This is a note to let you know that I've just added the patch titled
NFSD: narrow nfsd_mutex protection in nfsd thread
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd-narrow-nfsd_mutex-protection-in-nfsd-thread.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 49f52c73fa67e8e823291c3ff3f600108bf659b9
Author: NeilBrown <neilb@xxxxxxx>
Date: Mon Nov 29 15:51:25 2021 +1100
NFSD: narrow nfsd_mutex protection in nfsd thread
[ Upstream commit 9d3792aefdcda71d20c2b1ecc589c17ae71eb523 ]
There is nothing happening in the start of nfsd() that requires
protection by the mutex, so don't take it until shutting down the thread
- which does still require protection - but only for nfsd_put().
Signed-off-by: NeilBrown <neilb@xxxxxxx>
[ cel: address merge conflict with fd2468fa1301 ]
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 16884a90e1ab0..eb8cc4d914fee 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -932,9 +932,6 @@ nfsd(void *vrqstp)
struct nfsd_net *nn = net_generic(net, nfsd_net_id);
int err;
- /* Lock module and set up kernel thread */
- mutex_lock(&nfsd_mutex);
-
/* At this point, the thread shares current->fs
* with the init process. We need to create files with the
* umask as defined by the client instead of init's umask. */
@@ -954,7 +951,6 @@ nfsd(void *vrqstp)
allow_signal(SIGINT);
allow_signal(SIGQUIT);
- mutex_unlock(&nfsd_mutex);
atomic_inc(&nfsdstats.th_cnt);
set_freezable();
@@ -983,7 +979,6 @@ nfsd(void *vrqstp)
flush_signals(current);
atomic_dec(&nfsdstats.th_cnt);
- mutex_lock(&nfsd_mutex);
out:
/* Take an extra ref so that the svc_put in svc_exit_thread()
@@ -995,10 +990,11 @@ nfsd(void *vrqstp)
svc_exit_thread(rqstp);
/* Now if needed we call svc_destroy in appropriate context */
+ mutex_lock(&nfsd_mutex);
nfsd_put(net);
+ mutex_unlock(&nfsd_mutex);
/* Release module */
- mutex_unlock(&nfsd_mutex);
module_put_and_kthread_exit(0);
return 0;
}
