If an error is returned after the first bits of a packet have already been
successfully queued, xs_sendpages() will return a positive 'int' value
indicating success. Callers seem to treat this as -EAGAIN.
However, there are cases where its not a question of waiting for the write
queue to drain. For example, when there is an iptables rule dropping packets
to the destination, the lower level code can return -EPERM only after parts
of the packet have been successfully queued. In this case, we can end up
continuously retrying.
This patch is meant to effectively be a no-op in preparation for subsequent
patches that can make decisions based on both on the number of bytes sent
by xs_sendpages() and any errors that may have be returned.
Signed-off-by: Jason Baron <jbaron@xxxxxxxxxx>
---
net/sunrpc/xprtsock.c | 80 ++++++++++++++++++++++++++-------------------------
1 file changed, 41 insertions(+), 39 deletions(-)
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 43cd89e..38eb17d 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -399,13 +399,13 @@ static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen,
return kernel_sendmsg(sock, &msg, NULL, 0, 0);
}
-static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy)
+static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy, int *sent_p)
{
ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
int offset, size_t size, int flags);
struct page **ppage;
unsigned int remainder;
- int err, sent = 0;
+ int err;
remainder = xdr->page_len - base;
base += xdr->page_base;
@@ -424,15 +424,15 @@ static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned i
err = do_sendpage(sock, *ppage, base, len, flags);
if (remainder == 0 || err != len)
break;
- sent += err;
+ *sent_p += err;
ppage++;
base = 0;
}
- if (sent == 0)
- return err;
- if (err > 0)
- sent += err;
- return sent;
+ if (err > 0) {
+ *sent_p += err;
+ err = 0;
+ }
+ return err;
}
/**
@@ -445,10 +445,11 @@ static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned i
* @zerocopy: true if it is safe to use sendpage()
*
*/
-static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy)
+static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy, int *sent_p)
{
unsigned int remainder = xdr->len - base;
- int err, sent = 0;
+ int err = 0;
+ int sent = 0;
if (unlikely(!sock))
return -ENOTSOCK;
@@ -465,7 +466,7 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen,
err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
if (remainder == 0 || err != len)
goto out;
- sent += err;
+ *sent_p += err;
base = 0;
} else
base -= xdr->head[0].iov_len;
@@ -473,23 +474,23 @@ static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen,
if (base < xdr->page_len) {
unsigned int len = xdr->page_len - base;
remainder -= len;
- err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy);
- if (remainder == 0 || err != len)
+ err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy, &sent);
+ *sent_p += sent;
+ if (remainder == 0 || sent != len)
goto out;
- sent += err;
base = 0;
} else
base -= xdr->page_len;
if (base >= xdr->tail[0].iov_len)
- return sent;
+ return 0;
err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
out:
- if (sent == 0)
- return err;
- if (err > 0)
- sent += err;
- return sent;
+ if (err > 0) {
+ *sent_p += err;
+ err = 0;
+ }
+ return err;
}
static void xs_nospace_callback(struct rpc_task *task)
@@ -573,19 +574,20 @@ static int xs_local_send_request(struct rpc_task *task)
container_of(xprt, struct sock_xprt, xprt);
struct xdr_buf *xdr = &req->rq_snd_buf;
int status;
+ int sent = 0;
xs_encode_stream_record_marker(&req->rq_snd_buf);
xs_pktdump("packet data:",
req->rq_svec->iov_base, req->rq_svec->iov_len);
- status = xs_sendpages(transport->sock, NULL, 0,
- xdr, req->rq_bytes_sent, true);
+ status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,
+ true, &sent);
dprintk("RPC: %s(%u) = %d\n",
__func__, xdr->len - req->rq_bytes_sent, status);
- if (likely(status >= 0)) {
- req->rq_bytes_sent += status;
- req->rq_xmit_bytes_sent += status;
+ if (likely(sent > 0) || status == 0) {
+ req->rq_bytes_sent += sent;
+ req->rq_xmit_bytes_sent += sent;
if (likely(req->rq_bytes_sent >= req->rq_slen)) {
req->rq_bytes_sent = 0;
return 0;
@@ -626,6 +628,7 @@ static int xs_udp_send_request(struct rpc_task *task)
struct rpc_xprt *xprt = req->rq_xprt;
struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
struct xdr_buf *xdr = &req->rq_snd_buf;
+ int sent = 0;
int status;
xs_pktdump("packet data:",
@@ -634,17 +637,15 @@ static int xs_udp_send_request(struct rpc_task *task)
if (!xprt_bound(xprt))
return -ENOTCONN;
- status = xs_sendpages(transport->sock,
- xs_addr(xprt),
- xprt->addrlen, xdr,
- req->rq_bytes_sent, true);
+ status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
+ xdr, req->rq_bytes_sent, true, &sent);
dprintk("RPC: xs_udp_send_request(%u) = %d\n",
xdr->len - req->rq_bytes_sent, status);
- if (status >= 0) {
- req->rq_xmit_bytes_sent += status;
- if (status >= req->rq_slen)
+ if (sent > 0 || status == 0) {
+ req->rq_xmit_bytes_sent += sent;
+ if (sent >= req->rq_slen)
return 0;
/* Still some bytes left; set up for a retry later. */
status = -EAGAIN;
@@ -713,6 +714,7 @@ static int xs_tcp_send_request(struct rpc_task *task)
struct xdr_buf *xdr = &req->rq_snd_buf;
bool zerocopy = true;
int status;
+ int sent = 0;
xs_encode_stream_record_marker(&req->rq_snd_buf);
@@ -730,26 +732,26 @@ static int xs_tcp_send_request(struct rpc_task *task)
* to cope with writespace callbacks arriving _after_ we have
* called sendmsg(). */
while (1) {
- status = xs_sendpages(transport->sock,
- NULL, 0, xdr, req->rq_bytes_sent,
- zerocopy);
+ sent = 0;
+ status = xs_sendpages(transport->sock, NULL, 0, xdr,
+ req->rq_bytes_sent, zerocopy, &sent);
dprintk("RPC: xs_tcp_send_request(%u) = %d\n",
xdr->len - req->rq_bytes_sent, status);
- if (unlikely(status < 0))
+ if (unlikely(sent == 0 && status < 0))
break;
/* If we've sent the entire packet, immediately
* reset the count of bytes sent. */
- req->rq_bytes_sent += status;
- req->rq_xmit_bytes_sent += status;
+ req->rq_bytes_sent += sent;
+ req->rq_xmit_bytes_sent += sent;
if (likely(req->rq_bytes_sent >= req->rq_slen)) {
req->rq_bytes_sent = 0;
return 0;
}
- if (status != 0)
+ if (sent != 0)
continue;
status = -EAGAIN;
break;
--
1.8.2.rc2
--
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