[PATCH 1/4] io_uring: Always REQ_F_FREE_SQE for allocated sqe

Pavel Begunkov
2019-11-19T20:33:19Z

Always mark requests with allocated sqe and deallocate it in
__io_free_req(). It's easier to follow and doesn't add edge cases.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 49 ++++++++++++++++++++++---------------------------
1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 09a96516f690..ca3c5e979918 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -829,6 +829,8 @@ static void __io_free_req(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;

+ if (req->flags & REQ_F_FREE_SQE)
+ kfree(req->submit.sqe);
if (req->file && !(req->flags & REQ_F_FIXED_FILE))
fput(req->file);
if (req->flags & REQ_F_INFLIGHT) {
@@ -924,16 +926,11 @@ static void io_fail_links(struct io_kiocb *req)
spin_lock_irqsave(&ctx->completion_lock, flags);

while (!list_empty(&req->link_list)) {
- const struct io_uring_sqe *sqe_to_free = NULL;
-
link = list_first_entry(&req->link_list, struct io_kiocb, list);
list_del_init(&link->list);

trace_io_uring_fail_link(req, link);

- if (link->flags & REQ_F_FREE_SQE)
- sqe_to_free = link->submit.sqe;
-
if ((req->flags & REQ_F_LINK_TIMEOUT) &&
link->submit.sqe->opcode == IORING_OP_LINK_TIMEOUT) {
io_link_cancel_timeout(link);
@@ -941,7 +938,6 @@ static void io_fail_links(struct io_kiocb *req)
io_cqring_fill_event(link, -ECANCELED);
__io_double_put_req(link);
}
- kfree(sqe_to_free);
}

io_commit_cqring(ctx);
@@ -1083,7 +1079,8 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
* completions for those, only batch free for fixed
* file and non-linked commands.
*/
- if (((req->flags & (REQ_F_FIXED_FILE|REQ_F_LINK)) ==
+ if (((req->flags &
+ (REQ_F_FIXED_FILE|REQ_F_LINK|REQ_F_FREE_SQE)) ==
REQ_F_FIXED_FILE) && !io_is_fallback_req(req)) {
reqs[to_free++] = req;
if (to_free == ARRAY_SIZE(reqs))
@@ -2566,6 +2563,7 @@ static int io_req_defer(struct io_kiocb *req)
}

memcpy(sqe_copy, sqe, sizeof(*sqe_copy));
+ req->flags |= REQ_F_FREE_SQE;
req->submit.sqe = sqe_copy;

trace_io_uring_defer(ctx, req, false);
@@ -2660,7 +2658,6 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
struct io_wq_work *work = *workptr;
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct sqe_submit *s = &req->submit;
- const struct io_uring_sqe *sqe = s->sqe;
struct io_kiocb *nxt = NULL;
int ret = 0;

@@ -2696,9 +2693,6 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
io_put_req(req);
}

- /* async context always use a copy of the sqe */
- kfree(sqe);
-
/* if a dependent link is ready, pass it back */
if (!ret && nxt) {
struct io_kiocb *link;
@@ -2896,23 +2890,24 @@ static void __io_queue_sqe(struct io_kiocb *req)
struct io_uring_sqe *sqe_copy;

sqe_copy = kmemdup(s->sqe, sizeof(*sqe_copy), GFP_KERNEL);
- if (sqe_copy) {
- s->sqe = sqe_copy;
- if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) {
- ret = io_grab_files(req);
- if (ret) {
- kfree(sqe_copy);
- goto err;
- }
- }
+ if (!sqe_copy)
+ goto err;

- /*
- * Queued up for async execution, worker will release
- * submit reference when the iocb is actually submitted.
- */
- io_queue_async_work(req);
- return;
+ s->sqe = sqe_copy;
+ req->flags |= REQ_F_FREE_SQE;
+
+ if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) {
+ ret = io_grab_files(req);
+ if (ret)
+ goto err;
}
+
+ /*
+ * Queued up for async execution, worker will release
+ * submit reference when the iocb is actually submitted.
+ */
+ io_queue_async_work(req);
+ return;
}

err:
@@ -3003,7 +2998,6 @@ static void io_queue_link_head(struct io_kiocb *req, struct io_kiocb *shadow)
static void io_submit_sqe(struct io_kiocb *req, struct io_submit_state *state,
struct io_kiocb **link)
{
- struct io_uring_sqe *sqe_copy;
struct sqe_submit *s = &req->submit;
struct io_ring_ctx *ctx = req->ctx;
int ret;
@@ -3033,6 +3027,7 @@ static void io_submit_sqe(struct io_kiocb *req, struct io_submit_state *state,
*/
if (*link) {
struct io_kiocb *prev = *link;
+ struct io_uring_sqe *sqe_copy;

if (READ_ONCE(s->sqe->opcode) == IORING_OP_LINK_TIMEOUT) {
ret = io_timeout_setup(req);
--
2.24.0