skbuff: struct ubuf_info callback type safety

The skb struct ubuf_info callback gets passed struct ubuf_info
itself, not the arg value as the field name and the function signature
seem to imply. Rename the arg field to ctx to match usage,
add documentation and change the callback argument type
to make usage clear and to have compiler check correctness.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f0da2c32fbdefce2ff9d791f9fa23a73ac49de8d..1f21d2a1e52885af8db0a691170b8ab0364aa7b4 100644 (file)
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -238,7 +238,7 @@ static void handle_tx(struct vhost_net *net)
 
                                vq->heads[vq->upend_idx].len = len;
                                ubuf->callback = vhost_zerocopy_callback;
-                               ubuf->arg = vq->ubufs;
+                               ubuf->ctx = vq->ubufs;
                                ubuf->desc = vq->upend_idx;
                                msg.msg_control = ubuf;
                                msg.msg_controllen = sizeof(ubuf);

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 947f00d8e091a3f2f3c01cc7cc23f5f2658d37df..51e4c1eeec4f0b09af84b5feb58c63313cd7d0cb 100644 (file)
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1598,10 +1598,9 @@ void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
        kfree(ubufs);
 }
 
-void vhost_zerocopy_callback(void *arg)
+void vhost_zerocopy_callback(struct ubuf_info *ubuf)
 {
-       struct ubuf_info *ubuf = arg;
-       struct vhost_ubuf_ref *ubufs = ubuf->arg;
+       struct vhost_ubuf_ref *ubufs = ubuf->ctx;
        struct vhost_virtqueue *vq = ubufs->vq;
 
        /* set len = 1 to mark this desc buffers done DMA */

diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 8dcf4cca6bf224ec5c36f105a994ba76b0b19188..8de1fd5b8efba8a39c20e7872a23b517e710b9ec 100644 (file)
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -188,7 +188,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct vhost_virtqueue *);
 
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
                    unsigned int log_num, u64 len);
-void vhost_zerocopy_callback(void *arg);
+void vhost_zerocopy_callback(struct ubuf_info *);
 int vhost_zerocopy_signal_used(struct vhost_virtqueue *vq);
 
 #define vq_err(vq, fmt, ...) do {                                  \

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 70a3f8d49118599510af86a6ef1022a0c064c850..775292a66fa4d84615e2b3d3d15c84913cc7813b 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -238,11 +238,12 @@ enum {
 /*
  * The callback notifies userspace to release buffers when skb DMA is done in
  * lower device, the skb last reference should be 0 when calling this.
- * The desc is used to track userspace buffer index.
+ * The ctx field is used to track device context.
+ * The desc field is used to track userspace buffer index.
  */
 struct ubuf_info {
-       void (*callback)(void *);
-       void *arg;
+       void (*callback)(struct ubuf_info *);
+       void *ctx;
        unsigned long desc;
 };