openwrt/target/linux/generic/patches-3.8/502-yaffs-Switch-from-semaphores-to-mutexes.patch

From c0c289363e84c53b5872f7c0c5069045096dca07 Mon Sep 17 00:00:00 2001
From: Charles Manning <cdhmanning@gmail.com>
Date: Wed, 3 Nov 2010 16:01:12 +1300
Subject: [PATCH] yaffs: Switch from semaphores to mutexes

commit 73c54aa8c1de3f61a4c211cd47431293a6092f18 upstream.

Mutex is faster and init_MUTEX has been deprecated, so we'll just switch
to mutexes.

Signed-off-by: Charles Manning <cdhmanning@gmail.com>
---
 yaffs_linux.h     |    2 +-
 yaffs_vfs.c       |   24 ++++++++++++------------
 yaffs_vfs_multi.c |   26 +++++++++++++-------------
 3 files changed, 26 insertions(+), 26 deletions(-)

--- a/fs/yaffs2/yaffs_linux.h
+++ b/fs/yaffs2/yaffs_linux.h
@@ -25,7 +25,7 @@ struct yaffs_LinuxContext {
 	struct super_block * superBlock;
 	struct task_struct *bgThread; /* Background thread for this device */
 	int bgRunning;
-        struct semaphore grossLock;     /* Gross locking semaphore */
+	struct mutex grossLock;	/* Gross locking mutex*/
 	__u8 *spareBuffer;      /* For mtdif2 use. Don't know the size of the buffer
 				 * at compile time so we have to allocate it.
 				 */
--- a/fs/yaffs2/yaffs_vfs_glue.c
+++ b/fs/yaffs2/yaffs_vfs_glue.c
@@ -515,14 +515,14 @@ static unsigned yaffs_gc_control_callbac
 static void yaffs_gross_lock(yaffs_dev_t *dev)
 {
 	T(YAFFS_TRACE_LOCK, (TSTR("yaffs locking %p\n"), current));
-	down(&(yaffs_dev_to_lc(dev)->grossLock));
+	mutex_lock(&(yaffs_dev_to_lc(dev)->grossLock));
 	T(YAFFS_TRACE_LOCK, (TSTR("yaffs locked %p\n"), current));
 }
 
 static void yaffs_gross_unlock(yaffs_dev_t *dev)
 {
 	T(YAFFS_TRACE_LOCK, (TSTR("yaffs unlocking %p\n"), current));
-	up(&(yaffs_dev_to_lc(dev)->grossLock));
+	mutex_unlock(&(yaffs_dev_to_lc(dev)->grossLock));
 }
 
 #ifdef YAFFS_COMPILE_EXPORTFS
@@ -2542,7 +2542,7 @@ static void yaffs_read_inode(struct inod
 #endif
 
 static YLIST_HEAD(yaffs_context_list);
-struct semaphore yaffs_context_lock;
+struct mutex yaffs_context_lock;
 
 static void yaffs_put_super(struct super_block *sb)
 {
@@ -2568,9 +2568,9 @@ static void yaffs_put_super(struct super
 
 	yaffs_gross_unlock(dev);
 
-	down(&yaffs_context_lock);
+	mutex_lock(&yaffs_context_lock);
 	ylist_del_init(&(yaffs_dev_to_lc(dev)->contextList));
-	up(&yaffs_context_lock);
+	mutex_unlock(&yaffs_context_lock);
 
 	if (yaffs_dev_to_lc(dev)->spareBuffer) {
 		YFREE(yaffs_dev_to_lc(dev)->spareBuffer);
@@ -3016,7 +3016,7 @@ static struct super_block *yaffs_interna
 	param->skip_checkpt_rd = options.skip_checkpoint_read;
 	param->skip_checkpt_wr = options.skip_checkpoint_write;
 
-	down(&yaffs_context_lock);
+	mutex_lock(&yaffs_context_lock);
 	/* Get a mount id */
 	found = 0;
 	for(mount_id=0; ! found; mount_id++){
@@ -3030,13 +3030,13 @@ static struct super_block *yaffs_interna
 	context->mount_id = mount_id;
 
 	ylist_add_tail(&(yaffs_dev_to_lc(dev)->contextList), &yaffs_context_list);
-	up(&yaffs_context_lock);
+	mutex_unlock(&yaffs_context_lock);
 
         /* Directory search handling...*/
         YINIT_LIST_HEAD(&(yaffs_dev_to_lc(dev)->searchContexts));
         param->remove_obj_fn = yaffs_remove_obj_callback;
 
-	init_MUTEX(&(yaffs_dev_to_lc(dev)->grossLock));
+	mutex_init(&(yaffs_dev_to_lc(dev)->grossLock));
 
 	yaffs_gross_lock(dev);
 
@@ -3268,7 +3268,7 @@ static int yaffs_proc_read(char *page,
 	else {
 		step-=2;
 		
-		down(&yaffs_context_lock);
+		mutex_lock(&yaffs_context_lock);
 
 		/* Locate and print the Nth entry.  Order N-squared but N is small. */
 		ylist_for_each(item, &yaffs_context_list) {
@@ -3287,7 +3287,7 @@ static int yaffs_proc_read(char *page,
 			
 			break;
 		}
-		up(&yaffs_context_lock);
+		mutex_unlock(&yaffs_context_lock);
 	}
 
 	return buf - page < count ? buf - page : count;
@@ -3301,7 +3301,7 @@ static int yaffs_stats_proc_read(char *p
 	char *buf = page;
 	int n = 0;
 
-	down(&yaffs_context_lock);
+	mutex_lock(&yaffs_context_lock);
 
 	/* Locate and print the Nth entry.  Order N-squared but N is small. */
 	ylist_for_each(item, &yaffs_context_list) {
@@ -3317,7 +3317,7 @@ static int yaffs_stats_proc_read(char *p
 				dev->bg_gcs, dev->oldest_dirty_gc_count,
 				dev->n_obj, dev->n_tnodes);
 	}
-	up(&yaffs_context_lock);
+	mutex_unlock(&yaffs_context_lock);
 
 
 	return buf - page < count ? buf - page : count;
@@ -3494,7 +3494,7 @@ static int __init init_yaffs_fs(void)
 
 
 
-	init_MUTEX(&yaffs_context_lock);
+	mutex_init(&yaffs_context_lock);
 
 	/* Install the proc_fs entries */
 	my_proc_entry = create_proc_entry("yaffs",