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Revision 0e5e098ac22dae38f957e951b70d3cf73beff0f7 authored by Jan Beulich on 11 March 2013, 09:39:55 UTC, committed by Konrad Rzeszutek Wilk on 18 March 2013, 20:31:22 UTC 
xen-blkback: fix dispatch_rw_block_io() error path
 
Commit 7708992 ("xen/blkback: Seperate the bio allocation and the bio
submission") consolidated the pendcnt updates to just a single write,
neglecting the fact that the error path relied on it getting set to 1
up front (such that the decrement in __end_block_io_op() would actually
drop the count to zero, triggering the necessary cleanup actions).

Also remove a misleading and a stale (after said commit) comment.

CC: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
1 parent 986cacb
Raw File
lglock.c 
/* See include/linux/lglock.h for description */
#include <linux/module.h>
#include <linux/lglock.h>
#include <linux/cpu.h>
#include <linux/string.h>

/*
 * Note there is no uninit, so lglocks cannot be defined in
 * modules (but it's fine to use them from there)
 * Could be added though, just undo lg_lock_init
 */

void lg_lock_init(struct lglock *lg, char *name)
{
	LOCKDEP_INIT_MAP(&lg->lock_dep_map, name, &lg->lock_key, 0);
}
EXPORT_SYMBOL(lg_lock_init);

void lg_local_lock(struct lglock *lg)
{
	arch_spinlock_t *lock;

	preempt_disable();
	rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
	lock = this_cpu_ptr(lg->lock);
	arch_spin_lock(lock);
}
EXPORT_SYMBOL(lg_local_lock);

void lg_local_unlock(struct lglock *lg)
{
	arch_spinlock_t *lock;

	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
	lock = this_cpu_ptr(lg->lock);
	arch_spin_unlock(lock);
	preempt_enable();
}
EXPORT_SYMBOL(lg_local_unlock);

void lg_local_lock_cpu(struct lglock *lg, int cpu)
{
	arch_spinlock_t *lock;

	preempt_disable();
	rwlock_acquire_read(&lg->lock_dep_map, 0, 0, _RET_IP_);
	lock = per_cpu_ptr(lg->lock, cpu);
	arch_spin_lock(lock);
}
EXPORT_SYMBOL(lg_local_lock_cpu);

void lg_local_unlock_cpu(struct lglock *lg, int cpu)
{
	arch_spinlock_t *lock;

	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
	lock = per_cpu_ptr(lg->lock, cpu);
	arch_spin_unlock(lock);
	preempt_enable();
}
EXPORT_SYMBOL(lg_local_unlock_cpu);

void lg_global_lock(struct lglock *lg)
{
	int i;

	preempt_disable();
	rwlock_acquire(&lg->lock_dep_map, 0, 0, _RET_IP_);
	for_each_possible_cpu(i) {
		arch_spinlock_t *lock;
		lock = per_cpu_ptr(lg->lock, i);
		arch_spin_lock(lock);
	}
}
EXPORT_SYMBOL(lg_global_lock);

void lg_global_unlock(struct lglock *lg)
{
	int i;

	rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
	for_each_possible_cpu(i) {
		arch_spinlock_t *lock;
		lock = per_cpu_ptr(lg->lock, i);
		arch_spin_unlock(lock);
	}
	preempt_enable();
}
EXPORT_SYMBOL(lg_global_unlock);
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