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virtio-blk: Add REQ_FLUSH and REQ_FUA support to bio path
We need to support both REQ_FLUSH and REQ_FUA for bio based path since it does not get the sequencing of REQ_FUA into REQ_FLUSH that request based drivers can request. REQ_FLUSH is emulated by: A) If the bio has no data to write: 1. Send VIRTIO_BLK_T_FLUSH to device, 2. In the flush I/O completion handler, finish the bio B) If the bio has data to write: 1. Send VIRTIO_BLK_T_FLUSH to device 2. In the flush I/O completion handler, send the actual write data to device 3. In the write I/O completion handler, finish the bio REQ_FUA is emulated by: 1. Send the actual write data to device 2. In the write I/O completion handler, send VIRTIO_BLK_T_FLUSH to device 3. In the flush I/O completion handler, finish the bio Changes in v7: - Using vbr->flags to trace request type - Dropped unnecessary struct virtio_blk *vblk parameter - Reuse struct virtblk_req in bio done function Cahnges in v6: - Reworked REQ_FLUSH and REQ_FUA emulatation order Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Cc: Tejun Heo <tj@kernel.org> Cc: Shaohua Li <shli@kernel.org> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Asias He
Rusty Russell
parent
a98755c559
commit
c85a1f91b3
@ -58,10 +58,20 @@ struct virtblk_req
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struct bio *bio;
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struct virtio_blk_outhdr out_hdr;
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struct virtio_scsi_inhdr in_hdr;
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struct work_struct work;
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struct virtio_blk *vblk;
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int flags;
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u8 status;
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struct scatterlist sg[];
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};
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enum {
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VBLK_IS_FLUSH = 1,
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VBLK_REQ_FLUSH = 2,
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VBLK_REQ_DATA = 4,
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VBLK_REQ_FUA = 8,
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};
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static inline int virtblk_result(struct virtblk_req *vbr)
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{
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switch (vbr->status) {
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@ -74,9 +84,133 @@ static inline int virtblk_result(struct virtblk_req *vbr)
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}
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}
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static inline void virtblk_request_done(struct virtio_blk *vblk,
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struct virtblk_req *vbr)
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static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk,
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gfp_t gfp_mask)
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{
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struct virtblk_req *vbr;
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vbr = mempool_alloc(vblk->pool, gfp_mask);
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if (vbr && use_bio)
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sg_init_table(vbr->sg, vblk->sg_elems);
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vbr->vblk = vblk;
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return vbr;
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}
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static void virtblk_add_buf_wait(struct virtio_blk *vblk,
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struct virtblk_req *vbr,
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unsigned long out,
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unsigned long in)
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{
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DEFINE_WAIT(wait);
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for (;;) {
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prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
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TASK_UNINTERRUPTIBLE);
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spin_lock_irq(vblk->disk->queue->queue_lock);
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if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
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GFP_ATOMIC) < 0) {
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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io_schedule();
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} else {
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virtqueue_kick(vblk->vq);
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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break;
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}
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}
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finish_wait(&vblk->queue_wait, &wait);
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}
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static inline void virtblk_add_req(struct virtblk_req *vbr,
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unsigned int out, unsigned int in)
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{
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struct virtio_blk *vblk = vbr->vblk;
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spin_lock_irq(vblk->disk->queue->queue_lock);
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if (unlikely(virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
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GFP_ATOMIC) < 0)) {
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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virtblk_add_buf_wait(vblk, vbr, out, in);
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return;
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}
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virtqueue_kick(vblk->vq);
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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}
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static int virtblk_bio_send_flush(struct virtblk_req *vbr)
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{
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unsigned int out = 0, in = 0;
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vbr->flags |= VBLK_IS_FLUSH;
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vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
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vbr->out_hdr.sector = 0;
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vbr->out_hdr.ioprio = 0;
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sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
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sg_set_buf(&vbr->sg[out + in++], &vbr->status, sizeof(vbr->status));
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virtblk_add_req(vbr, out, in);
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return 0;
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}
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static int virtblk_bio_send_data(struct virtblk_req *vbr)
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{
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struct virtio_blk *vblk = vbr->vblk;
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unsigned int num, out = 0, in = 0;
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struct bio *bio = vbr->bio;
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vbr->flags &= ~VBLK_IS_FLUSH;
