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io_uring: cancelable uring_cmd

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uring_cmd may never complete, such as ublk, in which uring cmd isn't
completed until one new block request is coming from ublk block device.

Add cancelable uring_cmd to provide mechanism to driver for cancelling
pending commands in its own way.

Add API of io_uring_cmd_mark_cancelable() for driver to mark one command as
cancelable, then io_uring will cancel this command in
io_uring_cancel_generic(). ->uring_cmd() callback is reused for canceling
command in driver's way, then driver gets notified with the cancelling
from io_uring.

Add API of io_uring_cmd_get_task() to help driver cancel handler
deal with the canceling.

Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2023-09-28 20:43:25 +08:00 committed by Jens Axboe
parent 528ce67817
commit 93b8cc60c3
4 changed files with 101 additions and 0 deletions
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15
include/linux/io_uring.h
View File

@ -20,9 +20,13 @@ enum io_uring_cmd_flags {
IO_URING_F_SQE128 = (1 << 8),
IO_URING_F_CQE32 = (1 << 9),
IO_URING_F_IOPOLL = (1 << 10),
/* set when uring wants to cancel a previously issued command */
IO_URING_F_CANCEL = (1 << 11),
};
/* only top 8 bits of sqe->uring_cmd_flags for kernel internal use */
#define IORING_URING_CMD_CANCELABLE (1U << 30)
#define IORING_URING_CMD_POLLED (1U << 31)
struct io_uring_cmd {
@ -85,6 +89,9 @@ static inline void io_uring_free(struct task_struct *tsk)
__io_uring_free(tsk);
}
int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags);
void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
unsigned int issue_flags);
struct task_struct *io_uring_cmd_get_task(struct io_uring_cmd *cmd);
#else
static inline int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
struct iov_iter *iter, void *ioucmd)
@ -125,6 +132,14 @@ static inline int io_uring_cmd_sock(struct io_uring_cmd *cmd,
{
return -EOPNOTSUPP;
}
static inline void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
}
static inline struct task_struct *io_uring_cmd_get_task(struct io_uring_cmd *cmd)
{
return NULL;
}
#endif
#endif

6
include/linux/io_uring_types.h
View File

@ -265,6 +265,12 @@ struct io_ring_ctx {
*/
struct io_wq_work_list iopoll_list;
bool poll_multi_queue;
/*
* Any cancelable uring_cmd is added to this list in
* ->uring_cmd() by io_uring_cmd_insert_cancelable()
*/
struct hlist_head cancelable_uring_cmd;
} ____cacheline_aligned_in_smp;
struct {

33
io_uring/io_uring.c
View File

@ -352,6 +352,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
INIT_HLIST_HEAD(&ctx->waitid_list);
INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);
return ctx;
err:
kfree(ctx->cancel_table.hbs);
@ -3258,6 +3259,37 @@ static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
return ret;
}
static bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx,
struct task_struct *task, bool cancel_all)
{
struct hlist_node *tmp;
struct io_kiocb *req;
bool ret = false;
lockdep_assert_held(&ctx->uring_lock);
hlist_for_each_entry_safe(req, tmp, &ctx->cancelable_uring_cmd,
hash_node) {
struct io_uring_cmd *cmd = io_kiocb_to_cmd(req,
struct io_uring_cmd);
struct file *file = req->file;
if (!cancel_all && req->task != task)
continue;
if (cmd->flags & IORING_URING_CMD_CANCELABLE) {
/* ->sqe isn't available if no async data */
if (!req_has_async_data(req))
cmd->sqe = NULL;
file->f_op->uring_cmd(cmd, IO_URING_F_CANCEL);
ret = true;
}
}
io_submit_flush_completions(ctx);
return ret;
}
static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
struct task_struct *task,
bool cancel_all)
@ -3306,6 +3338,7 @@ static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
mutex_lock(&ctx->uring_lock);
ret |= io_poll_remove_all(ctx, task, cancel_all);
ret |= io_waitid_remove_all(ctx, task, cancel_all);
ret |= io_uring_try_cancel_uring_cmd(ctx, task, cancel_all);
mutex_unlock(&ctx->uring_lock);
ret |= io_kill_timeouts(ctx, task, cancel_all);
if (task)

47
io_uring/uring_cmd.c
View File

@ -13,6 +13,51 @@
#include "rsrc.h"
#include "uring_cmd.h"
static void io_uring_cmd_del_cancelable(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
struct io_kiocb *req = cmd_to_io_kiocb(cmd);
struct io_ring_ctx *ctx = req->ctx;
if (!(cmd->flags & IORING_URING_CMD_CANCELABLE))
return;
cmd->flags &= ~IORING_URING_CMD_CANCELABLE;
io_ring_submit_lock(ctx, issue_flags);
hlist_del(&req->hash_node);
io_ring_submit_unlock(ctx, issue_flags);
}
/*
* Mark this command as concelable, then io_uring_try_cancel_uring_cmd()
* will try to cancel this issued command by sending ->uring_cmd() with
* issue_flags of IO_URING_F_CANCEL.
*
* The command is guaranteed to not be done when calling ->uring_cmd()
* with IO_URING_F_CANCEL, but it is driver's responsibility to deal
* with race between io_uring canceling and normal completion.
*/
void io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
struct io_kiocb *req = cmd_to_io_kiocb(cmd);
struct io_ring_ctx *ctx = req->ctx;
if (!(cmd->flags & IORING_URING_CMD_CANCELABLE)) {
cmd->flags |= IORING_URING_CMD_CANCELABLE;
io_ring_submit_lock(ctx, issue_flags);
hlist_add_head(&req->hash_node, &ctx->cancelable_uring_cmd);
io_ring_submit_unlock(ctx, issue_flags);
}
}
EXPORT_SYMBOL_GPL(io_uring_cmd_mark_cancelable);
struct task_struct *io_uring_cmd_get_task(struct io_uring_cmd *cmd)
{
return cmd_to_io_kiocb(cmd)->task;
}
EXPORT_SYMBOL_GPL(io_uring_cmd_get_task);
static void io_uring_cmd_work(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
@ -56,6 +101,8 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2,
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
io_uring_cmd_del_cancelable(ioucmd, issue_flags);
if (ret < 0)
req_set_fail(req);