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authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-14 19:43:27 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-14 19:43:27 -0500
commita311c480384c5aa9aaae195b89c3ec89c3b66379 (patch)
tree9e3f141bb7649278e0fe30e68d965f2243c32bb9
parent05064084e82d057f8d74590c51581650e060fbb8 (diff)
parentfa88b6f8803c87c4ced5aac11261ced7cedaa05e (diff)
Merge git://git.kvack.org/~bcrl/aio-next
Pull aio fix and cleanups from Ben LaHaise: "This consists of a couple of code cleanups plus a minor bug fix" * git://git.kvack.org/~bcrl/aio-next: aio: cleanup: flatten kill_ioctx() aio: report error from io_destroy() when threads race in io_destroy() fs/aio.c: Remove ctx parameter in kiocb_cancel
-rw-r--r--fs/aio.c70
1 files changed, 36 insertions, 34 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 56b28607c32d..4f078c054b41 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -477,7 +477,7 @@ void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel)
}
EXPORT_SYMBOL(kiocb_set_cancel_fn);
-static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb)
+static int kiocb_cancel(struct kiocb *kiocb)
{
kiocb_cancel_fn *old, *cancel;
@@ -538,7 +538,7 @@ static void free_ioctx_users(struct percpu_ref *ref)
struct kiocb, ki_list);
list_del_init(&req->ki_list);
- kiocb_cancel(ctx, req);
+ kiocb_cancel(req);
}
spin_unlock_irq(&ctx->ctx_lock);
@@ -727,42 +727,42 @@ err:
* when the processes owning a context have all exited to encourage
* the rapid destruction of the kioctx.
*/
-static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
+static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
struct completion *requests_done)
{
- if (!atomic_xchg(&ctx->dead, 1)) {
- struct kioctx_table *table;
+ struct kioctx_table *table;
- spin_lock(&mm->ioctx_lock);
- rcu_read_lock();
- table = rcu_dereference(mm->ioctx_table);
+ if (atomic_xchg(&ctx->dead, 1))
+ return -EINVAL;
- WARN_ON(ctx != table->table[ctx->id]);
- table->table[ctx->id] = NULL;
- rcu_read_unlock();
- spin_unlock(&mm->ioctx_lock);
- /* percpu_ref_kill() will do the necessary call_rcu() */
- wake_up_all(&ctx->wait);
+ spin_lock(&mm->ioctx_lock);
+ rcu_read_lock();
+ table = rcu_dereference(mm->ioctx_table);
- /*
- * It'd be more correct to do this in free_ioctx(), after all
- * the outstanding kiocbs have finished - but by then io_destroy
- * has already returned, so io_setup() could potentially return
- * -EAGAIN with no ioctxs actually in use (as far as userspace
- * could tell).
- */
- aio_nr_sub(ctx->max_reqs);
+ WARN_ON(ctx != table->table[ctx->id]);
+ table->table[ctx->id] = NULL;
+ rcu_read_unlock();
+ spin_unlock(&mm->ioctx_lock);
- if (ctx->mmap_size)
- vm_munmap(ctx->mmap_base, ctx->mmap_size);
+ /* percpu_ref_kill() will do the necessary call_rcu() */
+ wake_up_all(&ctx->wait);
- ctx->requests_done = requests_done;
- percpu_ref_kill(&ctx->users);
- } else {
- if (requests_done)
- complete(requests_done);
- }
+ /*
+ * It'd be more correct to do this in free_ioctx(), after all
+ * the outstanding kiocbs have finished - but by then io_destroy
+ * has already returned, so io_setup() could potentially return
+ * -EAGAIN with no ioctxs actually in use (as far as userspace
+ * could tell).
+ */
+ aio_nr_sub(ctx->max_reqs);
+
+ if (ctx->mmap_size)
+ vm_munmap(ctx->mmap_base, ctx->mmap_size);
+
+ ctx->requests_done = requests_done;
+ percpu_ref_kill(&ctx->users);
+ return 0;
}
/* wait_on_sync_kiocb:
@@ -1219,21 +1219,23 @@ SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
if (likely(NULL != ioctx)) {
struct completion requests_done =
COMPLETION_INITIALIZER_ONSTACK(requests_done);
+ int ret;
/* Pass requests_done to kill_ioctx() where it can be set
* in a thread-safe way. If we try to set it here then we have
* a race condition if two io_destroy() called simultaneously.
*/
- kill_ioctx(current->mm, ioctx, &requests_done);
+ ret = kill_ioctx(current->mm, ioctx, &requests_done);
percpu_ref_put(&ioctx->users);
/* Wait until all IO for the context are done. Otherwise kernel
* keep using user-space buffers even if user thinks the context
* is destroyed.
*/
- wait_for_completion(&requests_done);
+ if (!ret)
+ wait_for_completion(&requests_done);
- return 0;
+ return ret;
}
pr_debug("EINVAL: io_destroy: invalid context id\n");
return -EINVAL;
@@ -1595,7 +1597,7 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
kiocb = lookup_kiocb(ctx, iocb, key);
if (kiocb)
- ret = kiocb_cancel(ctx, kiocb);
+ ret = kiocb_cancel(kiocb);
else
ret = -EINVAL;

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