Move the code that checks for available write space on the socket,
into a new transport function. This will allow transports flexibility
when determining if enough space/memory is available to process
the reply. The role of this function for RDMA is to avoid stalling
an knfsd thread when SQ space is not available.
Signed-off-by: Greg Banks <[EMAIL PROTECTED]>
Signed-off-by: Peter Leckie <[EMAIL PROTECTED]>
Signed-off-by: Tom Tucker <[EMAIL PROTECTED]>
---
include/linux/sunrpc/svcsock.h | 4 ++
net/sunrpc/svcsock.c | 75 ++++++++++++++++++++++++++--------------
2 files changed, 52 insertions(+), 27 deletions(-)
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 1da42c2..3faa95c 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -31,6 +31,10 @@ struct svc_xprt {
* Prepare any transport-specific RPC header.
*/
int (*xpt_prep_reply_hdr)(struct svc_rqst *);
+ /*
+ * Return 1 if sufficient space to write reply to network.
+ */
+ int (*xpt_has_wspace)(struct svc_sock *);
};
/*
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index ca473ee..b16dad4 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -205,22 +205,6 @@ svc_release_skb(struct svc_rqst *rqstp)
}
/*
- * Any space to write?
- */
-static inline unsigned long
-svc_sock_wspace(struct svc_sock *svsk)
-{
- int wspace;
-
- if (svsk->sk_sock->type == SOCK_STREAM)
- wspace = sk_stream_wspace(svsk->sk_sk);
- else
- wspace = sock_wspace(svsk->sk_sk);
-
- return wspace;
-}
-
-/*
* Queue up a socket with data pending. If there are idle nfsd
* processes, wake 'em up.
*
@@ -269,21 +253,13 @@ svc_sock_enqueue(struct svc_sock *svsk)
BUG_ON(svsk->sk_pool != NULL);
svsk->sk_pool = pool;
- set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
- if (((atomic_read(&svsk->sk_reserved) + serv->sv_max_mesg)*2
- > svc_sock_wspace(svsk))
- && !test_bit(SK_CLOSE, &svsk->sk_flags)
- && !test_bit(SK_CONN, &svsk->sk_flags)) {
- /* Don't enqueue while not enough space for reply */
- dprintk("svc: socket %p no space, %d*2 > %ld, not enqueued\n",
- svsk->sk_sk,
atomic_read(&svsk->sk_reserved)+serv->sv_max_mesg,
- svc_sock_wspace(svsk));
+ if (!test_bit(SK_CLOSE, &svsk->sk_flags)
+ && !test_bit(SK_CONN, &svsk->sk_flags)
+ && !svsk->sk_xprt->xpt_has_wspace(svsk)) {
svsk->sk_pool = NULL;
clear_bit(SK_BUSY, &svsk->sk_flags);
goto out_unlock;
}
- clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
-
if (!list_empty(&pool->sp_threads)) {
rqstp = list_entry(pool->sp_threads.next,
@@ -882,12 +858,45 @@ svc_udp_sendto(struct svc_rqst *rqstp)
return error;
}
+/**
+ * svc_sock_has_write_space - Checks if there is enough space
+ * to send the reply on the socket.
+ * @svsk: the svc_sock to write on
+ * @wspace: the number of bytes available for writing
+ */
+static int svc_sock_has_write_space(struct svc_sock *svsk, int wspace)
+{
+ struct svc_serv *serv = svsk->sk_server;
+ int required = atomic_read(&svsk->sk_reserved) + serv->sv_max_mesg;
+
+ if (required*2 > wspace) {
+ /* Don't enqueue while not enough space for reply */
+ dprintk("svc: socket %p no space, %d*2 > %d, not enqueued\n",
+ svsk->sk_sk, required, wspace);
+ return 0;
+ }
+ clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+ return 1;
+}
+
+static int
+svc_udp_has_wspace(struct svc_sock *svsk)
+{
+ /*
+ * Set the SOCK_NOSPACE flag before checking the available
+ * sock space.
+ */
+ set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+ return svc_sock_has_write_space(svsk, sock_wspace(svsk->sk_sk));
+}
+
static const struct svc_xprt svc_udp_xprt = {
.xpt_name = "udp",
.xpt_recvfrom = svc_udp_recvfrom,
.xpt_sendto = svc_udp_sendto,
.xpt_detach = svc_sock_detach,
.xpt_free = svc_sock_free,
+ .xpt_has_wspace = svc_udp_has_wspace,
};
static void
@@ -1340,6 +1349,17 @@ svc_tcp_prep_reply_hdr(struct svc_rqst *
return 0;
}
+static int
+svc_tcp_has_wspace(struct svc_sock *svsk)
+{
+ /*
+ * Set the SOCK_NOSPACE flag before checking the available
+ * sock space.
+ */
+ set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+ return svc_sock_has_write_space(svsk, sk_stream_wspace(svsk->sk_sk));
+}
+
static const struct svc_xprt svc_tcp_xprt = {
.xpt_name = "tcp",
.xpt_recvfrom = svc_tcp_recvfrom,
@@ -1347,6 +1367,7 @@ static const struct svc_xprt svc_tcp_xpr
.xpt_detach = svc_sock_detach,
.xpt_free = svc_sock_free,
.xpt_prep_reply_hdr = svc_tcp_prep_reply_hdr,
+ .xpt_has_wspace = svc_tcp_has_wspace,
};
static void
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