[RFC PATCH V2 1/8] vhost: move get_rx_bufs to vhost.c

[Jason Wang]

Move get_rx_bufs() to vhost.c and rename it to
vhost_get_rx_bufs(). This helps to hide vring internal layout from
specific device implementation. Packed ring implementation will
benefit from this.

Signed-off-by: Jason Wang 
---
 drivers/vhost/net.c   | 83 ++-
 drivers/vhost/vhost.c | 78 +++
 drivers/vhost/vhost.h |  7 +
 3 files changed, 88 insertions(+), 80 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 8139bc7..57dfa63 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -658,83 +658,6 @@ static int vhost_net_rx_peek_head_len(struct vhost_net 
*net, struct sock *sk)
return len;
 }
 
-/* This is a multi-buffer version of vhost_get_desc, that works if
- * vq has read descriptors only.
- * @vq - the relevant virtqueue
- * @datalen- data length we'll be reading
- * @iovcount   - returned count of io vectors we fill
- * @log- vhost log
- * @log_num- log offset
- * @quota   - headcount quota, 1 for big buffer
- * returns number of buffer heads allocated, negative on error
- */
-static int get_rx_bufs(struct vhost_virtqueue *vq,
-  struct vring_used_elem *heads,
-  int datalen,
-  unsigned *iovcount,
-  struct vhost_log *log,
-  unsigned *log_num,
-  unsigned int quota)
-{
-   unsigned int out, in;
-   int seg = 0;
-   int headcount = 0;
-   unsigned d;
-   int r, nlogs = 0;
-   /* len is always initialized before use since we are always called with
-* datalen > 0.
-*/
-   u32 uninitialized_var(len);
-
-   while (datalen > 0 && headcount < quota) {
-   if (unlikely(seg >= UIO_MAXIOV)) {
-   r = -ENOBUFS;
-   goto err;
-   }
-   r = vhost_get_vq_desc(vq, vq->iov + seg,
- ARRAY_SIZE(vq->iov) - seg, ,
- , log, log_num);
-   if (unlikely(r < 0))
-   goto err;
-
-   d = r;
-   if (d == vq->num) {
-   r = 0;
-   goto err;
-   }
-   if (unlikely(out || in <= 0)) {
-   vq_err(vq, "unexpected descriptor format for RX: "
-   "out %d, in %d\n", out, in);
-   r = -EINVAL;
-   goto err;
-   }
-   if (unlikely(log)) {
-   nlogs += *log_num;
-   log += *log_num;
-   }
-   heads[headcount].id = cpu_to_vhost32(vq, d);
-   len = iov_length(vq->iov + seg, in);
-   heads[headcount].len = cpu_to_vhost32(vq, len);
-   datalen -= len;
-   ++headcount;
-   seg += in;
-   }
-   heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
-   *iovcount = seg;
-   if (unlikely(log))
-   *log_num = nlogs;
-
-   /* Detect overrun */
-   if (unlikely(datalen > 0)) {
-   r = UIO_MAXIOV + 1;
-   goto err;
-   }
-   return headcount;
-err:
-   vhost_discard_vq_desc(vq, headcount);
-   return r;
-}
-
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
 static void handle_rx(struct vhost_net *net)
@@ -784,9 +707,9 @@ static void handle_rx(struct vhost_net *net)
while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) {
sock_len += sock_hlen;
vhost_len = sock_len + vhost_hlen;
-   headcount = get_rx_bufs(vq, vq->heads + nheads, vhost_len,
-   , vq_log, ,
-   likely(mergeable) ? UIO_MAXIOV : 1);
+   headcount = vhost_get_bufs(vq, vq->heads + nheads, vhost_len,
+  , vq_log, ,
+  likely(mergeable) ? UIO_MAXIOV : 1);
/* On error, stop handling until the next kick. */
if (unlikely(headcount < 0))
goto out;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 1b3e8d2d..c57df71 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2098,6 +2098,84 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
+/* This is a multi-buffer version of vhost_get_desc, that works if
+ * vq has read descriptors only.
+ * @vq - the relevant virtqueue
+ * @datalen- data length we'll be reading
+ * @iovcount   - returned count of io vectors we fill
+ * @log- vhost log
+ * @log_num- log offset
+ * 

[RFC PATCH V2 1/8] vhost: move get_rx_bufs to vhost.c

[Jason Wang]

Move get_rx_bufs() to vhost.c and rename it to
vhost_get_rx_bufs(). This helps to hide vring internal layout from
specific device implementation. Packed ring implementation will
benefit from this.

