virtio_ring: extract split ring handling from ring creation

Introduce a specific function to create the split ring.
And also move the DMA allocation and size information to
the .split sub-structure.

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

1 files changed, 121 insertions, 99 deletions

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index acd851f3105c..d00a87909a7e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -118,6 +118,10 @@ struct vring_virtqueue {
 
                 /* Per-descriptor state. */
                 struct vring_desc_state_split *desc_state;
+
+                /* DMA, allocation, and size information */
+                size_t queue_size_in_bytes;
+                dma_addr_t queue_dma_addr;
         } split;
 
         /* How to notify other side. FIXME: commonalize hcalls! */
@@ -125,8 +129,6 @@ struct vring_virtqueue {
 
         /* DMA, allocation, and size information */
         bool we_own_ring;
-        size_t queue_size_in_bytes;
-        dma_addr_t queue_dma_addr;
 
 #ifdef DEBUG
         /* They're supposed to lock for us. */
@@ -203,6 +205,48 @@ static bool vring_use_dma_api(struct virtio_device *vdev)
         return false;
 }
 
+static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
+                              dma_addr_t *dma_handle, gfp_t flag)
+{
+        if (vring_use_dma_api(vdev)) {
+                return dma_alloc_coherent(vdev->dev.parent, size,
+                                          dma_handle, flag);
+        } else {
+                void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
+
+                if (queue) {
+                        phys_addr_t phys_addr = virt_to_phys(queue);
+                        *dma_handle = (dma_addr_t)phys_addr;
+
+                        /*
+                         * Sanity check: make sure we dind't truncate
+                         * the address.  The only arches I can find that
+                         * have 64-bit phys_addr_t but 32-bit dma_addr_t
+                         * are certain non-highmem MIPS and x86
+                         * configurations, but these configurations
+                         * should never allocate physical pages above 32
+                         * bits, so this is fine.  Just in case, throw a
+                         * warning and abort if we end up with an
+                         * unrepresentable address.
+                         */
+                        if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
+                                free_pages_exact(queue, PAGE_ALIGN(size));
+                                return NULL;
+                        }
+                }
+                return queue;
+        }
+}
+
+static void vring_free_queue(struct virtio_device *vdev, size_t size,
+                             void *queue, dma_addr_t dma_handle)
+{
+        if (vring_use_dma_api(vdev))
+                dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
+        else
+                free_pages_exact(queue, PAGE_ALIGN(size));
+}
+
 /*
  * The DMA ops on various arches are rather gnarly right now, and
  * making all of the arch DMA ops work on the vring device itself
@@ -730,6 +774,68 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
         return NULL;
 }
 
+static struct virtqueue *vring_create_virtqueue_split(
+        unsigned int index,
+        unsigned int num,
+        unsigned int vring_align,
+        struct virtio_device *vdev,
+        bool weak_barriers,
+        bool may_reduce_num,
+        bool context,
+        bool (*notify)(struct virtqueue *),
+        void (*callback)(struct virtqueue *),
+        const char *name)
+{
+        struct virtqueue *vq;
+        void *queue = NULL;
+        dma_addr_t dma_addr;
+        size_t queue_size_in_bytes;
+        struct vring vring;
+
+        /* We assume num is a power of 2. */
+        if (num & (num - 1)) {
+                dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
+                return NULL;
+        }
+
+        /* TODO: allocate each queue chunk individually */
+        for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
+                queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
+                                          &dma_addr,
+                                          GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
+                if (queue)
+                        break;
+        }
+
+        if (!num)
+                return NULL;
+
+        if (!queue) {
+                /* Try to get a single page. You are my only hope! */
+                queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
+                                          &dma_addr, GFP_KERNEL|__GFP_ZERO);
+        }
+        if (!queue)
+                return NULL;
+
+        queue_size_in_bytes = vring_size(num, vring_align);
+        vring_init(&vring, num, queue, vring_align);
+
+        vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
+                                   notify, callback, name);
+        if (!vq) {
+                vring_free_queue(vdev, queue_size_in_bytes, queue,
+                                 dma_addr);
+                return NULL;
+        }
+
+        to_vvq(vq)->split.queue_dma_addr = dma_addr;
+        to_vvq(vq)->split.queue_size_in_bytes = queue_size_in_bytes;
+        to_vvq(vq)->we_own_ring = true;
+
+        return vq;
+}
+
 
 /*
  * Generic functions and exported symbols.
@@ -1091,8 +1197,6 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
         vq->vq.num_free = vring.num;
         vq->vq.index = index;
         vq->we_own_ring = false;
-        vq->queue_dma_addr = 0;
-        vq->queue_size_in_bytes = 0;
         vq->notify = notify;
         vq->weak_barriers = weak_barriers;
         vq->broken = false;
@@ -1108,6 +1212,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
                 !context;
         vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
 
