io_uring: refactor io_alloc_req

Replace the main if of io_flush_cached_reqs() with inverted condition +
goto, so all the cases are handled in the same way. And also extract
io_preinit_req() to make it cleaner and easier to refer to.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1abcba1f7b55dc53bf1dbe95036e345ffb1d5b01.1628471125.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-08-09 13:04:08 +01:00 коммит произвёл Jens Axboe
Родитель 8724dd8c83
Коммит 864ea921b0
1 изменённых файлов: 33 добавлений и 33 удалений

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@ -1702,6 +1702,19 @@ static void io_req_complete_failed(struct io_kiocb *req, long res)
io_req_complete_post(req, res, 0);
}
/*
* Don't initialise the fields below on every allocation, but do that in
* advance and keep them valid across allocations.
*/
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
req->ctx = ctx;
req->link = NULL;
req->async_data = NULL;
/* not necessary, but safer to zero */
req->result = 0;
}
static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
struct io_comp_state *cs)
{
@ -1744,45 +1757,31 @@ static bool io_flush_cached_reqs(struct io_ring_ctx *ctx)
static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
{
struct io_submit_state *state = &ctx->submit_state;
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
int ret, i;
BUILD_BUG_ON(ARRAY_SIZE(state->reqs) < IO_REQ_ALLOC_BATCH);
if (!state->free_reqs) {
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
int ret, i;
if (likely(state->free_reqs || io_flush_cached_reqs(ctx)))
goto got_req;
if (io_flush_cached_reqs(ctx))
goto got_req;
ret = kmem_cache_alloc_bulk(req_cachep, gfp, IO_REQ_ALLOC_BATCH,
state->reqs);
ret = kmem_cache_alloc_bulk(req_cachep, gfp, IO_REQ_ALLOC_BATCH,
state->reqs);
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!state->reqs[0])
return NULL;
ret = 1;
}
/*
* Don't initialise the fields below on every allocation, but
* do that in advance and keep valid on free.
*/
for (i = 0; i < ret; i++) {
struct io_kiocb *req = state->reqs[i];
req->ctx = ctx;
req->link = NULL;
req->async_data = NULL;
/* not necessary, but safer to zero */
req->result = 0;
}
state->free_reqs = ret;
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!state->reqs[0])
return NULL;
ret = 1;
}
for (i = 0; i < ret; i++)
io_preinit_req(state->reqs[i], ctx);
state->free_reqs = ret;
got_req:
state->free_reqs--;
return state->reqs[state->free_reqs];
@ -6569,6 +6568,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
unsigned int sqe_flags;
int personality, ret = 0;
/* req is partially pre-initialised, see io_preinit_req() */
req->opcode = READ_ONCE(sqe->opcode);
/* same numerical values with corresponding REQ_F_*, safe to copy */
req->flags = sqe_flags = READ_ONCE(sqe->flags);