| Message ID | 20230923025006.2830689-3-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | io_uring: cancelable uring_cmd | expand |
Ming Lei <ming.lei@redhat.com> writes: > 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. I think using ->uring_cmd() with IO_URING_F_CANCEL looks much nicer. thanks for that. Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
On 9/22/23 8:50 PM, Ming Lei wrote: > diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h > index ae08d6f66e62..a0307289bdc7 100644 > --- a/include/linux/io_uring.h > +++ b/include/linux/io_uring.h > @@ -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 one issued command */ > + IO_URING_F_CANCEL = (1 << 11), > }; I'd make that comment: /* set when uring wants to cancel a previously issued command */ > @@ -125,6 +132,15 @@ static inline int io_uring_cmd_sock(struct io_uring_cmd *cmd, > { > return -EOPNOTSUPP; > } > +static inline int io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd, > + unsigned int issue_flags) > +{ > + return -EOPNOTSUPP; > +} Do we need this to return an error? Presumably this will never get called if IO_URING isn't defined, but if it does, it obviously doesn't need to do anything anyway. Seems like it should just be a void, and ditto for the enabled version which can't return an error anyway. > 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 (WARN_ON_ONCE(!file->f_op->uring_cmd)) > + continue; That check belongs in the function that marks it cancelable and adds it to the list. Outside of those minor nits, looks fine to me, and patch 1 does too.
On Thu, Sep 28, 2023 at 02:38:32AM -0600, Jens Axboe wrote: > On 9/22/23 8:50 PM, Ming Lei wrote: > > diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h > > index ae08d6f66e62..a0307289bdc7 100644 > > --- a/include/linux/io_uring.h > > +++ b/include/linux/io_uring.h > > @@ -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 one issued command */ > > + IO_URING_F_CANCEL = (1 << 11), > > }; > > I'd make that comment: > > /* set when uring wants to cancel a previously issued command */ OK. > > > @@ -125,6 +132,15 @@ static inline int io_uring_cmd_sock(struct io_uring_cmd *cmd, > > { > > return -EOPNOTSUPP; > > } > > +static inline int io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd, > > + unsigned int issue_flags) > > +{ > > + return -EOPNOTSUPP; > > +} > > Do we need this to return an error? Presumably this will never get > called if IO_URING isn't defined, but if it does, it obviously doesn't > need to do anything anyway. Seems like it should just be a void, and > ditto for the enabled version which can't return an error anyway. Indeed, 'void' is better. > > > 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 (WARN_ON_ONCE(!file->f_op->uring_cmd)) > > + continue; > > That check belongs in the function that marks it cancelable and adds it > to the list. io_uring_cmd_mark_cancelable() is actually called from ->uring_cmd(), so the check isn't necessary. thanks, Ming
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h index ae08d6f66e62..a0307289bdc7 100644 --- a/include/linux/io_uring.h +++ b/include/linux/io_uring.h @@ -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 one 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); +int 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 +132,15 @@ static inline int io_uring_cmd_sock(struct io_uring_cmd *cmd, { return -EOPNOTSUPP; } +static inline int io_uring_cmd_mark_cancelable(struct io_uring_cmd *cmd, + unsigned int issue_flags) +{ + return -EOPNOTSUPP; +} +static inline struct task_struct *io_uring_cmd_get_task(struct io_uring_cmd *cmd) +{ + return NULL; +} #endif #endif diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index 13d19b9be9f4..1571db76bec1 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -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 { diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 9aedb7202403..9c90cad39059 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -350,6 +350,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) INIT_WQ_LIST(&ctx->locked_free_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); @@ -3256,6 +3257,40 @@ 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 (WARN_ON_ONCE(!file->f_op->uring_cmd)) + continue; + + 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) @@ -3303,6 +3338,7 @@ static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx, ret |= io_cancel_defer_files(ctx, task, cancel_all); mutex_lock(&ctx->uring_lock); ret |= io_poll_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) diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c index a0b0ec5473bf..f2cbfa7f1f7f 100644 --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -13,6 +13,53 @@ #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. + */ +int 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); + } + + return 0; +} +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 +103,8 @@ 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);
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. Cc: Gabriel Krisman Bertazi <krisman@suse.de> Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- include/linux/io_uring.h | 16 +++++++++++ include/linux/io_uring_types.h | 6 +++++ io_uring/io_uring.c | 36 +++++++++++++++++++++++++ io_uring/uring_cmd.c | 49 ++++++++++++++++++++++++++++++++++ 4 files changed, 107 insertions(+)