[PATCH] sem2mutex: mm/slab.c

Convert mm/swapfile.c's swapon_sem to swapon_mutex.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 32 insertions, 31 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 9374293a3012..bd0317f1e06c 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -68,7 +68,7 @@
  * Further notes from the original documentation:
  *
  * 11 April '97.  Started multi-threading - markhe
- *      The global cache-chain is protected by the semaphore 'cache_chain_sem'.
+ *      The global cache-chain is protected by the mutex 'cache_chain_mutex'.
  *      The sem is only needed when accessing/extending the cache-chain, which
  *      can never happen inside an interrupt (kmem_cache_create(),
  *      kmem_cache_shrink() and kmem_cache_reap()).
@@ -103,6 +103,7 @@
 #include        <linux/rcupdate.h>
 #include        <linux/string.h>
 #include        <linux/nodemask.h>
+#include        <linux/mutex.h>
 
 #include        <asm/uaccess.h>
 #include        <asm/cacheflush.h>
@@ -631,7 +632,7 @@ static kmem_cache_t cache_cache = {
 };
 
 /* Guard access to the cache-chain. */
-static struct semaphore cache_chain_sem;
+static DEFINE_MUTEX(cache_chain_mutex);
 static struct list_head cache_chain;
 
 /*
@@ -857,7 +858,7 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
 
         switch (action) {
         case CPU_UP_PREPARE:
-                down(&cache_chain_sem);
+                mutex_lock(&cache_chain_mutex);
                 /* we need to do this right in the beginning since
                  * alloc_arraycache's are going to use this list.
                  * kmalloc_node allows us to add the slab to the right
@@ -912,7 +913,7 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
                                 l3->shared = nc;
                         }
                 }
-                up(&cache_chain_sem);
+                mutex_unlock(&cache_chain_mutex);
                 break;
         case CPU_ONLINE:
                 start_cpu_timer(cpu);
@@ -921,7 +922,7 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
         case CPU_DEAD:
                 /* fall thru */
         case CPU_UP_CANCELED:
-                down(&cache_chain_sem);
+                mutex_lock(&cache_chain_mutex);
 
                 list_for_each_entry(cachep, &cache_chain, next) {
                         struct array_cache *nc;
@@ -973,13 +974,13 @@ static int __devinit cpuup_callback(struct notifier_block *nfb,
                         spin_unlock_irq(&cachep->spinlock);
                         kfree(nc);
                 }
-                up(&cache_chain_sem);
+                mutex_unlock(&cache_chain_mutex);
                 break;
 #endif
         }
         return NOTIFY_OK;
       bad:
-        up(&cache_chain_sem);
+        mutex_unlock(&cache_chain_mutex);
         return NOTIFY_BAD;
 }
 
@@ -1047,7 +1048,6 @@ void __init kmem_cache_init(void)
          */
 
         /* 1) create the cache_cache */
-        init_MUTEX(&cache_chain_sem);
         INIT_LIST_HEAD(&cache_chain);
         list_add(&cache_cache.next, &cache_chain);
         cache_cache.colour_off = cache_line_size();
@@ -1168,10 +1168,10 @@ void __init kmem_cache_init(void)
         /* 6) resize the head arrays to their final sizes */
         {
                 kmem_cache_t *cachep;
-                down(&cache_chain_sem);
+                mutex_lock(&cache_chain_mutex);
                 list_for_each_entry(cachep, &cache_chain, next)
                     enable_cpucache(cachep);
-                up(&cache_chain_sem);
+                mutex_unlock(&cache_chain_mutex);
         }
 
         /* Done! */
@@ -1590,7 +1590,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
                 BUG();
         }
 
-        down(&cache_chain_sem);
+        mutex_lock(&cache_chain_mutex);
 
         list_for_each(p, &cache_chain) {
                 kmem_cache_t *pc = list_entry(p, kmem_cache_t, next);
@@ -1856,7 +1856,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,
         if (!cachep && (flags & SLAB_PANIC))
                 panic("kmem_cache_create(): failed to create slab `%s'\n",
                       name);
-        up(&cache_chain_sem);
+        mutex_unlock(&cache_chain_mutex);
         return cachep;
 }
 EXPORT_SYMBOL(kmem_cache_create);
@@ -2044,18 +2044,18 @@ int kmem_cache_destroy(kmem_cache_t *cachep)
         lock_cpu_hotplug();
 
         /* Find the cache in the chain of caches. */
-        down(&cache_chain_sem);
+        mutex_lock(&cache_chain_mutex);
         /*
          * the chain is never empty, cache_cache is never destroyed
          */
         list_del(&cachep->next);
-        up(&cache_chain_sem);
+        mutex_unlock(&cache_chain_mutex);
 
         if (__cache_shrink(cachep)) {
                 slab_error(cachep, "Can't free all objects");
-                down(&cache_chain_sem);
+                mutex_lock(&cache_chain_mutex);
                 list_add(&cachep->next, &cache_chain);
-                up(&cache_chain_sem);
+                mutex_unlock(&cache_chain_mutex);
                 unlock_cpu_hotplug();
                 return 1;
         }
@@ -3314,7 +3314,7 @@ static void drain_array_locked(kmem_cache_t *cachep, struct array_cache *ac,
  * - clear the per-cpu caches for this CPU.
  * - return freeable pages to the main free memory pool.
  *
- * If we cannot acquire the cache chain semaphore then just give up - we'll
+ * If we cannot acquire the cache chain mutex then just give up - we'll
  * try again on the next iteration.
  */
 static void cache_reap(void *unused)
@@ -3322,7 +3322,7 @@ static void cache_reap(void *unused)
         struct list_head *walk;
         struct kmem_list3 *l3;
 
