[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, 11 insertions, 11 deletions

diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c
index ad2fba3c54f8..ab6745e78d16 100644
--- a/fs/nfsd/nfsxdr.c
+++ b/fs/nfsd/nfsxdr.c
@@ -263,9 +263,9 @@ nfssvc_decode_readargs(struct svc_rqst *rqstp, u32 *p,
         v=0;
         while (len > 0) {
                 pn = rqstp->rq_resused++;
-                args->vec[v].iov_base = page_address(rqstp->rq_respages[pn]);
-                args->vec[v].iov_len = len < PAGE_SIZE?len:PAGE_SIZE;
-                len -= args->vec[v].iov_len;
+                rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_respages[pn]);
+                rqstp->rq_vec[v].iov_len = len < PAGE_SIZE?len:PAGE_SIZE;
+                len -= rqstp->rq_vec[v].iov_len;
                 v++;
         }
         args->vlen = v;
@@ -285,21 +285,21 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, u32 *p,
         args->offset = ntohl(*p++);     /* offset */
         p++;                            /* totalcount */
         len = args->len = ntohl(*p++);
-        args->vec[0].iov_base = (void*)p;
-        args->vec[0].iov_len = rqstp->rq_arg.head[0].iov_len -
+        rqstp->rq_vec[0].iov_base = (void*)p;
+        rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len -
                                 (((void*)p) - rqstp->rq_arg.head[0].iov_base);
         if (len > NFSSVC_MAXBLKSIZE)
                 len = NFSSVC_MAXBLKSIZE;
         v = 0;
-        while (len > args->vec[v].iov_len) {
-                len -= args->vec[v].iov_len;
+        while (len > rqstp->rq_vec[v].iov_len) {
+                len -= rqstp->rq_vec[v].iov_len;
                 v++;
-                args->vec[v].iov_base = page_address(rqstp->rq_pages[v]);
-                args->vec[v].iov_len = PAGE_SIZE;
+                rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_pages[v]);
+                rqstp->rq_vec[v].iov_len = PAGE_SIZE;
         }
-        args->vec[v].iov_len = len;
+        rqstp->rq_vec[v].iov_len = len;
         args->vlen = v+1;
-        return args->vec[0].iov_len > 0;
+        return rqstp->rq_vec[0].iov_len > 0;
 }
 
 int