diff options
author | Jakub Kicinski <kuba@kernel.org> | 2022-07-28 18:21:16 -0700 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2022-07-28 18:21:16 -0700 |
commit | 272ac32f566e3f925b20c231a2b30f6893aa258a (patch) | |
tree | c7c04a13d89349f0d007914904347df79438f3fa /kernel/watch_queue.c | |
parent | 623cd87006983935de6c2ad8e2d50e68f1b7d6e7 (diff) | |
parent | 33ea1340bafe1f394e5bf96fceef73e9771d066b (diff) | |
download | linux-stable-272ac32f566e3f925b20c231a2b30f6893aa258a.tar.gz |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'kernel/watch_queue.c')
-rw-r--r-- | kernel/watch_queue.c | 58 |
1 files changed, 36 insertions, 22 deletions
diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c index bb9962b33f95..59ddb00d6944 100644 --- a/kernel/watch_queue.c +++ b/kernel/watch_queue.c @@ -454,6 +454,33 @@ void init_watch(struct watch *watch, struct watch_queue *wqueue) rcu_assign_pointer(watch->queue, wqueue); } +static int add_one_watch(struct watch *watch, struct watch_list *wlist, struct watch_queue *wqueue) +{ + const struct cred *cred; + struct watch *w; + + hlist_for_each_entry(w, &wlist->watchers, list_node) { + struct watch_queue *wq = rcu_access_pointer(w->queue); + if (wqueue == wq && watch->id == w->id) + return -EBUSY; + } + + cred = current_cred(); + if (atomic_inc_return(&cred->user->nr_watches) > task_rlimit(current, RLIMIT_NOFILE)) { + atomic_dec(&cred->user->nr_watches); + return -EAGAIN; + } + + watch->cred = get_cred(cred); + rcu_assign_pointer(watch->watch_list, wlist); + + kref_get(&wqueue->usage); + kref_get(&watch->usage); + hlist_add_head(&watch->queue_node, &wqueue->watches); + hlist_add_head_rcu(&watch->list_node, &wlist->watchers); + return 0; +} + /** * add_watch_to_object - Add a watch on an object to a watch list * @watch: The watch to add @@ -468,34 +495,21 @@ void init_watch(struct watch *watch, struct watch_queue *wqueue) */ int add_watch_to_object(struct watch *watch, struct watch_list *wlist) { - struct watch_queue *wqueue = rcu_access_pointer(watch->queue); - struct watch *w; - - hlist_for_each_entry(w, &wlist->watchers, list_node) { - struct watch_queue *wq = rcu_access_pointer(w->queue); - if (wqueue == wq && watch->id == w->id) - return -EBUSY; - } - - watch->cred = get_current_cred(); - rcu_assign_pointer(watch->watch_list, wlist); + struct watch_queue *wqueue; + int ret = -ENOENT; - if (atomic_inc_return(&watch->cred->user->nr_watches) > - task_rlimit(current, RLIMIT_NOFILE)) { - atomic_dec(&watch->cred->user->nr_watches); - put_cred(watch->cred); - return -EAGAIN; - } + rcu_read_lock(); + wqueue = rcu_access_pointer(watch->queue); if (lock_wqueue(wqueue)) { - kref_get(&wqueue->usage); - kref_get(&watch->usage); - hlist_add_head(&watch->queue_node, &wqueue->watches); + spin_lock(&wlist->lock); + ret = add_one_watch(watch, wlist, wqueue); + spin_unlock(&wlist->lock); unlock_wqueue(wqueue); } - hlist_add_head(&watch->list_node, &wlist->watchers); - return 0; + rcu_read_unlock(); + return ret; } EXPORT_SYMBOL(add_watch_to_object); |