kernel SPIN_LOCK_UNLOCKED changed to __SPIN_LOCK_UNLOCKED()

There are still some files containing .lock = SPIN_LOCK_UNLOCKED type assignments which should be converted to __SPIN_LOCK_UNLOCKED(). Corrected spacing between __SPIN_LOCK_UNLOCKED and ( for ARM.

Signed-off-by Atul Sowani <[email protected]>

---

diff -uprN a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c

arch/arm/kernel/smp.c +1 -1

@@ -56,7 +56,7 @@ struct ipi_data {
 };
 
 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
-	.lock	= SPIN_LOCK_UNLOCKED,
+	.lock	= __SPIN_LOCK_UNLOCKED(ipi_data.lock),
 };
 
 enum ipi_msg_type {

diff -uprN a/arch/mips/kernel/vpe.c b/arch/mips/kernel/vpe.c

arch/mips/kernel/vpe.c +2 -2

@@ -148,9 +148,9 @@ struct {
 	spinlock_t tc_list_lock;
 	struct list_head tc_list;	/* Thread contexts */
 } vpecontrol = {
-	.vpe_list_lock	= SPIN_LOCK_UNLOCKED,
+	.vpe_list_lock	= __SPIN_LOCK_UNLOCKED(vpecontrol.vpe_list_lock),
 	.vpe_list	= LIST_HEAD_INIT(vpecontrol.vpe_list),
-	.tc_list_lock	= SPIN_LOCK_UNLOCKED,
+	.tc_list_lock	= __SPIN_LOCK_UNLOCKED(vpecontrol.tc_list_lock),
 	.tc_list	= LIST_HEAD_INIT(vpecontrol.tc_list)
 };

diff -uprN a/kernel/cred.c b/kernel/cred.c

kernel/cred.c +1 -1

@@ -35,7 +35,7 @@ static struct kmem_cache *cred_jar;
 static struct thread_group_cred init_tgcred = {
 	.usage	= ATOMIC_INIT(2),
 	.tgid	= 0,
-	.lock	= SPIN_LOCK_UNLOCKED,
+	.lock	= __SPIN_LOCK_UNLOCKED(init_tgcred.lock),
 };
 #endif
 

Signature · 8 lines

Atul Sowani (sowani at gmail.com)
http://savannah.gnu.org/users/atul
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There are still some files containing .lock = SPIN_LOCK_UNLOCKED type assignments which should be converted to __SPIN_LOCK_UNLOCKED(). Corrected spacing between __SPIN_LOCK_UNLOCKED and ( for ARM.

arch/arm/kernel/smp.c 2010-11-07 00:47:32.000000000 +0530 struct ipi_data { · line 60

Quoted 10 lines

diff -uprN a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c

arch/arm/kernel/smp.c 2010-11-07 00:47:32.000000000 +0530 renamed from arch/arm/kernel/smp.c 2010-10-21 02:00:22.000000000 +0530 +1 -1

@@ -56,7 +56,7 @@ struct ipi_data {
 };
 
 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
-     .lock   = SPIN_LOCK_UNLOCKED,
+     .lock   = __SPIN_LOCK_UNLOCKED(ipi_data.lock),
 };

This lock is in the percpu data area. This means that when other CPUs are brought online, and therefore other percpu areas are instantiated, this lock will be mis-initialized (the pointers et.al. will be pointing at the original percpu instance.)

So NAK, this will break.

Quoted 6 lines · On Monday 15 November 2010 10:24:04 Russell King - ARM Linux wrote:

This lock is in the percpu data area. This means that when other CPUs are brought online, and therefore other percpu areas are instantiated, this lock will be mis-initialized (the pointers et.al. will be pointing at the original percpu instance.)

So NAK, this will break.

I believe right now we only use the argument of __SPIN_LOCK_UNLOCKED as an identifier string for lockdep, but not for any pointers, so the patch would actually do what was intended, but break if we ever start relying on the pointer.

Maybe we can mangle the argument in some way to make sure it will break at build time when that happens, e.g.

     .lock   = __SPIN_LOCK_UNLOCKED(ipi_data.__lock)

This would at least let us remove SPIN_LOCK_UNLOCKED.