linux/io_uring/uring_cmd.c
Pavel Begunkov 5f3139fc46 io_uring/cmd: add cmd lazy tw wake helper
We want to use IOU_F_TWQ_LAZY_WAKE in commands. First, introduce a new
cmd tw helper accepting TWQ flags, and then add
io_uring_cmd_do_in_task_laz() that will pass IOU_F_TWQ_LAZY_WAKE and
imply the "lazy" semantics, i.e. it posts no more than 1 CQE and
delaying execution of this tw should not prevent forward progress.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5b9f6716006df7e817f18bd555aee2f8f9c8b0c3.1684154817.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-05-25 08:54:06 -06:00

167 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include <linux/security.h>
#include <linux/nospec.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "rsrc.h"
#include "uring_cmd.h"
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);
unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED;
ioucmd->task_work_cb(ioucmd, issue_flags);
}
void __io_uring_cmd_do_in_task(struct io_uring_cmd *ioucmd,
void (*task_work_cb)(struct io_uring_cmd *, unsigned),
unsigned flags)
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
ioucmd->task_work_cb = task_work_cb;
req->io_task_work.func = io_uring_cmd_work;
__io_req_task_work_add(req, flags);
}
EXPORT_SYMBOL_GPL(__io_uring_cmd_do_in_task);
void io_uring_cmd_do_in_task_lazy(struct io_uring_cmd *ioucmd,
void (*task_work_cb)(struct io_uring_cmd *, unsigned))
{
__io_uring_cmd_do_in_task(ioucmd, task_work_cb, IOU_F_TWQ_LAZY_WAKE);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_do_in_task_lazy);
static inline void io_req_set_cqe32_extra(struct io_kiocb *req,
u64 extra1, u64 extra2)
{
req->extra1 = extra1;
req->extra2 = extra2;
req->flags |= REQ_F_CQE32_INIT;
}
/*
* Called by consumers of io_uring_cmd, if they originally returned
* -EIOCBQUEUED upon receiving the command.
*/
void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2,
unsigned issue_flags)
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
if (req->ctx->flags & IORING_SETUP_CQE32)
io_req_set_cqe32_extra(req, res2, 0);
if (req->ctx->flags & IORING_SETUP_IOPOLL) {
/* order with io_iopoll_req_issued() checking ->iopoll_complete */
smp_store_release(&req->iopoll_completed, 1);
} else {
struct io_tw_state ts = {
.locked = !(issue_flags & IO_URING_F_UNLOCKED),
};
io_req_task_complete(req, &ts);
}
}
EXPORT_SYMBOL_GPL(io_uring_cmd_done);
int io_uring_cmd_prep_async(struct io_kiocb *req)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
memcpy(req->async_data, ioucmd->sqe, uring_sqe_size(req->ctx));
ioucmd->sqe = req->async_data;
return 0;
}
int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
if (sqe->__pad1)
return -EINVAL;
ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);
if (ioucmd->flags & ~IORING_URING_CMD_FIXED)
return -EINVAL;
if (ioucmd->flags & IORING_URING_CMD_FIXED) {
struct io_ring_ctx *ctx = req->ctx;
u16 index;
req->buf_index = READ_ONCE(sqe->buf_index);
if (unlikely(req->buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
req->imu = ctx->user_bufs[index];
io_req_set_rsrc_node(req, ctx, 0);
}
ioucmd->sqe = sqe;
ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);
return 0;
}
int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
struct io_ring_ctx *ctx = req->ctx;
struct file *file = req->file;
int ret;
if (!file->f_op->uring_cmd)
return -EOPNOTSUPP;
ret = security_uring_cmd(ioucmd);
if (ret)
return ret;
if (ctx->flags & IORING_SETUP_SQE128)
issue_flags |= IO_URING_F_SQE128;
if (ctx->flags & IORING_SETUP_CQE32)
issue_flags |= IO_URING_F_CQE32;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!file->f_op->uring_cmd_iopoll)
return -EOPNOTSUPP;
issue_flags |= IO_URING_F_IOPOLL;
req->iopoll_completed = 0;
WRITE_ONCE(ioucmd->cookie, NULL);
}
ret = file->f_op->uring_cmd(ioucmd, issue_flags);
if (ret == -EAGAIN) {
if (!req_has_async_data(req)) {
if (io_alloc_async_data(req))
return -ENOMEM;
io_uring_cmd_prep_async(req);
}
return -EAGAIN;
}
if (ret != -EIOCBQUEUED) {
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return ret;
}
return IOU_ISSUE_SKIP_COMPLETE;
}
int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
struct iov_iter *iter, void *ioucmd)
{
struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
return io_import_fixed(rw, iter, req->imu, ubuf, len);
}
EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);