btrfs-progs: switch memcmp() to the preferred pattern

Let's not use the ever confusing pattern of "if (!memcmp(...))" with
negated operator and positive expected outcome.

Signed-off-by: David Sterba <dsterba@suse.com>

Author: kdave

btrfs-sb-mod.c

@@ -39,7 +39,7 @@ static int check_csum_superblock(void *sb)
 	btrfs_csum_data(NULL, csum_type, (unsigned char *)sb + BTRFS_CSUM_SIZE,
 			result, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
 
-	return !memcmp(sb, result, csum_size);
+	return (memcmp(sb, result, csum_size) == 0);
 }
 
 static void update_block_csum(void *block)

cmds/filesystem.c

@@ -581,7 +581,7 @@ static int find_and_copy_seed(struct btrfs_fs_devices *seed,
 	struct btrfs_fs_devices *cur_fs;
 
 	list_for_each_entry(cur_fs, fs_uuids, fs_list)
-		if (!memcmp(seed->fsid, cur_fs->fsid, BTRFS_FSID_SIZE))
+		if (memcmp(seed->fsid, cur_fs->fsid, BTRFS_FSID_SIZE) == 0)
 			return copy_fs_devices(copy, cur_fs);
 
 	return 1;

cmds/rescue-chunk-recover.c

@@ -1495,7 +1495,7 @@ open_ctree_with_broken_chunk(struct recover_control *rc)
 		goto out_devices;
 	}
 
-	UASSERT(!memcmp(disk_super->fsid, rc->fs_devices->fsid, BTRFS_FSID_SIZE));
+	UASSERT(memcmp(disk_super->fsid, rc->fs_devices->fsid, BTRFS_FSID_SIZE) == 0);
 	fs_info->sectorsize = btrfs_super_sectorsize(disk_super);
 	fs_info->nodesize = btrfs_super_nodesize(disk_super);
 	fs_info->stripesize = btrfs_super_stripesize(disk_super);
@@ -1507,9 +1507,9 @@ open_ctree_with_broken_chunk(struct recover_control *rc)
 	features = btrfs_super_incompat_flags(disk_super);
 
 	if (features & BTRFS_FEATURE_INCOMPAT_METADATA_UUID)
-		UASSERT(!memcmp(disk_super->metadata_uuid,
+		UASSERT(memcmp(disk_super->metadata_uuid,
 			       fs_info->fs_devices->metadata_uuid,
-			       BTRFS_FSID_SIZE));
+			       BTRFS_FSID_SIZE) == 0);
 
 	btrfs_setup_root(fs_info->chunk_root, fs_info,
 			 BTRFS_CHUNK_TREE_OBJECTID);

common/device-scan.c

@@ -294,8 +294,7 @@ int btrfs_device_already_in_root(struct btrfs_root *root, int fd,
 			btrfs_super_magic(&disk_super) != BTRFS_MAGIC_TEMPORARY)
 		goto out;
 
-	if (!memcmp(disk_super.fsid, root->fs_info->super_copy->fsid,
-		    BTRFS_FSID_SIZE))
+	if (memcmp(disk_super.fsid, root->fs_info->super_copy->fsid, BTRFS_FSID_SIZE) == 0)
 		ret = 1;
 out:
 	return ret;

convert/main.c

@@ -1224,8 +1224,8 @@ static int do_convert(const char *devname, u32 convert_flags, u32 nodesize,
 		goto fail;
 	}
 	btrfs_parse_fs_features_to_string(features_buf, features);
-	if (!memcmp(features, &btrfs_mkfs_default_features,
-		   sizeof(struct btrfs_mkfs_features)))
+	if (memcmp(features, &btrfs_mkfs_default_features,
+		   sizeof(struct btrfs_mkfs_features)) == 0)
 		strcat(features_buf, " (default)");
 
 	if (convert_flags & CONVERT_FLAG_COPY_FSID) {

kernel-shared/disk-io.c

@@ -1580,10 +1580,10 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, struct open_ctree_args *oca
 
 	/* CHECK: ignore_csum_mismatch */
 
-	ASSERT(!memcmp(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE));
+	ASSERT(memcmp(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0);
 	if (btrfs_fs_incompat(fs_info, METADATA_UUID))
-		ASSERT(!memcmp(disk_super->metadata_uuid,
-			       fs_devices->metadata_uuid, BTRFS_FSID_SIZE));
+		ASSERT(memcmp(disk_super->metadata_uuid, fs_devices->metadata_uuid,
+			      BTRFS_FSID_SIZE) == 0);
 
 	fs_info->sectorsize = btrfs_super_sectorsize(disk_super);
 	fs_info->nodesize = btrfs_super_nodesize(disk_super);

kernel-shared/print-tree.c

@@ -1906,7 +1906,7 @@ static int check_csum_sblock(void *sb, int csum_size, u16 csum_type)
 	btrfs_csum_data(csum_type, (u8 *)sb + BTRFS_CSUM_SIZE,
 			result, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
 
-	return !memcmp(sb, result, csum_size);
+	return (memcmp(sb, result, csum_size) == 0);
 }
 
 #define DEF_COMPAT_RO_FLAG_ENTRY(bit_name)		\
@@ -2290,10 +2290,10 @@ void btrfs_print_superblock(struct btrfs_super_block *sb, int full)
 
 	uuid_unparse(sb->dev_item.fsid, buf);
 	if (metadata_uuid_present) {
-		cmp_res = !memcmp(sb->dev_item.fsid, sb->metadata_uuid,
-				 BTRFS_FSID_SIZE);
+		cmp_res = (memcmp(sb->dev_item.fsid, sb->metadata_uuid,
+				 BTRFS_FSID_SIZE) == 0);
 	} else {
-		cmp_res = !memcmp(sb->dev_item.fsid, sb->fsid, BTRFS_FSID_SIZE);
+		cmp_res = (memcmp(sb->dev_item.fsid, sb->fsid, BTRFS_FSID_SIZE) == 0);
 	}
 	printf("dev_item.fsid\t\t%s %s\n", buf,
 	       cmp_res ? "[match]" : "[DON'T MATCH]");

kernel-shared/volumes.c

@@ -314,7 +314,7 @@ static struct btrfs_device *find_device(struct btrfs_fs_devices *fs_devices,
 
 	list_for_each_entry(dev, head, dev_list) {
 		if (dev->devid == devid &&
-		    (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
+		    (!uuid || memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE) == 0)) {
 			return dev;
 		}
 	}
@@ -2321,7 +2321,7 @@ struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
 	cur_devices = fs_info->fs_devices;
 	while (cur_devices) {
 		if (!fsid ||
-		    (!memcmp(cur_devices->metadata_uuid, fsid, BTRFS_FSID_SIZE) ||
+		    (memcmp(cur_devices->metadata_uuid, fsid, BTRFS_FSID_SIZE) == 0 ||
 		     fs_info->ignore_fsid_mismatch)) {
 			device = find_device(cur_devices, devid, uuid);
 			if (device)
@@ -2502,7 +2502,7 @@ static int open_seed_devices(struct btrfs_fs_info *fs_info, u8 *fsid)
 
 	fs_devices = fs_info->fs_devices->seed;
 	while (fs_devices) {
-		if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
+		if (memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE) == 0) {
 			ret = 0;
 			goto out;
 		}