On Tue, Jul 15, 2008 at 02:48:11PM -0400, J. Bruce Fields wrote:
> From: Jeff Layton <jlayton@xxxxxxxxxx>
>
> nlmsvc_testlock calls nlmsvc_lookup_host to find a nlm_host struct. The
> callers of this functions, however, call nlmsvc_retrieve_args or
> nlm4svc_retrieve_args, which also return a nlm_host struct.
>
> Change nlmsvc_testlock to take a host arg instead of calling
> nlmsvc_lookup_host itself and change the callers to pass a pointer to
> the nlm_host they've already found.
>
> We take a reference to host in the place where nlmsvc_testlock()
> previous did a new lookup, so the reference counting is unchanged from
> before.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
> ---
> fs/lockd/svc4proc.c | 2 +-
> fs/lockd/svclock.c | 12 +++---------
> fs/lockd/svcproc.c | 2 +-
> include/linux/lockd/lockd.h | 3 ++-
> 4 files changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
> index 006a832..8cfb9da 100644
> --- a/fs/lockd/svc4proc.c
> +++ b/fs/lockd/svc4proc.c
> @@ -99,7 +99,7 @@ nlm4svc_proc_test(struct svc_rqst *rqstp, struct nlm_args *argp,
> return resp->status == nlm_drop_reply ? rpc_drop_reply :rpc_success;
>
> /* Now check for conflicting locks */
> - resp->status = nlmsvc_testlock(rqstp, file, &argp->lock, &resp->lock, &resp->cookie);
> + resp->status = nlmsvc_testlock(rqstp, file, host, &argp->lock, &resp->lock, &resp->cookie);
> if (resp->status == nlm_drop_reply)
> rc = rpc_drop_reply;
> else
> diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
> index 81aca85..f40afb3 100644
> --- a/fs/lockd/svclock.c
> +++ b/fs/lockd/svclock.c
> @@ -460,8 +460,8 @@ out:
> */
> __be32
> nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
> - struct nlm_lock *lock, struct nlm_lock *conflock,
> - struct nlm_cookie *cookie)
> + struct nlm_host *host, struct nlm_lock *lock,
> + struct nlm_lock *conflock, struct nlm_cookie *cookie)
> {
> struct nlm_block *block = NULL;
> int error;
> @@ -479,16 +479,10 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
>
> if (block == NULL) {
> struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
> - struct nlm_host *host;
>
> if (conf == NULL)
> return nlm_granted;
> - /* Create host handle for callback */
> - host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len);
> - if (host == NULL) {
> - kfree(conf);
> - return nlm_lck_denied_nolocks;
> - }
> + nlm_get_host(host);
> block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
> if (block == NULL) {
> kfree(conf);
By the way, it'd seem clearer if nlmsvc_create_block() did the job of
taking whatever reference it needed on "host" itself.
Seems like you could do the same for nlm_alloc_host() as well.
--b.
commit cc8c1b0a6514c670b1ab568241210bbdbece7923
Author: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
Date: Tue Jul 15 15:05:45 2008 -0400
lockd: get host reference in nlmsvc_create_block() instead of callers
As it is it looks like there's an obvious reference count leak until you
track down the definition of nlm_alloc_host() and see that it's
guaranteed to consume a reference, success or failure.
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxxxxxx>
diff --git a/fs/lockd/svclock.c b/fs/lockd/svclock.c
index 92c49d7..80d4f2e 100644
--- a/fs/lockd/svclock.c
+++ b/fs/lockd/svclock.c
@@ -180,6 +180,7 @@ nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
struct nlm_block *block;
struct nlm_rqst *call = NULL;
+ nlm_get_host(host);
call = nlm_alloc_call(host);
if (call == NULL)
return NULL;
@@ -380,8 +381,7 @@ nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
*/
block = nlmsvc_lookup_block(file, lock);
if (block == NULL) {
- block = nlmsvc_create_block(rqstp, nlm_get_host(host), file,
- lock, cookie);
+ block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
ret = nlm_lck_denied_nolocks;
if (block == NULL)
goto out;
@@ -476,7 +476,6 @@ nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
if (conf == NULL)
return nlm_granted;
- nlm_get_host(host);
block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
if (block == NULL) {
kfree(conf);
--
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