unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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io-wq: return next work from ->do_work() directly

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It's easier to return next work from ->do_work() than
having an in-out argument. Looks nicer and easier to compile.
Also, merge io_wq_assign_next() into its only user.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-06-25 18:20:54 +03:00 committed by Jens Axboe
parent e883a79d8c
commit f4db7182e0
3 changed files with 27 additions and 40 deletions
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8
fs/io-wq.c
View file

@ -523,9 +523,8 @@ static void io_worker_handle_work(struct io_worker *worker)
work->flags |= IO_WQ_WORK_CANCEL;
hash = io_get_work_hash(work);
linked = old_work = work;
wq->do_work(&linked);
linked = (old_work == linked) ? NULL : linked;
old_work = work;
linked = wq->do_work(work);
work = next_hashed;
if (!work && linked && !io_wq_is_hashed(linked)) {
@ -781,8 +780,7 @@ static void io_run_cancel(struct io_wq_work *work, struct io_wqe *wqe)
struct io_wq_work *old_work = work;
work->flags |= IO_WQ_WORK_CANCEL;
wq->do_work(&work);
work = (work == old_work) ? NULL : work;
work = wq->do_work(work);
wq->free_work(old_work);
} while (work);
}

2
fs/io-wq.h
View file

@ -101,7 +101,7 @@ static inline struct io_wq_work *wq_next_work(struct io_wq_work *work)
}
typedef void (free_work_fn)(struct io_wq_work *);
typedef void (io_wq_work_fn)(struct io_wq_work **);
typedef struct io_wq_work *(io_wq_work_fn)(struct io_wq_work *);
struct io_wq_data {
struct user_struct *user;

57
fs/io_uring.c
View file

@ -895,7 +895,6 @@ enum io_mem_account {
ACCT_PINNED,
};
static void io_wq_submit_work(struct io_wq_work **workptr);
static void io_cqring_fill_event(struct io_kiocb *req, long res);
static void io_put_req(struct io_kiocb *req);
static void io_double_put_req(struct io_kiocb *req);
@ -1773,20 +1772,6 @@ static void io_free_req(struct io_kiocb *req)
}
}
static void io_wq_assign_next(struct io_wq_work **workptr, struct io_kiocb *nxt)
{
struct io_kiocb *link;
const struct io_op_def *def = &io_op_defs[nxt->opcode];
if ((nxt->flags & REQ_F_ISREG) && def->hash_reg_file)
io_wq_hash_work(&nxt->work, file_inode(nxt->file));
*workptr = &nxt->work;
link = io_prep_linked_timeout(nxt);
if (link)
nxt->flags |= REQ_F_QUEUE_TIMEOUT;
}
/*
* Drop reference to request, return next in chain (if there is one) if this
* was the last reference to this request.
@ -1806,24 +1791,29 @@ static void io_put_req(struct io_kiocb *req)
io_free_req(req);
}
static void io_steal_work(struct io_kiocb *req,
struct io_wq_work **workptr)
static struct io_wq_work *io_steal_work(struct io_kiocb *req)
{
/*
* It's in an io-wq worker, so there always should be at least
* one reference, which will be dropped in io_put_work() just
* after the current handler returns.
*
* It also means, that if the counter dropped to 1, then there is
* no asynchronous users left, so it's safe to steal the next work.
*/
if (refcount_read(&req->refs) == 1) {
struct io_kiocb *nxt = NULL;
struct io_kiocb *link, *nxt = NULL;
io_req_find_next(req, &nxt);
if (nxt)
io_wq_assign_next(workptr, nxt);
}
/*
* A ref is owned by io-wq in which context we're. So, if that's the
* last one, it's safe to steal next work. False negatives are Ok,
* it just will be re-punted async in io_put_work()
*/
if (refcount_read(&req->refs) != 1)
return NULL;
io_req_find_next(req, &nxt);
if (!nxt)
return NULL;
if ((nxt->flags & REQ_F_ISREG) && io_op_defs[nxt->opcode].hash_reg_file)
io_wq_hash_work(&nxt->work, file_inode(nxt->file));
link = io_prep_linked_timeout(nxt);
if (link)
nxt->flags |= REQ_F_QUEUE_TIMEOUT;
return &nxt->work;
}
/*
@ -5718,9 +5708,8 @@ static void io_arm_async_linked_timeout(struct io_kiocb *req)
io_queue_linked_timeout(link);
}
static void io_wq_submit_work(struct io_wq_work **workptr)
static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
{
struct io_wq_work *work = *workptr;
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
int ret = 0;
@ -5751,7 +5740,7 @@ static void io_wq_submit_work(struct io_wq_work **workptr)
io_req_complete(req, ret);
}
io_steal_work(req, workptr);
return io_steal_work(req);
}
static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,