SUNRPC: skb_read_bits is the same as xs_tcp_copy_data

Clean-up: eliminate xs_tcp_copy_data -- it's exactly the same logic as the
common routine skb_read_bits.  The UDP and TCP socket read code now share
the same routine for copying data into an xdr_buf.

Now that skb_read_bits() is exported, rename it to avoid confusing it with
a generic skb_* function.  As these functions are XDR-specific, they should
not have names that suggest they are of generic use.  Also rename
skb_read_and_csum_bits() to be consistent.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/sunrpc/xdr.h

@@ -157,6 +157,7 @@ typedef struct {
 
 typedef size_t (*skb_read_actor_t)(skb_reader_t *desc, void *to, size_t len);
 
+size_t xdr_skb_read_bits(skb_reader_t *desc, void *to, size_t len);
 extern int csum_partial_copy_to_xdr(struct xdr_buf *, struct sk_buff *);
 extern ssize_t xdr_partial_copy_from_skb(struct xdr_buf *, unsigned int,
 		skb_reader_t *, skb_read_actor_t);

net/sunrpc/socklib.c

@@ -16,7 +16,7 @@
 
 
 /**
- * skb_read_bits - copy some data bits from skb to internal buffer
+ * xdr_skb_read_bits - copy some data bits from skb to internal buffer
  * @desc: sk_buff copy helper
  * @to: copy destination
  * @len: number of bytes to copy
@@ -24,11 +24,11 @@
  * Possibly called several times to iterate over an sk_buff and copy
  * data out of it.
  */
-static size_t skb_read_bits(skb_reader_t *desc, void *to, size_t len)
+size_t xdr_skb_read_bits(skb_reader_t *desc, void *to, size_t len)
 {
 	if (len > desc->count)
 		len = desc->count;
-	if (skb_copy_bits(desc->skb, desc->offset, to, len))
+	if (unlikely(skb_copy_bits(desc->skb, desc->offset, to, len)))
 		return 0;
 	desc->count -= len;
 	desc->offset += len;
@@ -36,14 +36,14 @@ static size_t skb_read_bits(skb_reader_t *desc, void *to, size_t len)
 }
 
 /**
- * skb_read_and_csum_bits - copy and checksum from skb to buffer
+ * xdr_skb_read_and_csum_bits - copy and checksum from skb to buffer
  * @desc: sk_buff copy helper
  * @to: copy destination
  * @len: number of bytes to copy
  *
  * Same as skb_read_bits, but calculate a checksum at the same time.
  */
-static size_t skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len)
+static size_t xdr_skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len)
 {
 	unsigned int pos;
 	__wsum csum2;
@@ -158,7 +158,7 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
 		goto no_checksum;
 
 	desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
-	if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits) < 0)
+	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_and_csum_bits) < 0)
 		return -1;
 	if (desc.offset != skb->len) {
 		__wsum csum2;
@@ -173,7 +173,7 @@ int csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
 		netdev_rx_csum_fault(skb->dev);
 	return 0;
 no_checksum:
-	if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits) < 0)
+	if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
 		return -1;
 	if (desc.count)
 		return -1;

net/sunrpc/xprtsock.c

@@ -651,22 +651,6 @@ static void xs_udp_data_ready(struct sock *sk, int len)
 	read_unlock(&sk->sk_callback_lock);
 }
 
-static inline size_t xs_tcp_copy_data(skb_reader_t *desc, void *p, size_t len)
-{
-	if (len > desc->count)
-		len = desc->count;
-	if (skb_copy_bits(desc->skb, desc->offset, p, len)) {
-		dprintk("RPC:      failed to copy %zu bytes from skb. %zu bytes remain\n",
-				len, desc->count);
-		return 0;
-	}
-	desc->offset += len;
-	desc->count -= len;
-	dprintk("RPC:      copied %zu bytes from skb. %zu bytes remain\n",
-			len, desc->count);
-	return len;
-}
-
 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, skb_reader_t *desc)
 {
 	struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
@@ -675,7 +659,7 @@ static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, skb_reader_t *desc
 
 	p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
 	len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
-	used = xs_tcp_copy_data(desc, p, len);
+	used = xdr_skb_read_bits(desc, p, len);
 	transport->tcp_offset += used;
 	if (used != len)
 		return;
@@ -721,7 +705,7 @@ static inline void xs_tcp_read_xid(struct sock_xprt *transport, skb_reader_t *de
 	len = sizeof(transport->tcp_xid) - transport->tcp_offset;
 	dprintk("RPC:      reading XID (%Zu bytes)\n", len);
 	p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
-	used = xs_tcp_copy_data(desc, p, len);
+	used = xdr_skb_read_bits(desc, p, len);
 	transport->tcp_offset += used;
 	if (used != len)
 		return;
@@ -761,12 +745,12 @@ static inline void xs_tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc
 		memcpy(&my_desc, desc, sizeof(my_desc));
 		my_desc.count = len;
 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
-					  &my_desc, xs_tcp_copy_data);
+					  &my_desc, xdr_skb_read_bits);
 		desc->count -= r;
 		desc->offset += r;
 	} else
 		r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
-					  desc, xs_tcp_copy_data);
+					  desc, xdr_skb_read_bits);
 
 	if (r > 0) {
 		transport->tcp_copied += r;