diff options
| author | David Howells <dhowells@redhat.com> | 2019-05-13 17:14:32 +0200 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2019-05-16 23:23:21 +0200 |
| commit | f642404a0436a50912c218009ccc7856d48d784c (patch) | |
| tree | ddf39d1741f07866333581e66f1abc0e6709d453 /fs/afs/security.c | |
| parent | afs: Split afs_validate() so first part can be used under LOOKUP_RCU (diff) | |
| download | linux-f642404a0436a50912c218009ccc7856d48d784c.tar.xz linux-f642404a0436a50912c218009ccc7856d48d784c.zip | |
afs: Make vnode->cb_interest RCU safe
Use RCU-based freeing for afs_cb_interest struct objects and use RCU on
vnode->cb_interest. Use that change to allow afs_check_validity() to use
read_seqbegin_or_lock() instead of read_seqlock_excl().
This also requires the caller of afs_check_validity() to hold the RCU read
lock across the call.
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/afs/security.c')
| -rw-r--r-- | fs/afs/security.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/afs/security.c b/fs/afs/security.c index 857f09d09ee9..5d8ece98561e 100644 --- a/fs/afs/security.c +++ b/fs/afs/security.c @@ -146,7 +146,7 @@ void afs_cache_permit(struct afs_vnode *vnode, struct key *key, } if (afs_cb_is_broken(cb_break, vnode, - vnode->cb_interest)) { + rcu_dereference(vnode->cb_interest))) { changed = true; break; } @@ -176,7 +176,7 @@ void afs_cache_permit(struct afs_vnode *vnode, struct key *key, } } - if (afs_cb_is_broken(cb_break, vnode, vnode->cb_interest)) + if (afs_cb_is_broken(cb_break, vnode, rcu_dereference(vnode->cb_interest))) goto someone_else_changed_it; /* We need a ref on any permits list we want to copy as we'll have to @@ -253,14 +253,16 @@ found: kfree(new); + rcu_read_lock(); spin_lock(&vnode->lock); zap = rcu_access_pointer(vnode->permit_cache); - if (!afs_cb_is_broken(cb_break, vnode, vnode->cb_interest) && + if (!afs_cb_is_broken(cb_break, vnode, rcu_dereference(vnode->cb_interest)) && zap == permits) rcu_assign_pointer(vnode->permit_cache, replacement); else zap = replacement; spin_unlock(&vnode->lock); + rcu_read_unlock(); afs_put_permits(zap); out_put: afs_put_permits(permits); |