virtio_ring: allocate desc state for split ring separately

Put the split ring's desc state into the .split sub-structure,
and allocate desc state for split ring separately, this makes
the code more readable and more consistent with what we will
do for packed ring.

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index d1076f28c7e97c9bc38ea2c2b7a10bb7fe25f9cb..acd851f3105c4707906d83ee35aa94ffea767ec7 100644 (file)
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -78,7 +78,7 @@
 #define LAST_ADD_TIME_INVALID(vq)
 #endif
 
-struct vring_desc_state {
+struct vring_desc_state_split {
        void *data;                     /* Data for callback. */
        struct vring_desc *indir_desc;  /* Indirect descriptor, if any. */
 };
@@ -115,6 +115,9 @@ struct vring_virtqueue {
 
                /* Last written value to avail->idx in guest byte order */
                u16 avail_idx_shadow;
+
+               /* Per-descriptor state. */
+               struct vring_desc_state_split *desc_state;
        } split;
 
        /* How to notify other side. FIXME: commonalize hcalls! */
@@ -133,9 +136,6 @@ struct vring_virtqueue {
        bool last_add_time_valid;
        ktime_t last_add_time;
 #endif
-
-       /* Per-descriptor state. */
-       struct vring_desc_state desc_state[];
 };
 
 
@@ -427,11 +427,11 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
                vq->free_head = i;
 
        /* Store token and indirect buffer state. */
-       vq->desc_state[head].data = data;
+       vq->split.desc_state[head].data = data;
        if (indirect)
-               vq->desc_state[head].indir_desc = desc;
+               vq->split.desc_state[head].indir_desc = desc;
        else
-               vq->desc_state[head].indir_desc = ctx;
+               vq->split.desc_state[head].indir_desc = ctx;
 
        /* Put entry in available array (but don't update avail->idx until they
         * do sync). */
@@ -512,7 +512,7 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
        __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
 
        /* Clear data ptr. */
-       vq->desc_state[head].data = NULL;
+       vq->split.desc_state[head].data = NULL;
 
        /* Put back on free list: unmap first-level descriptors and find end */
        i = head;
@@ -532,7 +532,8 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
        vq->vq.num_free++;
 
        if (vq->indirect) {
-               struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
+               struct vring_desc *indir_desc =
+                               vq->split.desc_state[head].indir_desc;
                u32 len;
 
                /* Free the indirect table, if any, now that it's unmapped. */
@@ -550,9 +551,9 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
                        vring_unmap_one_split(vq, &indir_desc[j]);
 
                kfree(indir_desc);
-               vq->desc_state[head].indir_desc = NULL;
+               vq->split.desc_state[head].indir_desc = NULL;
        } else if (ctx) {
-               *ctx = vq->desc_state[head].indir_desc;
+               *ctx = vq->split.desc_state[head].indir_desc;
        }
 }
 
@@ -597,13 +598,13 @@ static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq,
                BAD_RING(vq, "id %u out of range\n", i);
                return NULL;
        }
-       if (unlikely(!vq->desc_state[i].data)) {
+       if (unlikely(!vq->split.desc_state[i].data)) {
                BAD_RING(vq, "id %u is not a head!\n", i);
                return NULL;
        }
 
        /* detach_buf_split clears data, so grab it now. */
-       ret = vq->desc_state[i].data;
+       ret = vq->split.desc_state[i].data;
        detach_buf_split(vq, i, ctx);
        vq->last_used_idx++;
        /* If we expect an interrupt for the next entry, tell host
@@ -711,10 +712,10 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
        START_USE(vq);
 
        for (i = 0; i < vq->split.vring.num; i++) {
-               if (!vq->desc_state[i].data)
+               if (!vq->split.desc_state[i].data)
                        continue;
                /* detach_buf_split clears data, so grab it now. */
-               buf = vq->desc_state[i].data;
+               buf = vq->split.desc_state[i].data;
                detach_buf_split(vq, i, NULL);
                vq->split.avail_idx_shadow--;
                vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
@@ -1080,8 +1081,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
        unsigned int i;
        struct vring_virtqueue *vq;
 
-       vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state),
-                    GFP_KERNEL);
+       vq = kmalloc(sizeof(*vq), GFP_KERNEL);
        if (!vq)
                return NULL;
 
@@ -1120,11 +1120,19 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
                                        vq->split.avail_flags_shadow);
        }
 
+       vq->split.desc_state = kmalloc_array(vring.num,
+                       sizeof(struct vring_desc_state_split), GFP_KERNEL);
+       if (!vq->split.desc_state) {
+               kfree(vq);
+               return NULL;
+       }
+
        /* Put everything in free lists. */
        vq->free_head = 0;
        for (i = 0; i < vring.num-1; i++)
                vq->split.vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
-       memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state));
+       memset(vq->split.desc_state, 0, vring.num *
+                       sizeof(struct vring_desc_state_split));
 
        return &vq->vq;
 }
@@ -1260,6 +1268,7 @@ void vring_del_virtqueue(struct virtqueue *_vq)
        if (vq->we_own_ring) {
                vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes,
                                 vq->split.vring.desc, vq->queue_dma_addr);
+               kfree(vq->split.desc_state);
        }
        list_del(&_vq->list);
        kfree(vq);