diff options
| author | NeilBrown <neil@brown.name> | 2025-05-09 10:46:43 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-19 15:40:25 +0200 |
| commit | 3f28e08941e340ecdea818323777a909c40f824c (patch) | |
| tree | d14858d2d0c7b74056e0355deeaa9b9ebdf939f3 /fs/nfs/localio.c | |
| parent | 0965a7f65808c2b940e53d5559e14476464554e3 (diff) | |
nfs_localio: change nfsd_file_put_local() to take a pointer to __rcu pointer
[ Upstream commit c25a89770d1f216dcedfc2d25d56b604f62ce0bd ]
Instead of calling xchg() and unrcu_pointer() before
nfsd_file_put_local(), we now pass pointer to the __rcu pointer and call
xchg() and unrcu_pointer() inside that function.
Where unrcu_pointer() is currently called the internals of "struct
nfsd_file" are not known and that causes older compilers such as gcc-8
to complain.
In some cases we have a __kernel (aka normal) pointer not an __rcu
pointer so we need to cast it to __rcu first. This is strictly a
weakening so no information is lost. Somewhat surprisingly, this cast
is accepted by gcc-8.
This has the pleasing result that the cmpxchg() which sets ro_file and
rw_file, and also the xchg() which clears them, are both now in the nfsd
code.
Reported-by: Pali Rohár <pali@kernel.org>
Reported-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Fixes: 86e00412254a ("nfs: cache all open LOCALIO nfsd_file(s) in client")
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/nfs/localio.c')
| -rw-r--r-- | fs/nfs/localio.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c index 030a54c8c9d8b..e6d36b3d3fc05 100644 --- a/fs/nfs/localio.c +++ b/fs/nfs/localio.c @@ -207,9 +207,16 @@ void nfs_local_probe_async(struct nfs_client *clp) } EXPORT_SYMBOL_GPL(nfs_local_probe_async); -static inline void nfs_local_file_put(struct nfsd_file *nf) +static inline void nfs_local_file_put(struct nfsd_file *localio) { - nfs_to_nfsd_file_put_local(nf); + /* nfs_to_nfsd_file_put_local() expects an __rcu pointer + * but we have a __kernel pointer. It is always safe + * to cast a __kernel pointer to an __rcu pointer + * because the cast only weakens what is known about the pointer. + */ + struct nfsd_file __rcu *nf = (struct nfsd_file __rcu*) localio; + + nfs_to_nfsd_file_put_local(&nf); } /* |