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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "../kernel/futex/futex.h"
#include "io_uring.h"
#include "rsrc.h"
#include "futex.h"
struct io_futex {
struct file *file;
u32 __user *uaddr;
unsigned long futex_val;
unsigned long futex_mask;
u32 futex_flags;
};
struct io_futex_data {
union {
struct futex_q q;
struct io_cache_entry cache;
};
struct io_kiocb *req;
};
void io_futex_cache_init(struct io_ring_ctx *ctx)
{
io_alloc_cache_init(&ctx->futex_cache, IO_NODE_ALLOC_CACHE_MAX,
sizeof(struct io_futex_data));
}
static void io_futex_cache_entry_free(struct io_cache_entry *entry)
{
kfree(container_of(entry, struct io_futex_data, cache));
}
void io_futex_cache_free(struct io_ring_ctx *ctx)
{
io_alloc_cache_free(&ctx->futex_cache, io_futex_cache_entry_free);
}
static void io_futex_complete(struct io_kiocb *req, struct io_tw_state *ts)
{
struct io_futex_data *ifd = req->async_data;
struct io_ring_ctx *ctx = req->ctx;
io_tw_lock(ctx, ts);
if (!io_alloc_cache_put(&ctx->futex_cache, &ifd->cache))
kfree(ifd);
req->async_data = NULL;
hlist_del_init(&req->hash_node);
io_req_task_complete(req, ts);
}
static bool __io_futex_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
{
struct io_futex_data *ifd = req->async_data;
/* futex wake already done or in progress */
if (!futex_unqueue(&ifd->q))
return false;
hlist_del_init(&req->hash_node);
io_req_set_res(req, -ECANCELED, 0);
req->io_task_work.func = io_futex_complete;
io_req_task_work_add(req);
return true;
}
int io_futex_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
unsigned int issue_flags)
{
struct hlist_node *tmp;
struct io_kiocb *req;
int nr = 0;
if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_FD_FIXED))
return -ENOENT;
io_ring_submit_lock(ctx, issue_flags);
hlist_for_each_entry_safe(req, tmp, &ctx->futex_list, hash_node) {
if (req->cqe.user_data != cd->data &&
!(cd->flags & IORING_ASYNC_CANCEL_ANY))
continue;
if (__io_futex_cancel(ctx, req))
nr++;
if (!(cd->flags & IORING_ASYNC_CANCEL_ALL))
break;
}
io_ring_submit_unlock(ctx, issue_flags);
if (nr)
return nr;
return -ENOENT;
}
bool io_futex_remove_all(struct io_ring_ctx *ctx, struct task_struct *task,
bool cancel_all)
{
struct hlist_node *tmp;
struct io_kiocb *req;
bool found = false;
lockdep_assert_held(&ctx->uring_lock);
hlist_for_each_entry_safe(req, tmp, &ctx->futex_list, hash_node) {
if (!io_match_task_safe(req, task, cancel_all))
continue;
__io_futex_cancel(ctx, req);
found = true;
}
return found;
}
int io_futex_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
u32 flags;
if (unlikely(sqe->len || sqe->futex_flags || sqe->buf_index ||
sqe->file_index))
return -EINVAL;
iof->uaddr = u64_to_user_ptr(READ_ONCE(sqe->addr));
iof->futex_val = READ_ONCE(sqe->addr2);
iof->futex_mask = READ_ONCE(sqe->addr3);
flags = READ_ONCE(sqe->fd);
if (flags & ~FUTEX2_VALID_MASK)
return -EINVAL;
iof->futex_flags = futex2_to_flags(flags);
if (!futex_flags_valid(iof->futex_flags))
return -EINVAL;
if (!futex_validate_input(iof->futex_flags, iof->futex_val) ||
!futex_validate_input(iof->futex_flags, iof->futex_mask))
return -EINVAL;
return 0;
}
static void io_futex_wake_fn(struct wake_q_head *wake_q, struct futex_q *q)
{
struct io_futex_data *ifd = container_of(q, struct io_futex_data, q);
struct io_kiocb *req = ifd->req;
if (unlikely(!__futex_wake_mark(q)))
return;
io_req_set_res(req, 0, 0);
req->io_task_work.func = io_futex_complete;
io_req_task_work_add(req);
}
static struct io_futex_data *io_alloc_ifd(struct io_ring_ctx *ctx)
{
struct io_cache_entry *entry;
entry = io_alloc_cache_get(&ctx->futex_cache);
if (entry)
return container_of(entry, struct io_futex_data, cache);
return kmalloc(sizeof(struct io_futex_data), GFP_NOWAIT);
}
int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
struct io_ring_ctx *ctx = req->ctx;
struct io_futex_data *ifd = NULL;
struct futex_hash_bucket *hb;
int ret;
if (!iof->futex_mask) {
ret = -EINVAL;
goto done;
}
io_ring_submit_lock(ctx, issue_flags);
ifd = io_alloc_ifd(ctx);
if (!ifd) {
ret = -ENOMEM;
goto done_unlock;
}
req->async_data = ifd;
ifd->q = futex_q_init;
ifd->q.bitset = iof->futex_mask;
ifd->q.wake = io_futex_wake_fn;
ifd->req = req;
ret = futex_wait_setup(iof->uaddr, iof->futex_val, iof->futex_flags,
&ifd->q, &hb);
if (!ret) {
hlist_add_head(&req->hash_node, &ctx->futex_list);
io_ring_submit_unlock(ctx, issue_flags);
futex_queue(&ifd->q, hb);
return IOU_ISSUE_SKIP_COMPLETE;
}
done_unlock:
io_ring_submit_unlock(ctx, issue_flags);
done:
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
kfree(ifd);
return IOU_OK;
}
int io_futex_wake(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_futex *iof = io_kiocb_to_cmd(req, struct io_futex);
int ret;
/*
* Strict flags - ensure that waking 0 futexes yields a 0 result.
* See commit 43adf8449510 ("futex: FLAGS_STRICT") for details.
*/
ret = futex_wake(iof->uaddr, FLAGS_STRICT | iof->futex_flags,
iof->futex_val, iof->futex_mask);
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
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