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vbr->out_hdr.type = 0;
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vbr->out_hdr.sector = bio->bi_sector;
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vbr->out_hdr.ioprio = bio_prio(bio);
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sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
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num = blk_bio_map_sg(vblk->disk->queue, bio, vbr->sg + out);
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sg_set_buf(&vbr->sg[num + out + in++], &vbr->status,
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sizeof(vbr->status));
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if (num) {
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if (bio->bi_rw & REQ_WRITE) {
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vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
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out += num;
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} else {
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vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
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in += num;
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}
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}
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virtblk_add_req(vbr, out, in);
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return 0;
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}
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static void virtblk_bio_send_data_work(struct work_struct *work)
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{
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struct virtblk_req *vbr;
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vbr = container_of(work, struct virtblk_req, work);
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virtblk_bio_send_data(vbr);
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}
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static void virtblk_bio_send_flush_work(struct work_struct *work)
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{
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struct virtblk_req *vbr;
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vbr = container_of(work, struct virtblk_req, work);
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virtblk_bio_send_flush(vbr);
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}
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static inline void virtblk_request_done(struct virtblk_req *vbr)
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{
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struct virtio_blk *vblk = vbr->vblk;
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struct request *req = vbr->req;
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int error = virtblk_result(vbr);
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@ -92,17 +226,47 @@ static inline void virtblk_request_done(struct virtio_blk *vblk,
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mempool_free(vbr, vblk->pool);
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}
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static inline void virtblk_bio_done(struct virtio_blk *vblk,
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struct virtblk_req *vbr)
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static inline void virtblk_bio_flush_done(struct virtblk_req *vbr)
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{
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bio_endio(vbr->bio, virtblk_result(vbr));
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mempool_free(vbr, vblk->pool);
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struct virtio_blk *vblk = vbr->vblk;
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if (vbr->flags & VBLK_REQ_DATA) {
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/* Send out the actual write data */
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INIT_WORK(&vbr->work, virtblk_bio_send_data_work);
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queue_work(virtblk_wq, &vbr->work);
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} else {
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bio_endio(vbr->bio, virtblk_result(vbr));
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mempool_free(vbr, vblk->pool);
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}
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}
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static inline void virtblk_bio_data_done(struct virtblk_req *vbr)
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{
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struct virtio_blk *vblk = vbr->vblk;
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if (unlikely(vbr->flags & VBLK_REQ_FUA)) {
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/* Send out a flush before end the bio */
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vbr->flags &= ~VBLK_REQ_DATA;
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INIT_WORK(&vbr->work, virtblk_bio_send_flush_work);
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queue_work(virtblk_wq, &vbr->work);
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} else {
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bio_endio(vbr->bio, virtblk_result(vbr));
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mempool_free(vbr, vblk->pool);
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}
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}
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static inline void virtblk_bio_done(struct virtblk_req *vbr)
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{
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if (unlikely(vbr->flags & VBLK_IS_FLUSH))
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virtblk_bio_flush_done(vbr);
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else
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virtblk_bio_data_done(vbr);
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}
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static void virtblk_done(struct virtqueue *vq)
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{
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struct virtio_blk *vblk = vq->vdev->priv;
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unsigned long bio_done = 0, req_done = 0;
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bool bio_done = false, req_done = false;
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struct virtblk_req *vbr;
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unsigned long flags;
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unsigned int len;
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@ -110,11 +274,11 @@ static void virtblk_done(struct virtqueue *vq)
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spin_lock_irqsave(vblk->disk->queue->queue_lock, flags);
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while ((vbr = virtqueue_get_buf(vblk->vq, &len)) != NULL) {
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if (vbr->bio) {
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virtblk_bio_done(vblk, vbr);
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bio_done++;
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virtblk_bio_done(vbr);
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bio_done = true;
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} else {
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virtblk_request_done(vblk, vbr);
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req_done++;
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virtblk_request_done(vbr);
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req_done = true;
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}
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}
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/* In case queue is stopped waiting for more buffers. */