-        if (down_trylock(&cache_chain_sem)) {
+        if (!mutex_trylock(&cache_chain_mutex)) {
                 /* Give up. Setup the next iteration. */
                 schedule_delayed_work(&__get_cpu_var(reap_work),
                                       REAPTIMEOUT_CPUC);
@@ -3393,7 +3393,7 @@ static void cache_reap(void *unused)
                 cond_resched();
         }
         check_irq_on();
-        up(&cache_chain_sem);
+        mutex_unlock(&cache_chain_mutex);
         drain_remote_pages();
         /* Setup the next iteration */
         schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC);
@@ -3429,7 +3429,7 @@ static void *s_start(struct seq_file *m, loff_t *pos)
         loff_t n = *pos;
         struct list_head *p;
 
-        down(&cache_chain_sem);
+        mutex_lock(&cache_chain_mutex);
         if (!n)
                 print_slabinfo_header(m);
         p = cache_chain.next;
@@ -3451,7 +3451,7 @@ static void *s_next(struct seq_file *m, void *p, loff_t *pos)
 
 static void s_stop(struct seq_file *m, void *p)
 {
-        up(&cache_chain_sem);
+        mutex_unlock(&cache_chain_mutex);
 }
 
 static int s_show(struct seq_file *m, void *p)
@@ -3603,7 +3603,7 @@ ssize_t slabinfo_write(struct file *file, const char __user * buffer,
                 return -EINVAL;
 
         /* Find the cache in the chain of caches. */
-        down(&cache_chain_sem);
+        mutex_lock(&cache_chain_mutex);
         res = -EINVAL;
         list_for_each(p, &cache_chain) {
                 kmem_cache_t *cachep = list_entry(p, kmem_cache_t, next);
@@ -3620,7 +3620,7 @@ ssize_t slabinfo_write(struct file *file, const char __user * buffer,
                         break;
                 }
         }
-        up(&cache_chain_sem);
+        mutex_unlock(&cache_chain_mutex);
         if (res >= 0)
                 res = count;
         return res;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 957fef43fa60..f1e69c30d203 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -25,6 +25,7 @@
 #include <linux/rmap.h>
 #include <linux/security.h>
 #include <linux/backing-dev.h>
+#include <linux/mutex.h>
 #include <linux/capability.h>
 #include <linux/syscalls.h>
 
@@ -46,12 +47,12 @@ struct swap_list_t swap_list = {-1, -1};
 
 struct swap_info_struct swap_info[MAX_SWAPFILES];
 
-static DECLARE_MUTEX(swapon_sem);
+static DEFINE_MUTEX(swapon_mutex);
 
 /*
  * We need this because the bdev->unplug_fn can sleep and we cannot
  * hold swap_lock while calling the unplug_fn. And swap_lock
- * cannot be turned into a semaphore.
+ * cannot be turned into a mutex.
  */
 static DECLARE_RWSEM(swap_unplug_sem);
 
@@ -1161,7 +1162,7 @@ asmlinkage long sys_swapoff(const char __user * specialfile)
         up_write(&swap_unplug_sem);
 
         destroy_swap_extents(p);
-        down(&swapon_sem);
+        mutex_lock(&swapon_mutex);
         spin_lock(&swap_lock);
         drain_mmlist();
 
@@ -1180,7 +1181,7 @@ asmlinkage long sys_swapoff(const char __user * specialfile)
         p->swap_map = NULL;
         p->flags = 0;
         spin_unlock(&swap_lock);
-        up(&swapon_sem);
+        mutex_unlock(&swapon_mutex);
         vfree(swap_map);
         inode = mapping->host;
         if (S_ISBLK(inode->i_mode)) {
@@ -1209,7 +1210,7 @@ static void *swap_start(struct seq_file *swap, loff_t *pos)
         int i;
         loff_t l = *pos;
 
-        down(&swapon_sem);
+        mutex_lock(&swapon_mutex);
 
         for (i = 0; i < nr_swapfiles; i++, ptr++) {
                 if (!(ptr->flags & SWP_USED) || !ptr->swap_map)
@@ -1238,7 +1239,7 @@ static void *swap_next(struct seq_file *swap, void *v, loff_t *pos)
 
 static void swap_stop(struct seq_file *swap, void *v)
 {
-        up(&swapon_sem);
+        mutex_unlock(&swapon_mutex);
 }
 
 static int swap_show(struct seq_file *swap, void *v)
@@ -1540,7 +1541,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                 goto bad_swap;
         }
 
-        down(&swapon_sem);
+        mutex_lock(&swapon_mutex);
         spin_lock(&swap_lock);
         p->flags = SWP_ACTIVE;
         nr_swap_pages += nr_good_pages;
@@ -1566,7 +1567,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags)
                 swap_info[prev].next = p - swap_info;
         }
         spin_unlock(&swap_lock);
-        up(&swapon_sem);
+        mutex_unlock(&swapon_mutex);
         error = 0;
         goto out;
 bad_swap: