Commit 3ae82f44 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Greg Kroah-Hartman
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drivers/staging/exfat: Replace binary semaphores for mutexes 



At a slight footprint cost (24 vs 32 bytes), mutexes are more optimal
than semaphores; it's also a nicer interface for mutual exclusion,
which is why they are encouraged over binary semaphores, when possible.

For both v_sem and z_sem, their semantics imply traditional lock
ownership; that is, the lock owner is the same for both lock/unlock
operations. Therefore it is safe to convert.

Signed-off-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Acked-by: default avatarValdis Kletnieks <valdis.kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191030144916.10802-1-dave@stgolabs.net


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ebc8f4f6

drivers/staging/exfat/exfat.h

+1 −1
Original line number Diff line number Diff line
@@ -610,7 +610,7 @@ struct fs_info_t { 
	u32 dev_ejected;	/* block device operation error flag */



	struct fs_func *fs_func;

	struct semaphore v_sem;

	struct mutex v_mutex;



	/* FAT cache */

	struct buf_cache_t FAT_cache_array[FAT_CACHE_SIZE];

drivers/staging/exfat/exfat_super.c

+42 −42
Original line number Diff line number Diff line
@@ -284,7 +284,7 @@ static const struct dentry_operations exfat_dentry_ops = { 
	.d_compare      = exfat_cmp,

};



static DEFINE_SEMAPHORE(z_sem);

static DEFINE_MUTEX(z_mutex);



static inline void fs_sync(struct super_block *sb, bool do_sync)

{
@@ -353,11 +353,11 @@ static int ffsMountVol(struct super_block *sb) 


	pr_info("[EXFAT] trying to mount...\n");



	down(&z_sem);

	mutex_lock(&z_mutex);



	buf_init(sb);



	sema_init(&p_fs->v_sem, 1);

	mutex_init(&p_fs->v_mutex);

	p_fs->dev_ejected = 0;



	/* open the block device */
@@ -442,7 +442,7 @@ static int ffsMountVol(struct super_block *sb) 
	pr_info("[EXFAT] mounted successfully\n");



out:

	up(&z_sem);

	mutex_unlock(&z_mutex);



	return ret;

}
@@ -454,10 +454,10 @@ static int ffsUmountVol(struct super_block *sb) 


	pr_info("[EXFAT] trying to unmount...\n");



	down(&z_sem);

	mutex_lock(&z_mutex);



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	fs_sync(sb, true);

	fs_set_vol_flags(sb, VOL_CLEAN);
@@ -481,8 +481,8 @@ static int ffsUmountVol(struct super_block *sb) 
	buf_shutdown(sb);



	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	up(&z_sem);

	mutex_unlock(&p_fs->v_mutex);

	mutex_unlock(&z_mutex);



	pr_info("[EXFAT] unmounted successfully\n");
@@ -499,7 +499,7 @@ static int ffsGetVolInfo(struct super_block *sb, struct vol_info_t *info) 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	if (p_fs->used_clusters == UINT_MAX)

		p_fs->used_clusters = p_fs->fs_func->count_used_clusters(sb);
@@ -514,7 +514,7 @@ static int ffsGetVolInfo(struct super_block *sb, struct vol_info_t *info) 
		err = FFS_MEDIAERR;



	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return err;

}
@@ -525,7 +525,7 @@ static int ffsSyncVol(struct super_block *sb, bool do_sync) 
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* synchronize the file system */

	fs_sync(sb, do_sync);
@@ -535,7 +535,7 @@ static int ffsSyncVol(struct super_block *sb, bool do_sync) 
		err = FFS_MEDIAERR;



	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return err;

}
@@ -562,7 +562,7 @@ static int ffsLookupFile(struct inode *inode, char *path, struct file_id_t *fid) 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* check the validity of directory name in the given pathname */

	ret = resolve_path(inode, path, &dir, &uni_name);
@@ -636,7 +636,7 @@ static int ffsLookupFile(struct inode *inode, char *path, struct file_id_t *fid) 
		ret = FFS_MEDIAERR;

out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -655,7 +655,7 @@ static int ffsCreateFile(struct inode *inode, char *path, u8 mode, 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* check the validity of directory name in the given pathname */

	ret = resolve_path(inode, path, &dir, &uni_name);
@@ -677,7 +677,7 @@ static int ffsCreateFile(struct inode *inode, char *path, u8 mode, 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -704,7 +704,7 @@ static int ffsReadFile(struct inode *inode, struct file_id_t *fid, void *buffer, 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* check if the given file ID is opened */

	if (fid->type != TYPE_FILE) {
@@ -801,7 +801,7 @@ err_out: 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -834,7 +834,7 @@ static int ffsWriteFile(struct inode *inode, struct file_id_t *fid, 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* check if the given file ID is opened */

	if (fid->type != TYPE_FILE) {
@@ -1059,7 +1059,7 @@ err_out: 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1082,7 +1082,7 @@ static int ffsTruncateFile(struct inode *inode, u64 old_size, u64 new_size) 
		 new_size);



