/* kernel/rwsem.c: R/W semaphores, public implementation
 *
 * Written by David Howells (dhowells@redhat.com).
 * Derived from asm-i386/semaphore.h
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/export.h>
#include <linux/rwsem.h>
#include <linux/atomic.h>

#include "rwsem.h"

/*
 * lock for reading
 */
void __sched down_read(struct rw_semaphore *sem)
{
	might_sleep();
	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
	rwsem_set_reader_owned(sem);
}

EXPORT_SYMBOL(down_read);

/*
 * trylock for reading -- returns 1 if successful, 0 if contention
 */
int down_read_trylock(struct rw_semaphore *sem)
{
	int ret = __down_read_trylock(sem);

	if (ret == 1) {
		rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
		rwsem_set_reader_owned(sem);
	}
	return ret;
}

EXPORT_SYMBOL(down_read_trylock);

/*
 * lock for writing
 */
void __sched down_write(struct rw_semaphore *sem)
{
	might_sleep();
	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
	rwsem_set_owner(sem);
}

EXPORT_SYMBOL(down_write);

/*
 * lock for writing
 */
int __sched down_write_killable(struct rw_semaphore *sem)
{
	might_sleep();
	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);

	if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) {
		rwsem_release(&sem->dep_map, 1, _RET_IP_);
		return -EINTR;
	}

	rwsem_set_owner(sem);
	return 0;
}

EXPORT_SYMBOL(down_write_killable);

/*
 * trylock for writing -- returns 1 if successful, 0 if contention
 */
int down_write_trylock(struct rw_semaphore *sem)
{
	int ret = __down_write_trylock(sem);

	if (ret == 1) {
		rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
		rwsem_set_owner(sem);
	}

	return ret;
}

EXPORT_SYMBOL(down_write_trylock);

/*
 * release a read lock
 */
void up_read(struct rw_semaphore *sem)
{
	rwsem_release(&sem->dep_map, 1, _RET_IP_);

	__up_read(sem);
}

EXPORT_SYMBOL(up_read);

/*
 * release a write lock
 */
void up_write(struct rw_semaphore *sem)
{
	rwsem_release(&sem->dep_map, 1, _RET_IP_);

	rwsem_clear_owner(sem);
	__up_write(sem);
}

EXPORT_SYMBOL(up_write);

/*
 * downgrade write lock to read lock
 */
void downgrade_write(struct rw_semaphore *sem)
{
	/*
	 * lockdep: a downgraded write will live on as a write
	 * dependency.
	 */
	rwsem_set_reader_owned(sem);
	__downgrade_write(sem);
}

EXPORT_SYMBOL(downgrade_write);

#ifdef CONFIG_DEBUG_LOCK_ALLOC

void down_read_nested(struct rw_semaphore *sem, int subclass)
{
	might_sleep();
	rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
	rwsem_set_reader_owned(sem);
}

EXPORT_SYMBOL(down_read_nested);

void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
{
	might_sleep();
	rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_);

	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
	rwsem_set_owner(sem);
}

EXPORT_SYMBOL(_down_write_nest_lock);

void down_read_non_owner(struct rw_semaphore *sem)
{
	might_sleep();

	__down_read(sem);
}

EXPORT_SYMBOL(down_read_non_owner);

void down_write_nested(struct rw_semaphore *sem, int subclass)
{
	might_sleep();
	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);

	LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
	rwsem_set_owner(sem);
}

EXPORT_SYMBOL(down_write_nested);

int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass)
{
	might_sleep();
	rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);

	if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) {
		rwsem_release(&sem->dep_map, 1, _RET_IP_);
		return -EINTR;
	}

	rwsem_set_owner(sem);
	return 0;
}

EXPORT_SYMBOL(down_write_killable_nested);

void up_read_non_owner(struct rw_semaphore *sem)
{
	__up_read(sem);
}

EXPORT_SYMBOL(up_read_non_owner);

#endif


n><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-02-08 09:56:15 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-02-08 09:56:15 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/soc/arc/timers.h?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b'>23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/soc/arc/timers.h?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b'>4aff32d5f2f6fe2f54028bfd4d1b66fdd2f8d281</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/soc/arc/timers.h?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b'>include/soc/arc/timers.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/soc/arc/timers.h?id=926af6273fc683cd98cd0ce7bf0d04a02eed6742'>926af6273fc683cd98cd0ce7bf0d04a02eed6742</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/soc/arc/timers.h?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b&amp;id2=926af6273fc683cd98cd0ce7bf0d04a02eed6742'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/soc/arc/timers.h?id=eeeefd41843218c55a8782a6920f044d9bf6207a'>eeeefd41843218c55a8782a6920f044d9bf6207a</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/soc/arc/timers.h?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b&amp;id2=eeeefd41843218c55a8782a6920f044d9bf6207a'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'for-linus' of git://git.kernel.dk/linux-block</div><div class='commit-msg'>Pull block fix from Jens Axboe:
 "A single fix that should go into 4.10, fixing a regression on some
  devices with the WRITE_SAME command"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: don't try Write Same from __blkdev_issue_zeroout
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=23fbe2cdc1de80120cf9ccd478ac57c3a3a0764b'>Diffstat</a> (limited to 'include/soc/arc/timers.h')</div><table summary='diffstat' class='diffstat'>