Commit a73f8844 authored Sep 08, 2010 by Jonathan Corbet Committed by Linus Torvalds Sep 09, 2010

lglock: make lg_lock_global() actually lock globally



lg_lock_global() currently only acquires spinlocks for online CPUs, but
it's meant to lock all possible CPUs.  Lglock-protected resources may be
associated with removed CPUs - and, indeed, that could happen with the
per-superblock open files lists.

At Nick's suggestion, change for_each_online_cpu() to
for_each_possible_cpu() to protect accesses to those resources.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 39aa3cb3

include/linux/lglock.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -150,7 +150,7 @@
		int i; \
		preempt_disable(); \
		rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_); \
		for_each_online_cpu(i) { \
		for_each_possible_cpu(i) { \
		arch_spinlock_t *lock; \
		lock = &per_cpu(name##_lock, i); \
		arch_spin_lock(lock); \
		@@ -161,7 +161,7 @@
		void name##_global_unlock(void) { \
		int i; \
		rwlock_release(&name##_lock_dep_map, 1, _RET_IP_); \
		for_each_online_cpu(i) { \
		for_each_possible_cpu(i) { \
		arch_spinlock_t *lock; \
		lock = &per_cpu(name##_lock, i); \
		arch_spin_unlock(lock); \