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Subject[PATCH net-next v3 07/13] virtio_ring: allocate desc state for split ring separately
Date
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>
---
drivers/virtio/virtio_ring.c | 45 ++++++++++++++++++++++++++------------------
1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index d1076f28c7e9..acd851f3105c 100644
--- 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);
--
2.14.5
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