+        vq->split.queue_dma_addr = 0;
+        vq->split.queue_size_in_bytes = 0;
+
         vq->split.vring = vring;
         vq->split.avail_flags_shadow = 0;
         vq->split.avail_idx_shadow = 0;
@@ -1138,48 +1245,6 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index,
 }
 EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
 
-static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
-                              dma_addr_t *dma_handle, gfp_t flag)
-{
-        if (vring_use_dma_api(vdev)) {
-                return dma_alloc_coherent(vdev->dev.parent, size,
-                                          dma_handle, flag);
-        } else {
-                void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
-                if (queue) {
-                        phys_addr_t phys_addr = virt_to_phys(queue);
-                        *dma_handle = (dma_addr_t)phys_addr;
-
-                        /*
-                         * Sanity check: make sure we dind't truncate
-                         * the address.  The only arches I can find that
-                         * have 64-bit phys_addr_t but 32-bit dma_addr_t
-                         * are certain non-highmem MIPS and x86
-                         * configurations, but these configurations
-                         * should never allocate physical pages above 32
-                         * bits, so this is fine.  Just in case, throw a
-                         * warning and abort if we end up with an
-                         * unrepresentable address.
-                         */
-                        if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
-                                free_pages_exact(queue, PAGE_ALIGN(size));
-                                return NULL;
-                        }
-                }
-                return queue;
-        }
-}
-
-static void vring_free_queue(struct virtio_device *vdev, size_t size,
-                             void *queue, dma_addr_t dma_handle)
-{
-        if (vring_use_dma_api(vdev)) {
-                dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
-        } else {
-                free_pages_exact(queue, PAGE_ALIGN(size));
-        }
-}
-
 struct virtqueue *vring_create_virtqueue(
         unsigned int index,
         unsigned int num,
@@ -1192,54 +1257,9 @@ struct virtqueue *vring_create_virtqueue(
         void (*callback)(struct virtqueue *),
         const char *name)
 {
-        struct virtqueue *vq;
-        void *queue = NULL;
-        dma_addr_t dma_addr;
-        size_t queue_size_in_bytes;
-        struct vring vring;
-
-        /* We assume num is a power of 2. */
-        if (num & (num - 1)) {
-                dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
-                return NULL;
-        }
-
-        /* TODO: allocate each queue chunk individually */
-        for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
-                queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
-                                          &dma_addr,
-                                          GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
-                if (queue)
-                        break;
-        }
-
-        if (!num)
-                return NULL;
-
-        if (!queue) {
-                /* Try to get a single page. You are my only hope! */
-                queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
-                                          &dma_addr, GFP_KERNEL|__GFP_ZERO);
-        }
-        if (!queue)
-                return NULL;
-
-        queue_size_in_bytes = vring_size(num, vring_align);
-        vring_init(&vring, num, queue, vring_align);
-
-        vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
-                                   notify, callback, name);
-        if (!vq) {
-                vring_free_queue(vdev, queue_size_in_bytes, queue,
-                                 dma_addr);
-                return NULL;
-        }
-
-        to_vvq(vq)->queue_dma_addr = dma_addr;
-        to_vvq(vq)->queue_size_in_bytes = queue_size_in_bytes;
-        to_vvq(vq)->we_own_ring = true;
-
-        return vq;
+        return vring_create_virtqueue_split(index, num, vring_align,
+                        vdev, weak_barriers, may_reduce_num,
+                        context, notify, callback, name);
 }
 EXPORT_SYMBOL_GPL(vring_create_virtqueue);
 
@@ -1266,8 +1286,10 @@ void vring_del_virtqueue(struct virtqueue *_vq)
         struct vring_virtqueue *vq = to_vvq(_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);
+                vring_free_queue(vq->vq.vdev,
+                                 vq->split.queue_size_in_bytes,
+                                 vq->split.vring.desc,
+                                 vq->split.queue_dma_addr);
                 kfree(vq->split.desc_state);
         }
         list_del(&_vq->list);
@@ -1343,7 +1365,7 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
 
         BUG_ON(!vq->we_own_ring);
 
-        return vq->queue_dma_addr;
+        return vq->split.queue_dma_addr;
 }
 EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
 
@@ -1353,7 +1375,7 @@ dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
 
         BUG_ON(!vq->we_own_ring);
 
-        return vq->queue_dma_addr +
+        return vq->split.queue_dma_addr +
                 ((char *)vq->split.vring.avail - (char *)vq->split.vring.desc);
 }
 EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
@@ -1364,7 +1386,7 @@ dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
 
         BUG_ON(!vq->we_own_ring);
 
-        return vq->queue_dma_addr +
+        return vq->split.queue_dma_addr +
                 ((char *)vq->split.vring.used - (char *)vq->split.vring.desc);
 }
 EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);