Signed-off-by: Jason Wang 
---
 drivers/vhost/net.c   | 83 ++-
 drivers/vhost/vhost.c | 78 +++
 drivers/vhost/vhost.h |  7 +
 3 files changed, 88 insertions(+), 80 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 8139bc7..57dfa63 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -658,83 +658,6 @@ static int vhost_net_rx_peek_head_len(struct vhost_net 
*net, struct sock *sk)
return len;
 }
 
-/* This is a multi-buffer version of vhost_get_desc, that works if
- * vq has read descriptors only.
- * @vq - the relevant virtqueue
- * @datalen- data length we'll be reading
- * @iovcount   - returned count of io vectors we fill
- * @log- vhost log
- * @log_num- log offset
- * @quota   - headcount quota, 1 for big buffer
- * returns number of buffer heads allocated, negative on error
- */
-static int get_rx_bufs(struct vhost_virtqueue *vq,
-  struct vring_used_elem *heads,
-  int datalen,
-  unsigned *iovcount,
-  struct vhost_log *log,
-  unsigned *log_num,
-  unsigned int quota)
-{
-   unsigned int out, in;
-   int seg = 0;
-   int headcount = 0;
-   unsigned d;
-   int r, nlogs = 0;
-   /* len is always initialized before use since we are always called with
-* datalen > 0.
-*/
-   u32 uninitialized_var(len);
-
-   while (datalen > 0 && headcount < quota) {
-   if (unlikely(seg >= UIO_MAXIOV)) {
-   r = -ENOBUFS;
-   goto err;
-   }
-   r = vhost_get_vq_desc(vq, vq->iov + seg,
- ARRAY_SIZE(vq->iov) - seg, ,
- , log, log_num);
-   if (unlikely(r < 0))
-   goto err;
-
-   d = r;
-   if (d == vq->num) {
-   r = 0;
-   goto err;
-   }
-   if (unlikely(out || in <= 0)) {
-   vq_err(vq, "unexpected descriptor format for RX: "
-   "out %d, in %d\n", out, in);
-   r = -EINVAL;
-   goto err;
-   }
-   if (unlikely(log)) {
-   nlogs += *log_num;
-   log += *log_num;
-   }
-   heads[headcount].id = cpu_to_vhost32(vq, d);
-   len = iov_length(vq->iov + seg, in);
-   heads[headcount].len = cpu_to_vhost32(vq, len);
-   datalen -= len;
-   ++headcount;
-   seg += in;
-   }
-   heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
-   *iovcount = seg;
-   if (unlikely(log))
-   *log_num = nlogs;
-
-   /* Detect overrun */
-   if (unlikely(datalen > 0)) {
-   r = UIO_MAXIOV + 1;
-   goto err;
-   }
-   return headcount;
-err:
-   vhost_discard_vq_desc(vq, headcount);
-   return r;
-}
-
 /* Expects to be always run from workqueue - which acts as
  * read-size critical section for our kind of RCU. */
 static void handle_rx(struct vhost_net *net)
@@ -784,9 +707,9 @@ static void handle_rx(struct vhost_net *net)
while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) {
sock_len += sock_hlen;
vhost_len = sock_len + vhost_hlen;
-   headcount = get_rx_bufs(vq, vq->heads + nheads, vhost_len,
-   , vq_log, ,
-   likely(mergeable) ? UIO_MAXIOV : 1);
+   headcount = vhost_get_bufs(vq, vq->heads + nheads, vhost_len,
+  , vq_log, ,
+  likely(mergeable) ? UIO_MAXIOV : 1);
/* On error, stop handling until the next kick. */
if (unlikely(headcount < 0))
goto out;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 1b3e8d2d..c57df71 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2098,6 +2098,84 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
+/* This is a multi-buffer version of vhost_get_desc, that works if
+ * vq has read descriptors only.
+ * @vq - the relevant virtqueue
+ * @datalen- data length we'll be reading
+ * @iovcount   - returned count of io vectors we fill
+ * @log- vhost log
+ * @log_num- log offset
+ * @quota   -