[PATCH] knfsd: Avoid excess stack usage in svc_tcp_recvfrom

..  by allocating the array of 'kvec' in 'struct svc_rqst'.

As we plan to increase RPCSVC_MAXPAGES from 8 upto 256, we can no longer
allocate an array of this size on the stack.  So we allocate it in 'struct
svc_rqst'.

However svc_rqst contains (indirectly) an array of the same type and size
(actually several, but they are in a union).  So rather than waste space, we
move those arrays out of the separately allocated union and into svc_rqst to
share with the kvec moved out of svc_tcp_recvfrom (various arrays are used at
different times, so there is no conflict).

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 25096d53667a..1d512337ccd9 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -955,7 +955,7 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp)
         struct svc_sock *svsk = rqstp->rq_sock;
         struct svc_serv *serv = svsk->sk_server;
         int             len;
-        struct kvec vec[RPCSVC_MAXPAGES];
+        struct kvec *vec;
         int pnum, vlen;
 
         dprintk("svc: tcp_recv %p data %d conn %d close %d\n",
@@ -1053,6 +1053,7 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp)
         len = svsk->sk_reclen;
         set_bit(SK_DATA, &svsk->sk_flags);
 
+        vec = rqstp->rq_vec;
         vec[0] = rqstp->rq_arg.head[0];
         vlen = PAGE_SIZE;
         pnum = 1;