-out_hdr)); sgs[num_out++] = hdr; - if (vbr-nents) { + /* + * If this is a packet command we need a couple of additional headers. + * Behind the normal outhdr we put a segment with the scsi command + * block, and before the normal inhdr we put the sense data and the + * inhdr with additional status information. + */ + if (type == VIRTIO_BLK_T_SCSI_CMD) { + sg_init_one(cmd, vbr-req-cmd, vbr-req-cmd_len); + sgs[num_out++] = cmd; + } + + if (data_nents) { if (vbr-out_hdr.type VIRTIO_BLK_T_OUT) - sgs[num_out++] = vbr-sg; + sgs[num_out++] = data_sg; else - sgs[num_out + num_in++] = vbr-sg; + sgs[num_out + num_in++] = data_sg; + } + + if (type == VIRTIO_BLK_T_SCSI_CMD) { + sg_init_one(sense, vbr-req-sense, SCSI_SENSE_BUFFERSIZE); + sgs[num_out + num_in++] = sense; + sg_init_one(inhdr, vbr-in_hdr, sizeof(vbr-in_hdr)); + sgs[num_out + num_in++] = inhdr; } sg_init_one(tailer, vbr-status, sizeof(vbr-status)); @@ -130,7 +151,8 @@ static void virtblk_add_req(struct virtblk_req *vbr) int ret; spin_lock_irq(vblk-disk-queue-queue_lock); - while (unlikely((ret = __virtblk_add_req(vblk-vq, vbr)) 0)) { + while (unlikely((ret = __virtblk_add_req(vblk-vq, vbr, vbr-sg, + vbr-nents)) 0)) { prepare_to_wait_exclusive(vblk-queue_wait, wait, TASK_UNINTERRUPTIBLE); @@ -283,7 +305,7 @@ static void virtblk_done(struct virtqueue *vq) static bool do_req(struct request_queue *q, struct virtio_blk *vblk, struct request *req) { - unsigned long num, out = 0, in = 0; + unsigned int num; struct virtblk_req *vbr; vbr = virtblk_alloc_req(vblk, GFP_ATOMIC); @@ -320,40 +342,15 @@ static bool do_req(struct request_queue *q, struct virtio_blk *vblk, } } - sg_set_buf(vblk-sg[out++], vbr-out_hdr, sizeof(vbr-out_hdr)); - - /* - * If this is a packet command we need a couple of additional headers. - * Behind the normal outhdr we put a segment with the scsi command - * block, and before the normal inhdr we put the sense data and the - * inhdr with additional status information before the normal inhdr. - */ - if (vbr-req-cmd_type == REQ_TYPE_BLOCK_PC) - sg_set_buf(vblk-sg[out++], vbr-req-cmd, vbr-req-cmd_len); - - num = blk_rq_map_sg(q, vbr-req, vblk-sg + out); - - if (vbr-req-cmd_type == REQ_TYPE_BLOCK_PC) { - sg_set_buf(vblk-sg[num + out + in++], vbr-req-sense, SCSI_SENSE_BUFFERSIZE); - sg_set_buf(vblk-sg[num + out + in++], vbr-in_hdr, -sizeof(vbr-in_hdr)); - } - - sg_set_buf(vblk-sg[num + out + in++], vbr-status, -sizeof(vbr-status)); - + num = blk_rq_map_sg(q, vbr-req, vblk-sg); if (num) { - if (rq_data_dir(vbr-req) == WRITE) { + if (rq_data_dir(vbr-req) == WRITE) vbr-out_hdr.type |= VIRTIO_BLK_T_OUT; - out += num; - }