[PATCH 09/11] nfs: add memory barrier before calling wake_up_var on cl_state

NeilBrown
2024-12-06T02:19:52Z

After setting NFS4CLNT_RUN_MANAGER we need a full memory barrier before
it is safe to call wake_up_var(). As that setting is "atomic" it is
sufficient to use smp_mb__after_atomic().

Signed-off-by: NeilBrown <neilb@suse.de>
---
fs/nfs/nfs4proc.c | 1 +
fs/nfs/nfs4state.c | 1 +
2 files changed, 2 insertions(+)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 405f17e6e0b4..37c8aa1f3e1b 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -10847,6 +10847,7 @@ static void nfs4_disable_swap(struct inode *inode)

set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);
clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);
+ smp_mb__after_atomic();
wake_up_var(&clp->cl_state);
}

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 556b521f17eb..189d7b57cb74 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1207,6 +1207,7 @@ void nfs4_schedule_state_manager(struct nfs_client *clp)
swapon = !test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE,
&clp->cl_state);
if (!swapon) {
+ smp_mb__after_atomic();
wake_up_var(&clp->cl_state);
return;
}
--
2.47.0