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| author | Oleg Nesterov <oleg@redhat.com> | 2015-08-21 19:42:55 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-10-06 20:25:26 +0200 |
| commit | 95b19f684c61ffc9b039e02c5d1113c2d8cd7105 (patch) | |
| tree | 5faf2eee589b2acb438a0881c2c3d80877f96bd5 /kernel/locking/percpu-rwsem.c | |
| parent | rcu_sync: Introduce rcu_sync_dtor() (diff) | |
| download | linux-95b19f684c61ffc9b039e02c5d1113c2d8cd7105.tar.xz linux-95b19f684c61ffc9b039e02c5d1113c2d8cd7105.zip | |
locking/percpu-rwsem: Make percpu_free_rwsem() after kzalloc() safe
This is the temporary ugly hack which will be reverted later. We only
need it to ensure that the next patch will not break "change sb_writers
to use percpu_rw_semaphore" patches routed via the VFS tree.
The alloc_super()->destroy_super() error path assumes that it is safe
to call percpu_free_rwsem() after kzalloc() without percpu_init_rwsem(),
so let's not disappoint it.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/locking/percpu-rwsem.c')
| -rw-r--r-- | kernel/locking/percpu-rwsem.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index e2621fbbcbd1..9529a30ec57b 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -26,6 +26,13 @@ EXPORT_SYMBOL_GPL(__percpu_init_rwsem); void percpu_free_rwsem(struct percpu_rw_semaphore *brw) { + /* + * XXX: temporary kludge. The error path in alloc_super() + * assumes that percpu_free_rwsem() is safe after kzalloc(). + */ + if (!brw->fast_read_ctr) + return; + free_percpu(brw->fast_read_ctr); brw->fast_read_ctr = NULL; /* catch use after free bugs */ } |