[PATCH] knfsd: svcrpc: gss: don't call svc_take_page unnecessarily

We're using svc_take_page here to get another page for the tail in case one
wasn't already allocated.  But there isn't always guaranteed to be another
page available.

Also fix a typo that made us check the tail buffer for space when we meant to
be checking the head buffer.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
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, 8 insertions, 6 deletions

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 4d7eb9e704da..d51e316c5821 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1122,18 +1122,20 @@ svcauth_gss_release(struct svc_rqst *rqstp)
                                         integ_len))
                         BUG();
                 if (resbuf->page_len == 0
-                        && resbuf->tail[0].iov_len + RPC_MAX_AUTH_SIZE
+                        && resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE
                                 < PAGE_SIZE) {
                         BUG_ON(resbuf->tail[0].iov_len);
                         /* Use head for everything */
                         resv = &resbuf->head[0];
                 } else if (resbuf->tail[0].iov_base == NULL) {
-                        /* copied from nfsd4_encode_read */
-                        svc_take_page(rqstp);
-                        resbuf->tail[0].iov_base = page_address(rqstp
-                                        ->rq_respages[rqstp->rq_resused-1]);
-                        rqstp->rq_restailpage = rqstp->rq_resused-1;
+                        if (resbuf->head[0].iov_len + RPC_MAX_AUTH_SIZE
+                                        > PAGE_SIZE)
+                                goto out_err;
+                        resbuf->tail[0].iov_base =
+                                resbuf->head[0].iov_base
+                                + resbuf->head[0].iov_len;
                         resbuf->tail[0].iov_len = 0;
+                        rqstp->rq_restailpage = 0;
                         resv = &resbuf->tail[0];
                 } else {
                         resv = &resbuf->tail[0];