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@ -126,18 +290,6 @@ static void virtblk_done(struct virtqueue *vq)
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wake_up(&vblk->queue_wait);
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}
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static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk,
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gfp_t gfp_mask)
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{
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struct virtblk_req *vbr;
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vbr = mempool_alloc(vblk->pool, gfp_mask);
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if (vbr && use_bio)
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sg_init_table(vbr->sg, vblk->sg_elems);
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return vbr;
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}
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static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
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struct request *req)
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{
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@ -242,41 +394,12 @@ static void virtblk_request(struct request_queue *q)
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virtqueue_kick(vblk->vq);
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}
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static void virtblk_add_buf_wait(struct virtio_blk *vblk,
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struct virtblk_req *vbr,
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unsigned long out,
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unsigned long in)
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{
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DEFINE_WAIT(wait);
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for (;;) {
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prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
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TASK_UNINTERRUPTIBLE);
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spin_lock_irq(vblk->disk->queue->queue_lock);
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if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
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GFP_ATOMIC) < 0) {
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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io_schedule();
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} else {
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virtqueue_kick(vblk->vq);
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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break;
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}
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}
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finish_wait(&vblk->queue_wait, &wait);
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}
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static void virtblk_make_request(struct request_queue *q, struct bio *bio)
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{
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struct virtio_blk *vblk = q->queuedata;
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unsigned int num, out = 0, in = 0;
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struct virtblk_req *vbr;
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BUG_ON(bio->bi_phys_segments + 2 > vblk->sg_elems);
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BUG_ON(bio->bi_rw & (REQ_FLUSH | REQ_FUA));
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vbr = virtblk_alloc_req(vblk, GFP_NOIO);
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if (!vbr) {
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@ -285,37 +408,18 @@ static void virtblk_make_request(struct request_queue *q, struct bio *bio)
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}
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vbr->bio = bio;
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vbr->req = NULL;
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vbr->out_hdr.type = 0;
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vbr->out_hdr.sector = bio->bi_sector;
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vbr->out_hdr.ioprio = bio_prio(bio);
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vbr->flags = 0;
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if (bio->bi_rw & REQ_FLUSH)
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vbr->flags |= VBLK_REQ_FLUSH;
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if (bio->bi_rw & REQ_FUA)
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vbr->flags |= VBLK_REQ_FUA;
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if (bio->bi_size)
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vbr->flags |= VBLK_REQ_DATA;
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sg_set_buf(&vbr->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr));
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num = blk_bio_map_sg(q, bio, vbr->sg + out);
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sg_set_buf(&vbr->sg[num + out + in++], &vbr->status,
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sizeof(vbr->status));
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if (num) {
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if (bio->bi_rw & REQ_WRITE) {
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vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
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out += num;
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} else {
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vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
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in += num;
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}
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}
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spin_lock_irq(vblk->disk->queue->queue_lock);
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if (unlikely(virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
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GFP_ATOMIC) < 0)) {
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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virtblk_add_buf_wait(vblk, vbr, out, in);
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return;
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}
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virtqueue_kick(vblk->vq);
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spin_unlock_irq(vblk->disk->queue->queue_lock);
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if (unlikely(vbr->flags & VBLK_REQ_FLUSH))
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virtblk_bio_send_flush(vbr);
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else
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virtblk_bio_send_data(vbr);
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}
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/* return id (s/n) string for *disk to *id_str
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@ -529,7 +633,7 @@ static void virtblk_update_cache_mode(struct virtio_device *vdev)
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u8 writeback = virtblk_get_cache_mode(vdev);
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struct virtio_blk *vblk = vdev->priv;
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if (writeback && !use_bio)
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if (writeback)
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blk_queue_flush(vblk->disk->queue, REQ_FLUSH);
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else
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blk_queue_flush(vblk->disk->queue, 0);
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