This function is not currently "generic" so remove the documenting
comment and rename it appropriately. Its internals are converted to
use bio_vecs for reading from the transport socket.
In existing typical sunrpc uses of bio_vecs, the bio_vec array is
allocated dynamically. Here, instead, an array of bio_vecs is added
to svc_rqst. The lifetime of this array can be greater than one call
to xpo_recvfrom():
- Multiple calls to xpo_recvfrom() might be needed to read an RPC
message completely.
- At some later point, rq_arg.bvecs will point to this array and it
will carry the received message into svc_process().
I also expect that a future optimization will remove either the
rq_vec or rq_pages array in favor of rq_bvec, thus conserving the
size of struct svc_rqst.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc.h | 1
net/sunrpc/svcsock.c | 109 +++++++++++++++++++++++++++-----------------
2 files changed, 69 insertions(+), 41 deletions(-)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index fd390894a584..05da19a0516d 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -254,6 +254,7 @@ struct svc_rqst {
struct page * *rq_page_end; /* one past the last page */
struct kvec rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
+ struct bio_vec rq_bvec[RPCSVC_MAXPAGES];
__be32 rq_xid; /* transmission id */
u32 rq_prog; /* program number */
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 5b2981a0711c..3e25511b800e 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -223,26 +223,62 @@ static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
return len;
}
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+static void svc_flush_bvec(const struct bio_vec *bvec, size_t size, size_t seek)
+{
+ struct bvec_iter bi = {
+ .bi_size = size,
+ };
+ struct bio_vec bv;
+
+ bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
+ for_each_bvec(bv, bvec, bi, bi)
+ flush_dcache_page(bv.bv_page);
+}
+#else
+static inline void svc_flush_bvec(const struct bio_vec *bvec, size_t size,
+ size_t seek)
+{
+}
+#endif
+
/*
- * Generic recvfrom routine.
+ * Read from @rqstp's transport socket. The incoming message fills whole
+ * pages in @rqstp's rq_pages array until the last page of the message
+ * has been received into a partial page.
*/
-static ssize_t svc_recvfrom(struct svc_rqst *rqstp, struct kvec *iov,
- unsigned int nr, size_t buflen, unsigned int base)
+static ssize_t svc_tcp_read_msg(struct svc_rqst *rqstp, size_t buflen,
+ size_t seek)
{
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
+ struct bio_vec *bvec = rqstp->rq_bvec;
struct msghdr msg = { NULL };
+ unsigned int i;
ssize_t len;
+ size_t t;
rqstp->rq_xprt_hlen = 0;
clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
- iov_iter_kvec(&msg.msg_iter, READ, iov, nr, buflen);
- if (base != 0) {
- iov_iter_advance(&msg.msg_iter, base);
- buflen -= base;
+
+ for (i = 0, t = 0; t < buflen; i++, t += PAGE_SIZE) {
+ bvec[i].bv_page = rqstp->rq_pages[i];
+ bvec[i].bv_len = PAGE_SIZE;
+ bvec[i].bv_offset = 0;
+ }
+ rqstp->rq_respages = &rqstp->rq_pages[i];
+ rqstp->rq_next_page = rqstp->rq_respages + 1;
+
+ iov_iter_bvec(&msg.msg_iter, READ, bvec, i, buflen);
+ if (seek) {
+ iov_iter_advance(&msg.msg_iter, seek);
+ buflen -= seek;
}
len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
+ if (len > 0)
+ svc_flush_bvec(bvec, len, seek);
+
/* If we read a full record, then assume there may be more
* data to read (stream based sockets only!)
*/
@@ -775,13 +811,14 @@ static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
return NULL;
}
-static unsigned int svc_tcp_restore_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
+static size_t svc_tcp_restore_pages(struct svc_sock *svsk,
+ struct svc_rqst *rqstp)
{
- unsigned int i, len, npages;
+ size_t len = svsk->sk_datalen;
+ unsigned int i, npages;
- if (svsk->sk_datalen == 0)
+ if (!len)
return 0;
- len = svsk->sk_datalen;
npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
for (i = 0; i < npages; i++) {
if (rqstp->rq_pages[i] != NULL)
@@ -917,20 +954,6 @@ static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
return -EAGAIN;
}
-static int copy_pages_to_kvecs(struct kvec *vec, struct page **pages, int len)
-{
- int i = 0;
- int t = 0;
-
- while (t < len) {
- vec[i].iov_base = page_address(pages[i]);
- vec[i].iov_len = PAGE_SIZE;
- i++;
- t += PAGE_SIZE;
- }
- return i;
-}
-
static void svc_tcp_fragment_received(struct svc_sock *svsk)
{
/* If we have more data, signal svc_xprt_enqueue() to try again */
@@ -938,20 +961,33 @@ static void svc_tcp_fragment_received(struct svc_sock *svsk)
svsk->sk_marker = xdr_zero;
}
-/*
- * Receive data from a TCP socket.
+/**
+ * svc_tcp_recvfrom - Receive data from a TCP socket
+ * @rqstp: request structure into which to receive an RPC Call
+ *
+ * Called in a loop when XPT_DATA has been set.
+ *
+ * Read the 4-byte stream record marker, then use the record length
+ * in that marker to set up exactly the resources needed to receive
+ * the next RPC message into @rqstp.
+ *
+ * Returns:
+ * On success, the number of bytes in a received RPC Call, or
+ * %0 if a complete RPC Call message was not ready to return
+ *
+ * The zero return case handles partial receives and callback Replies.
+ * The state of a partial receive is preserved in the svc_sock for
+ * the next call to svc_tcp_recvfrom.
*/
static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
{
struct svc_sock *svsk =
container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
struct svc_serv *serv = svsk->sk_xprt.xpt_server;
- int len;
- struct kvec *vec;
- unsigned int want, base;
+ size_t want, base;
+ ssize_t len;
__be32 *p;
__be32 calldir;
- int pnum;
clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
len = svc_tcp_read_marker(svsk, rqstp);
@@ -960,16 +996,7 @@ static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
base = svc_tcp_restore_pages(svsk, rqstp);
want = len - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
-
- vec = rqstp->rq_vec;
-
- pnum = copy_pages_to_kvecs(&vec[0], &rqstp->rq_pages[0], base + want);
-
- rqstp->rq_respages = &rqstp->rq_pages[pnum];
- rqstp->rq_next_page = rqstp->rq_respages + 1;
-
- /* Now receive data */
- len = svc_recvfrom(rqstp, vec, pnum, base + want, base);
+ len = svc_tcp_read_msg(rqstp, base + want, base);
if (len >= 0) {
trace_svcsock_tcp_recv(&svsk->sk_xprt, len);
svsk->sk_tcplen += len;
