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Subject[RFC PATCH 2/8] virtio-blk: reorganize virtblk_add_req
Date
Right now, both virtblk_add_req and virtblk_add_req_wait call
virtqueue_add_buf. To prepare for the next patches, abstract the call
to virtqueue_add_buf into a new function __virtblk_add_req, and include
the waiting logic directly in virtblk_add_req.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
drivers/block/virtio_blk.c | 55 ++++++++++++++++----------------------------
1 files changed, 20 insertions(+), 35 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 8ad21a2..fd8a689 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -100,50 +100,39 @@ static inline struct virtblk_req *virtblk_alloc_req(struct virtio_blk *vblk,
return vbr;
}

-static void virtblk_add_buf_wait(struct virtio_blk *vblk,
- struct virtblk_req *vbr,
- unsigned long out,
- unsigned long in)
+static inline int __virtblk_add_req(struct virtqueue *vq,
+ struct virtblk_req *vbr,
+ unsigned long out,
+ unsigned long in)
{
+ return virtqueue_add_buf(vq, vbr->sg, out, in, vbr, GFP_ATOMIC);
+}
+
+static void virtblk_add_req(struct virtblk_req *vbr,
+ unsigned int out, unsigned int in)
+{
+ struct virtio_blk *vblk = vbr->vblk;
DEFINE_WAIT(wait);
+ int ret;

- for (;;) {
+ spin_lock_irq(vblk->disk->queue->queue_lock);
+ while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr,
+ out, in)) < 0)) {
prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
TASK_UNINTERRUPTIBLE);

+ spin_unlock_irq(vblk->disk->queue->queue_lock);
+ io_schedule();
spin_lock_irq(vblk->disk->queue->queue_lock);
- if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
- GFP_ATOMIC) < 0) {
- spin_unlock_irq(vblk->disk->queue->queue_lock);
- io_schedule();
- } else {
- virtqueue_kick(vblk->vq);
- spin_unlock_irq(vblk->disk->queue->queue_lock);
- break;
- }

+ finish_wait(&vblk->queue_wait, &wait);
}

- finish_wait(&vblk->queue_wait, &wait);
-}
-
-static inline void virtblk_add_req(struct virtblk_req *vbr,
- unsigned int out, unsigned int in)
-{
- struct virtio_blk *vblk = vbr->vblk;
-
- spin_lock_irq(vblk->disk->queue->queue_lock);
- if (unlikely(virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
- GFP_ATOMIC) < 0)) {
- spin_unlock_irq(vblk->disk->queue->queue_lock);
- virtblk_add_buf_wait(vblk, vbr, out, in);
- return;
- }
virtqueue_kick(vblk->vq);
spin_unlock_irq(vblk->disk->queue->queue_lock);
}

-static int virtblk_bio_send_flush(struct virtblk_req *vbr)
+static void virtblk_bio_send_flush(struct virtblk_req *vbr)
{
unsigned int out = 0, in = 0;

@@ -155,11 +144,9 @@ static int virtblk_bio_send_flush(struct virtblk_req *vbr)
sg_set_buf(&vbr->sg[out + in++], &vbr->status, sizeof(vbr->status));

virtblk_add_req(vbr, out, in);
-
- return 0;
}

-static int virtblk_bio_send_data(struct virtblk_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;
@@ -188,8 +175,6 @@ static int virtblk_bio_send_data(struct virtblk_req *vbr)
}

virtblk_add_req(vbr, out, in);
-
- return 0;
}

static void virtblk_bio_send_data_work(struct work_struct *work)
--
1.7.1



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