/* 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


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>Christian Lamparter &lt;chunkeey@googlemail.com&gt;</td><td class='right'>2017-01-12 13:02:23 +0200</td></tr>
<tr><th>committer</th><td>Kalle Valo &lt;kvalo@qca.qualcomm.com&gt;</td><td class='right'>2017-01-13 15:29:24 +0200</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=1077ec472df43414dafaec126498ff3fc669a471'>1077ec472df43414dafaec126498ff3fc669a471</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers?id=1077ec472df43414dafaec126498ff3fc669a471'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=1077ec472df43414dafaec126498ff3fc669a471'>3ad13b9bba1b9d2f0d9ec49a8783868e8b5ba9d3</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers?id=1077ec472df43414dafaec126498ff3fc669a471'>drivers</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=c1e3330f22bc3c53e6a2c4282dd5a1dc6e6bcca1'>c1e3330f22bc3c53e6a2c4282dd5a1dc6e6bcca1</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers?id=1077ec472df43414dafaec126498ff3fc669a471&amp;id2=c1e3330f22bc3c53e6a2c4282dd5a1dc6e6bcca1'>diff</a>)</td></tr></table>
<div class='commit-subject'>ath9k: move RELAY and DEBUG_FS to ATH9K[_HTC]_DEBUGFS</div><div class='commit-msg'>Currently, the common ath9k_common module needs to have a
dependency on RELAY and DEBUG_FS in order to built. This
is usually not a problem. But for RAM and FLASH starved
AR71XX devices, every little bit counts.

This patch adds a new symbol CONFIG_ATH9K_COMMON_DEBUG
which makes it possible to drop the RELAY and DEBUG_FS
dependency there and move it to ATH_(HTC)_DEBUGFS.

Note: The shared FFT/spectral code (which is the only user
of the relayfs in ath9k*) needs DEBUG_FS to export the relayfs
interface to dump the data to userspace. So it makes no sense
to have the functions compiled in, if DEBUG_FS is not there.

Signed-off-by: Christian Lamparter &lt;chunkeey@googlemail.com&gt;
Signed-off-by: Kalle Valo &lt;kvalo@qca.qualcomm.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=1077ec472df43414dafaec126498ff3fc669a471'>Diffstat</a> (limited to 'drivers')</div><table summary='diffstat' class='diffstat'>