lockd: nlmclnt_reclaim(): avoid stack overflow

Even though nlmclnt_reclaim() is only one call into the stack frame,
928 bytes on the stack seems like a lot. Recode to dynamically
allocate the request structure once from within the reclaimer task,
then pass this pointer into nlmclnt_reclaim() for reuse on
subsequent calls.

smatch analysis:

fs/lockd/clntproc.c:620 nlmclnt_reclaim() warn: 'reqst' puts
 928 bytes on stack

Also remove redundant assignment of 0 after memset.

Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 54f9e6ce0430..b43114c4332a 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -615,17 +615,15 @@ out_unlock:
  * RECLAIM: Try to reclaim a lock
  */
 int
-nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
+nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
+                struct nlm_rqst *req)
 {
-        struct nlm_rqst reqst, *req;
         int             status;
 
-        req = &reqst;
         memset(req, 0, sizeof(*req));
         locks_init_lock(&req->a_args.lock.fl);
         locks_init_lock(&req->a_res.lock.fl);
         req->a_host  = host;
-        req->a_flags = 0;
 
         /* Set up the argument struct */
         nlmclnt_setlockargs(req, fl);