io_uring/cmd: don't expose entire cmd async data

io_uring needs private bits in cmd's ->async_data, and they should never
be exposed to drivers as it'd certainly be abused. Leave struct
io_uring_cmd_data for the drivers but wrap it into a structure. It's a
prep patch and doesn't do anything useful yet.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20250319061251.21452-3-sidong.yang@furiosa.ai
Signed-off-by: Jens Axboe <axboe@kernel.dk>
pull/1188/head
Pavel Begunkov 2025-03-19 06:12:48 +00:00 committed by Jens Axboe
parent 575e7b0629
commit 5f14404bfa
4 changed files with 19 additions and 9 deletions

View File

@ -335,7 +335,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
sizeof(struct io_async_rw),
offsetof(struct io_async_rw, clear));
ret |= io_alloc_cache_init(&ctx->cmd_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct io_uring_cmd_data), 0);
sizeof(struct io_async_cmd), 0);
spin_lock_init(&ctx->msg_lock);
ret |= io_alloc_cache_init(&ctx->msg_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct io_kiocb), 0);

View File

@ -416,7 +416,7 @@ const struct io_issue_def io_issue_defs[] = {
.plug = 1,
.iopoll = 1,
.iopoll_queue = 1,
.async_size = sizeof(struct io_uring_cmd_data),
.async_size = sizeof(struct io_async_cmd),
.prep = io_uring_cmd_prep,
.issue = io_uring_cmd,
},

View File

@ -19,7 +19,8 @@
static void io_req_uring_cleanup(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
struct io_uring_cmd_data *cache = req->async_data;
struct io_async_cmd *ac = req->async_data;
struct io_uring_cmd_data *cache = &ac->data;
if (cache->op_data) {
kfree(cache->op_data);
@ -169,12 +170,15 @@ static int io_uring_cmd_prep_setup(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
struct io_uring_cmd_data *cache;
struct io_async_cmd *ac;
cache = io_uring_alloc_async_data(&req->ctx->cmd_cache, req);
if (!cache)
/* see io_uring_cmd_get_async_data() */
BUILD_BUG_ON(offsetof(struct io_async_cmd, data) != 0);
ac = io_uring_alloc_async_data(&req->ctx->cmd_cache, req);
if (!ac)
return -ENOMEM;
cache->op_data = NULL;
ac->data.op_data = NULL;
/*
* Unconditionally cache the SQE for now - this is only needed for
@ -183,8 +187,8 @@ static int io_uring_cmd_prep_setup(struct io_kiocb *req,
* that it doesn't read in per-op data, play it safe and ensure that
* any SQE data is stable beyond prep. This can later get relaxed.
*/
memcpy(cache->sqes, sqe, uring_sqe_size(req->ctx));
ioucmd->sqe = cache->sqes;
memcpy(ac->data.sqes, sqe, uring_sqe_size(req->ctx));
ioucmd->sqe = ac->data.sqes;
return 0;
}

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@ -1,5 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/io_uring/cmd.h>
struct io_async_cmd {
struct io_uring_cmd_data data;
};
int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags);
int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);