Revision b22fa62a35d7f2029d757a518d78041822b7c7c1 authored by Pavel Begunkov on 21 October 2021, 12:20:29 UTC, committed by Jens Axboe on 21 October 2021, 17:19:38 UTC
Another change to the API io-wq worker limitation API added in 5.15,
apply the limit to all prior users that already registered a tctx. It
may be confusing as it's now, in particular the change covers the
following 2 cases:

TASK1                   | TASK2
_________________________________________________
ring = create()         |
                        | limit_iowq_workers()
*not limited*           |

TASK1                   | TASK2
_________________________________________________
ring = create()         |
                        | issue_requests()
limit_iowq_workers()    |
                        | *not limited*

A note on locking, it's safe to traverse ->tctx_list as we hold
->uring_lock, but do that after dropping sqd->lock to avoid possible
problems. It's also safe to access tctx->io_wq there because tasks
kill it only after removing themselves from tctx_list, see
io_uring_cancel_generic() -> io_uring_clean_tctx()

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d6e09ecc3545e4dc56e43c906ee3d71b7ae21bed.1634818641.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 parent 4ea672a
Raw File
tonga.h
/* SPDX-License-Identifier: GPL-2.0 */
/* drivers/atm/tonga.h - Efficient Networks Tonga (PCI bridge) declarations */
 
/* Written 1995 by Werner Almesberger, EPFL LRC */
 

#ifndef DRIVER_ATM_TONGA_H
#define DRIVER_ATM_TONGA_H

#define PCI_TONGA_CTRL	0x60	/* control register */

#define END_SWAP_DMA	0x80	/* endian swap on DMA */
#define END_SWAP_BYTE	0x40	/* endian swap on slave byte accesses */
#define END_SWAP_WORD	0x20	/* endian swap on slave word accesses */
#define SEPROM_MAGIC	0x0c	/* obscure required pattern (ASIC only) */
#define SEPROM_DATA	0x02	/* serial EEPROM data (ASIC only) */
#define SEPROM_CLK	0x01	/* serial EEPROM clock (ASIC only) */

#define SEPROM_ESI_BASE	64	/* start of ESI in serial EEPROM */

#endif
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