Revision 24148d8648e37f8c15bedddfa50d14a31a0582c5 authored by Linus Torvalds on 28 August 2020, 23:23:16 UTC, committed by Linus Torvalds on 28 August 2020, 23:23:16 UTC
Pull io_uring fixes from Jens Axboe: "A few fixes in here, all based on reports and test cases from folks using it. Most of it is stable material as well: - Hashed work cancelation fix (Pavel) - poll wakeup signalfd fix - memlock accounting fix - nonblocking poll retry fix - ensure we never return -ERESTARTSYS for reads - ensure offset == -1 is consistent with preadv2() as documented - IOPOLL -EAGAIN handling fixes - remove useless task_work bounce for block based -EAGAIN retry" * tag 'io_uring-5.9-2020-08-28' of git://git.kernel.dk/linux-block: io_uring: don't bounce block based -EAGAIN retry off task_work io_uring: fix IOPOLL -EAGAIN retries io_uring: clear req->result on IOPOLL re-issue io_uring: make offset == -1 consistent with preadv2/pwritev2 io_uring: ensure read requests go through -ERESTART* transformation io_uring: don't use poll handler if file can't be nonblocking read/written io_uring: fix imbalanced sqo_mm accounting io_uring: revert consumed iov_iter bytes on error io-wq: fix hang after cancelling pending hashed work io_uring: don't recurse on tsk->sighand->siglock with signalfd
once.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/once.h>
#include <linux/random.h>
struct once_work {
struct work_struct work;
struct static_key_true *key;
};
static void once_deferred(struct work_struct *w)
{
struct once_work *work;
work = container_of(w, struct once_work, work);
BUG_ON(!static_key_enabled(work->key));
static_branch_disable(work->key);
kfree(work);
}
static void once_disable_jump(struct static_key_true *key)
{
struct once_work *w;
w = kmalloc(sizeof(*w), GFP_ATOMIC);
if (!w)
return;
INIT_WORK(&w->work, once_deferred);
w->key = key;
schedule_work(&w->work);
}
static DEFINE_SPINLOCK(once_lock);
bool __do_once_start(bool *done, unsigned long *flags)
__acquires(once_lock)
{
spin_lock_irqsave(&once_lock, *flags);
if (*done) {
spin_unlock_irqrestore(&once_lock, *flags);
/* Keep sparse happy by restoring an even lock count on
* this lock. In case we return here, we don't call into
* __do_once_done but return early in the DO_ONCE() macro.
*/
__acquire(once_lock);
return false;
}
return true;
}
EXPORT_SYMBOL(__do_once_start);
void __do_once_done(bool *done, struct static_key_true *once_key,
unsigned long *flags)
__releases(once_lock)
{
*done = true;
spin_unlock_irqrestore(&once_lock, *flags);
once_disable_jump(once_key);
}
EXPORT_SYMBOL(__do_once_done);
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