From 7037c96d8c42965eb93e6b96cf921399c283d431 Mon Sep 17 00:00:00 2001 From: ZhaoLong Wang Date: Thu, 18 Apr 2024 15:07:04 +0800 Subject: ubifs: correct UBIFS_DFS_DIR_LEN macro definition and improve code clarity The UBIFS_DFS_DIR_LEN macro, which defines the maximum length of the UBIFS debugfs directory name, has an incorrect formula and misleading comments. The current formula is (3 + 1 + 2*2 + 1), which assumes that both UBI device number and volume ID are limited to 2 characters. However, UBI device number ranges from 0 to 31 (2 characters), and volume ID ranges from 0 to 127 (up to 3 characters). Although the current code works due to the cancellation of mathematical errors (9 + 1 = 10, which matches the correct UBIFS_DFS_DIR_LEN value), it can lead to confusion and potential issues in the future. This patch aims to improve the code clarity and maintainability by making the following changes: 1. Corrects the UBIFS_DFS_DIR_LEN macro definition to (3 + 1 + 2 + 3 + 1), accommodating the maximum lengths of both UBI device number and volume ID, plus the separators and null terminator. 2. Updates the snprintf calls to use UBIFS_DFS_DIR_LEN instead of UBIFS_DFS_DIR_LEN + 1, removing the unnecessary +1. 3. Modifies the error checks to compare against UBIFS_DFS_DIR_LEN using >= instead of >, aligning with the corrected macro definition. 4. Removes the redundant +1 in the dfs_dir_name array definitions in ubi.h and debug.h. While these changes do not affect the runtime behavior, they make the code more readable, maintainable, and less prone to future errors. v2->v3: - Removes the duplicated UBIFS_DFS_DIR_LEN and UBIFS_DFS_DIR_NAME macro definitions in ubifs.h, as they are already defined in debug.h. Signed-off-by: ZhaoLong Wang Reviewed-by: Zhihao Cheng Signed-off-by: Richard Weinberger --- drivers/mtd/ubi/debug.c | 4 ++-- drivers/mtd/ubi/ubi.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c index d57f52bd2ff3..9ec3b8b6a0aa 100644 --- a/drivers/mtd/ubi/debug.c +++ b/drivers/mtd/ubi/debug.c @@ -598,9 +598,9 @@ int ubi_debugfs_init_dev(struct ubi_device *ubi) if (!IS_ENABLED(CONFIG_DEBUG_FS)) return 0; - n = snprintf(d->dfs_dir_name, UBI_DFS_DIR_LEN + 1, UBI_DFS_DIR_NAME, + n = snprintf(d->dfs_dir_name, UBI_DFS_DIR_LEN, UBI_DFS_DIR_NAME, ubi->ubi_num); - if (n > UBI_DFS_DIR_LEN) { + if (n >= UBI_DFS_DIR_LEN) { /* The array size is too small */ return -EINVAL; } diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index 1aead55090d0..1c9e874e8ede 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -420,7 +420,7 @@ struct ubi_debug_info { unsigned int power_cut_min; unsigned int power_cut_max; unsigned int emulate_failures; - char dfs_dir_name[UBI_DFS_DIR_LEN + 1]; + char dfs_dir_name[UBI_DFS_DIR_LEN]; struct dentry *dfs_dir; struct dentry *dfs_chk_gen; struct dentry *dfs_chk_io; -- cgit v1.2.3