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* check if the given file ID is opened */

	if (fid->type != TYPE_FILE) {
@@ -1192,7 +1192,7 @@ static int ffsTruncateFile(struct inode *inode, u64 old_size, u64 new_size) 
out:

	pr_debug("%s exited (%d)\n", __func__, ret);

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1240,7 +1240,7 @@ static int ffsMoveFile(struct inode *old_parent_inode, struct file_id_t *fid, 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	update_parent_info(fid, old_parent_inode);
@@ -1338,7 +1338,7 @@ out: 
		ret = FFS_MEDIAERR;

out2:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1357,7 +1357,7 @@ static int ffsRemoveFile(struct inode *inode, struct file_id_t *fid) 
		return FFS_INVALIDFID;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	dir.dir = fid->dir.dir;

	dir.size = fid->dir.size;
@@ -1400,7 +1400,7 @@ static int ffsRemoveFile(struct inode *inode, struct file_id_t *fid) 
		ret = FFS_MEDIAERR;

out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1435,7 +1435,7 @@ static int ffsSetAttr(struct inode *inode, u32 attr) 
	}



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* get the directory entry of given file */

	if (p_fs->vol_type == EXFAT) {
@@ -1489,7 +1489,7 @@ static int ffsSetAttr(struct inode *inode, u32 attr) 
		ret = FFS_MEDIAERR;

out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1513,7 +1513,7 @@ static int ffsReadStat(struct inode *inode, struct dir_entry_t *info) 
	pr_debug("%s entered\n", __func__);



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	if (is_dir) {

		if ((fid->dir.dir == p_fs->root_dir) &&
@@ -1642,7 +1642,7 @@ static int ffsReadStat(struct inode *inode, struct dir_entry_t *info) 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	pr_debug("%s exited successfully\n", __func__);

	return ret;
@@ -1663,7 +1663,7 @@ static int ffsWriteStat(struct inode *inode, struct dir_entry_t *info) 
	pr_debug("%s entered (inode %p info %p\n", __func__, inode, info);



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	if (is_dir) {

		if ((fid->dir.dir == p_fs->root_dir) &&
@@ -1729,7 +1729,7 @@ static int ffsWriteStat(struct inode *inode, struct dir_entry_t *info) 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	pr_debug("%s exited (%d)\n", __func__, ret);
@@ -1755,7 +1755,7 @@ static int ffsMapCluster(struct inode *inode, s32 clu_offset, u32 *clu) 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	fid->rwoffset = (s64)(clu_offset) << p_fs->cluster_size_bits;
@@ -1883,7 +1883,7 @@ static int ffsMapCluster(struct inode *inode, s32 clu_offset, u32 *clu) 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1907,7 +1907,7 @@ static int ffsCreateDir(struct inode *inode, char *path, struct file_id_t *fid) 
		return FFS_ERROR;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	/* check the validity of directory name in the given old pathname */

	ret = resolve_path(inode, path, &dir, &uni_name);
@@ -1927,7 +1927,7 @@ static int ffsCreateDir(struct inode *inode, char *path, struct file_id_t *fid) 
		ret = FFS_MEDIAERR;

out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -1957,7 +1957,7 @@ static int ffsReadDir(struct inode *inode, struct dir_entry_t *dir_entry) 
		return -EPERM;



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	if (fid->entry == -1) {

		dir.dir = p_fs->root_dir;
@@ -2126,7 +2126,7 @@ static int ffsReadDir(struct inode *inode, struct dir_entry_t *dir_entry) 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -2156,7 +2156,7 @@ static int ffsRemoveDir(struct inode *inode, struct file_id_t *fid) 
	}



	/* acquire the lock for file system critical section */

	down(&p_fs->v_sem);

	mutex_lock(&p_fs->v_mutex);



	clu_to_free.dir = fid->start_clu;

	clu_to_free.size = (s32)((fid->size - 1) >> p_fs->cluster_size_bits) + 1;
@@ -2189,7 +2189,7 @@ static int ffsRemoveDir(struct inode *inode, struct file_id_t *fid) 


out:

	/* release the lock for file system critical section */

	up(&p_fs->v_sem);

	mutex_unlock(&p_fs->v_mutex);



	return ret;

}
@@ -4036,10 +4036,10 @@ static void exfat_debug_kill_sb(struct super_block *sb) 
			 * invalidate_bdev drops all device cache include

			 * dirty. We use this to simulate device removal.

			 */

			down(&p_fs->v_sem);

			mutex_lock(&p_fs->v_mutex);

			FAT_release_all(sb);

			buf_release_all(sb);

			up(&p_fs->v_sem);

			mutex_unlock(&p_fs->v_mutex);



			invalidate_bdev(bdev);

		}

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