diff options
| author | NeilBrown <neil@brown.name> | 2025-05-09 10:46:43 +1000 |
|---|---|---|
| committer | Anna Schumaker <anna.schumaker@oracle.com> | 2025-05-28 17:17:14 -0400 |
| commit | c25a89770d1f216dcedfc2d25d56b604f62ce0bd (patch) | |
| tree | e5e0c6ebad5ceb43497f1a50ec9d99e84b8285eb /fs/nfs_common | |
| parent | 21fb44034695185f1dcbcb37354c842cabfe83c1 (diff) | |
nfs_localio: change nfsd_file_put_local() to take a pointer to __rcu pointer
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>
Diffstat (limited to 'fs/nfs_common')
| -rw-r--r-- | fs/nfs_common/nfslocalio.c | 24 |
1 files changed, 6 insertions, 18 deletions
diff --git a/fs/nfs_common/nfslocalio.c b/fs/nfs_common/nfslocalio.c index 1dd5a8cca064..05c7c16e37ab 100644 --- a/fs/nfs_common/nfslocalio.c +++ b/fs/nfs_common/nfslocalio.c @@ -170,9 +170,6 @@ static bool nfs_uuid_put(nfs_uuid_t *nfs_uuid) while ((nfl = list_first_entry_or_null(&nfs_uuid->files, struct nfs_file_localio, list)) != NULL) { - struct nfsd_file *ro_nf; - struct nfsd_file *rw_nf; - /* If nfs_uuid is already NULL, nfs_close_local_fh is * closing and we must wait, else we unlink and close. */ @@ -189,17 +186,14 @@ static bool nfs_uuid_put(nfs_uuid_t *nfs_uuid) continue; } - ro_nf = unrcu_pointer(xchg(&nfl->ro_file, NULL)); - rw_nf = unrcu_pointer(xchg(&nfl->rw_file, NULL)); - /* Remove nfl from nfs_uuid->files list */ list_del_init(&nfl->list); spin_unlock(&nfs_uuid->lock); - if (ro_nf) - nfs_to_nfsd_file_put_local(ro_nf); - if (rw_nf) - nfs_to_nfsd_file_put_local(rw_nf); + + nfs_to_nfsd_file_put_local(&nfl->ro_file); + nfs_to_nfsd_file_put_local(&nfl->rw_file); cond_resched(); + spin_lock(&nfs_uuid->lock); /* Now we can allow racing nfs_close_local_fh() to * skip the locking. @@ -303,8 +297,6 @@ EXPORT_SYMBOL_GPL(nfs_open_local_fh); void nfs_close_local_fh(struct nfs_file_localio *nfl) { - struct nfsd_file *ro_nf; - struct nfsd_file *rw_nf; nfs_uuid_t *nfs_uuid; rcu_read_lock(); @@ -337,12 +329,8 @@ void nfs_close_local_fh(struct nfs_file_localio *nfl) spin_unlock(&nfs_uuid->lock); rcu_read_unlock(); - ro_nf = unrcu_pointer(xchg(&nfl->ro_file, NULL)); - rw_nf = unrcu_pointer(xchg(&nfl->rw_file, NULL)); - if (ro_nf) - nfs_to_nfsd_file_put_local(ro_nf); - if (rw_nf) - nfs_to_nfsd_file_put_local(rw_nf); + nfs_to_nfsd_file_put_local(&nfl->ro_file); + nfs_to_nfsd_file_put_local(&nfl->rw_file); /* Remove nfl from nfs_uuid->files list and signal nfs_uuid_put() * that we are done. The moment we drop the spinlock the |