virtio: add_buf_gfp

Add an add_buf variant that gets gfp parameter. Use that
to allocate indirect buffers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

2 files changed, 28 insertions, 14 deletions

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 0717b5b000bb..1ca88908723b 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -110,13 +110,14 @@ struct vring_virtqueue
 static int vring_add_indirect(struct vring_virtqueue *vq,
                               struct scatterlist sg[],
                               unsigned int out,
-                              unsigned int in)
+                              unsigned int in,
+                              gfp_t gfp)
 {
         struct vring_desc *desc;
         unsigned head;
         int i;
 
-        desc = kmalloc((out + in) * sizeof(struct vring_desc), GFP_ATOMIC);
+        desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp);
         if (!desc)
                 return vq->vring.num;
 
@@ -155,11 +156,12 @@ static int vring_add_indirect(struct vring_virtqueue *vq,
         return head;
 }
 
-int virtqueue_add_buf(struct virtqueue *_vq,
-                  struct scatterlist sg[],
-                  unsigned int out,
-                  unsigned int in,
-                  void *data)
+int virtqueue_add_buf_gfp(struct virtqueue *_vq,
+                          struct scatterlist sg[],
+                          unsigned int out,
+                          unsigned int in,
+                          void *data,
+                          gfp_t gfp)
 {
         struct vring_virtqueue *vq = to_vvq(_vq);
         unsigned int i, avail, head, uninitialized_var(prev);
@@ -171,7 +173,7 @@ int virtqueue_add_buf(struct virtqueue *_vq,
         /* If the host supports indirect descriptor tables, and we have multiple
          * buffers, then go indirect. FIXME: tune this threshold */
         if (vq->indirect && (out + in) > 1 && vq->num_free) {
-                head = vring_add_indirect(vq, sg, out, in);
+                head = vring_add_indirect(vq, sg, out, in, gfp);
                 if (head != vq->vring.num)
                         goto add_head;
         }
@@ -232,7 +234,7 @@ add_head:
                 return vq->num_free ? vq->vring.num : 0;
         return vq->num_free;
 }
-EXPORT_SYMBOL_GPL(virtqueue_add_buf);
+EXPORT_SYMBOL_GPL(virtqueue_add_buf_gfp);
 
 void virtqueue_kick(struct virtqueue *_vq)
 {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 5b0fce0d2aa2..aff5b4f74041 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -7,6 +7,7 @@
 #include <linux/spinlock.h>
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
+#include <linux/gfp.h>
 
 /**
  * virtqueue - a queue to register buffers for sending or receiving.
@@ -32,6 +33,7 @@ struct virtqueue {
  *      out_num: the number of sg readable by other side
  *      in_num: the number of sg which are writable (after readable ones)
  *      data: the token identifying the buffer.
+ *      gfp: how to do memory allocations (if necessary).
  *      Returns remaining capacity of queue (sg segments) or a negative error.
  * virtqueue_kick: update after add_buf
  *      vq: the struct virtqueue
@@ -60,11 +62,21 @@ struct virtqueue {
  * All operations can be called in any context.
  */
 
-int virtqueue_add_buf(struct virtqueue *vq,
-                      struct scatterlist sg[],
-                      unsigned int out_num,
-                      unsigned int in_num,
-                      void *data);
+int virtqueue_add_buf_gfp(struct virtqueue *vq,
+                          struct scatterlist sg[],
+                          unsigned int out_num,
+                          unsigned int in_num,
+                          void *data,
+                          gfp_t gfp);
+
+static inline int virtqueue_add_buf(struct virtqueue *vq,
+                                    struct scatterlist sg[],
+                                    unsigned int out_num,
+                                    unsigned int in_num,
+                                    void *data)
+{
+        return virtqueue_add_buf_gfp(vq, sg, out_num, in_num, data, GFP_ATOMIC);
+}
 
 void virtqueue_kick(struct virtqueue *vq);