aboutsummaryrefslogtreecommitdiff
path: root/fs/aio.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-06 20:22:54 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2019-03-17 20:52:24 -0400
commitb53119f13a04879c3bf502828d99d13726639ead (patch)
tree6ada7dfb2a552754f28b7c883992b2417c4b4b3f /fs/aio.c
parent9e98c678c2d6ae3a17cb2de55d17f69dddaa231b (diff)
downloadlinux-stericsson-b53119f13a04879c3bf502828d99d13726639ead.tar.gz
pin iocb through aio.
aio_poll() is not the only case that needs file pinned; worse, while aio_read()/aio_write() can live without pinning iocb itself, the proof is rather brittle and can easily break on later changes. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c37
1 files changed, 21 insertions, 16 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 38b741aef0bf..07083fc0a24b 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1022,6 +1022,9 @@ static bool get_reqs_available(struct kioctx *ctx)
/* aio_get_req
* Allocate a slot for an aio request.
* Returns NULL if no requests are free.
+ *
+ * The refcount is initialized to 2 - one for the async op completion,
+ * one for the synchronous code that does this.
*/
static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
{
@@ -1034,7 +1037,7 @@ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
percpu_ref_get(&ctx->reqs);
req->ki_ctx = ctx;
INIT_LIST_HEAD(&req->ki_list);
- refcount_set(&req->ki_refcnt, 0);
+ refcount_set(&req->ki_refcnt, 2);
req->ki_eventfd = NULL;
return req;
}
@@ -1067,15 +1070,18 @@ out:
return ret;
}
+static inline void iocb_destroy(struct aio_kiocb *iocb)
+{
+ if (iocb->ki_filp)
+ fput(iocb->ki_filp);
+ percpu_ref_put(&iocb->ki_ctx->reqs);
+ kmem_cache_free(kiocb_cachep, iocb);
+}
+
static inline void iocb_put(struct aio_kiocb *iocb)
{
- if (refcount_read(&iocb->ki_refcnt) == 0 ||
- refcount_dec_and_test(&iocb->ki_refcnt)) {
- if (iocb->ki_filp)
- fput(iocb->ki_filp);
- percpu_ref_put(&iocb->ki_ctx->reqs);
- kmem_cache_free(kiocb_cachep, iocb);
- }
+ if (refcount_dec_and_test(&iocb->ki_refcnt))
+ iocb_destroy(iocb);
}
static void aio_fill_event(struct io_event *ev, struct aio_kiocb *iocb,
@@ -1749,9 +1755,6 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
INIT_LIST_HEAD(&req->wait.entry);
init_waitqueue_func_entry(&req->wait, aio_poll_wake);
- /* one for removal from waitqueue, one for this function */
- refcount_set(&aiocb->ki_refcnt, 2);
-
mask = vfs_poll(req->file, &apt.pt) & req->events;
if (unlikely(!req->head)) {
/* we did not manage to set up a waitqueue, done */
@@ -1782,7 +1785,6 @@ out:
if (mask)
aio_poll_complete(aiocb, mask);
- iocb_put(aiocb);
return 0;
}
@@ -1873,18 +1875,21 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,
break;
}
+ /* Done with the synchronous reference */
+ iocb_put(req);
+
/*
* If ret is 0, we'd either done aio_complete() ourselves or have
* arranged for that to be done asynchronously. Anything non-zero
* means that we need to destroy req ourselves.
*/
- if (ret)
- goto out_put_req;
- return 0;
+ if (!ret)
+ return 0;
+
out_put_req:
if (req->ki_eventfd)
eventfd_ctx_put(req->ki_eventfd);
- iocb_put(req);
+ iocb_destroy(req);
out_put_reqs_available:
put_reqs_available(ctx, 1);
return ret;