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authorakpm@osdl.org <akpm@osdl.org>2005-05-01 08:58:47 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-05-01 08:58:47 -0700
commitd59dd4620fb8d6422555a9e2b82a707718e68327 (patch)
tree78205657d24efcaa3f8314064951ac3814ed95a7 /kernel
parent0d8d4d42f2d00eb65262b49f4edd4cf7ef4eb6fc (diff)
[PATCH] use smp_mb/wmb/rmb where possible
Replace a number of memory barriers with smp_ variants. This means we won't take the unnecessary hit on UP machines. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kthread.c2
-rw-r--r--kernel/profile.c2
-rw-r--r--kernel/ptrace.c2
-rw-r--r--kernel/stop_machine.c10
-rw-r--r--kernel/sys.c20
-rw-r--r--kernel/timer.c2
6 files changed, 19 insertions, 19 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index e377e224410..f50f174e92d 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -174,7 +174,7 @@ int kthread_stop(struct task_struct *k)
/* Must init completion *before* thread sees kthread_stop_info.k */
init_completion(&kthread_stop_info.done);
- wmb();
+ smp_wmb();
/* Now set kthread_should_stop() to true, and wake it up. */
kthread_stop_info.k = k;
diff --git a/kernel/profile.c b/kernel/profile.c
index a38fa70075f..a66be468c42 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -522,7 +522,7 @@ static int __init create_hash_tables(void)
return 0;
out_cleanup:
prof_on = 0;
- mb();
+ smp_mb();
on_each_cpu(profile_nop, NULL, 0, 1);
for_each_online_cpu(cpu) {
struct page *page;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 88b306c4e84..f5cc1cec0fb 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -135,7 +135,7 @@ int ptrace_attach(struct task_struct *task)
(current->gid != task->sgid) ||
(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
goto bad;
- rmb();
+ smp_rmb();
if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
goto bad;
/* the same process cannot be attached many times */
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index c39ed70af17..6116b25aa7c 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -33,7 +33,7 @@ static int stopmachine(void *cpu)
set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu));
/* Ack: we are alive */
- mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
+ smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
atomic_inc(&stopmachine_thread_ack);
/* Simple state machine */
@@ -43,14 +43,14 @@ static int stopmachine(void *cpu)
local_irq_disable();
irqs_disabled = 1;
/* Ack: irqs disabled. */
- mb(); /* Must read state first. */
+ smp_mb(); /* Must read state first. */
atomic_inc(&stopmachine_thread_ack);
} else if (stopmachine_state == STOPMACHINE_PREPARE
&& !prepared) {
/* Everyone is in place, hold CPU. */
preempt_disable();
prepared = 1;
- mb(); /* Must read state first. */
+ smp_mb(); /* Must read state first. */
atomic_inc(&stopmachine_thread_ack);
}
/* Yield in first stage: migration threads need to
@@ -62,7 +62,7 @@ static int stopmachine(void *cpu)
}
/* Ack: we are exiting. */
- mb(); /* Must read state first. */
+ smp_mb(); /* Must read state first. */
atomic_inc(&stopmachine_thread_ack);
if (irqs_disabled)
@@ -77,7 +77,7 @@ static int stopmachine(void *cpu)
static void stopmachine_set_state(enum stopmachine_state state)
{
atomic_set(&stopmachine_thread_ack, 0);
- wmb();
+ smp_wmb();
stopmachine_state = state;
while (atomic_read(&stopmachine_thread_ack) != stopmachine_num_threads)
cpu_relax();
diff --git a/kernel/sys.c b/kernel/sys.c
index 462d78d5589..df2ddcc6863 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -525,7 +525,7 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
if (new_egid != old_egid)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
if (rgid != (gid_t) -1 ||
(egid != (gid_t) -1 && egid != old_rgid))
@@ -556,7 +556,7 @@ asmlinkage long sys_setgid(gid_t gid)
if(old_egid != gid)
{
current->mm->dumpable=0;
- wmb();
+ smp_wmb();
}
current->gid = current->egid = current->sgid = current->fsgid = gid;
}
@@ -565,7 +565,7 @@ asmlinkage long sys_setgid(gid_t gid)
if(old_egid != gid)
{
current->mm->dumpable=0;
- wmb();
+ smp_wmb();
}
current->egid = current->fsgid = gid;
}
@@ -596,7 +596,7 @@ static int set_user(uid_t new_ruid, int dumpclear)
if(dumpclear)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
current->uid = new_ruid;
return 0;
@@ -653,7 +653,7 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
if (new_euid != old_euid)
{
current->mm->dumpable=0;
- wmb();
+ smp_wmb();
}
current->fsuid = current->euid = new_euid;
if (ruid != (uid_t) -1 ||
@@ -703,7 +703,7 @@ asmlinkage long sys_setuid(uid_t uid)
if (old_euid != uid)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
current->fsuid = current->euid = uid;
current->suid = new_suid;
@@ -748,7 +748,7 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
if (euid != current->euid)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
current->euid = euid;
}
@@ -798,7 +798,7 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
if (egid != current->egid)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
current->egid = egid;
}
@@ -845,7 +845,7 @@ asmlinkage long sys_setfsuid(uid_t uid)
if (uid != old_fsuid)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
current->fsuid = uid;
}
@@ -875,7 +875,7 @@ asmlinkage long sys_setfsgid(gid_t gid)
if (gid != old_fsgid)
{
current->mm->dumpable = 0;
- wmb();
+ smp_wmb();
}
current->fsgid = gid;
key_fsgid_changed(current);
diff --git a/kernel/timer.c b/kernel/timer.c
index ecb3d67c0e1..207aa4f0aa1 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1007,7 +1007,7 @@ asmlinkage long sys_getppid(void)
* Make sure we read the pid before re-reading the
* parent pointer:
*/
- rmb();
+ smp_rmb();
parent = me->group_leader->real_parent;
if (old != parent)
continue;