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这是错误

fs/fat/dir.c: In function 'fat_dir_empty': fs/fat/dir.c:124:8: warning: 'de' may be used uninitialized in this function [-Wmaybe-uninitialized] 错误，禁止警告：dir .c:124

static inline int fat_get_entry(struct inode *dir, loff_t *pos,
            struct buffer_head **bh,
            struct msdos_dir_entry **de)
{
/* Fast stuff first */
if (*bh && *de &&
   (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
            MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
    *pos += sizeof(struct msdos_dir_entry);
    (*de)++;
    return 0;
}
return fat__get_entry(dir, pos, bh, de);
}

(*de)++; 是问题

我不明白，具有相同编码的 3.4 编译得很好。对此的任何帮助将不胜感激。

更新：阅读后，http : //lwn.net/Articles/529954/ 我正在运行 -O3 优化，这会影响 -Wmaybe-uninitialized

更新 2： vfat 构建为一个模块，没问题。只有作为内置的问题。我想知道为什么会这样？

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1 回答 1

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来自 Code Aurora 论坛的补丁修复了这个问题。

来自：David Brown 日期：2010 年 10 月 10 日，星期日 23:34:20 -0700 主题：[PATCH] FAT：修复警告

fs/fat/dir.c:43：警告：“de”可能在此函数中未初始化使用

代码流的复杂性使这似乎成为可能。将值初始化为 NULL 以消除编译器警告。这只会掩盖警告，因为如果该值未被使用，仍然会有一个 NULL 指针。

Change-Id: I9fc36abace09409853b63e0997328b75ce703769
Signed-off-by: David Brown <davidb@codeaurora.org>
---
 fs/fat/dir.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 65e174b..409b3ce 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -343,7 +343,7 @@ int fat_search_long(struct inode *inode, const unsigned char *name,
    struct super_block *sb = inode->i_sb;
    struct msdos_sb_info *sbi = MSDOS_SB(sb);
    struct buffer_head *bh = NULL;
-   struct msdos_dir_entry *de;
+   struct msdos_dir_entry *de = NULL;
    struct nls_table *nls_disk = sbi->nls_disk;
    unsigned char nr_slots;
    wchar_t bufuname[14];
@@ -468,7 +468,7 @@ static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
    struct super_block *sb = inode->i_sb;
    struct msdos_sb_info *sbi = MSDOS_SB(sb);
    struct buffer_head *bh;
-   struct msdos_dir_entry *de;
+   struct msdos_dir_entry *de = NULL;
    struct nls_table *nls_disk = sbi->nls_disk;
    unsigned char nr_slots;
    wchar_t bufuname[14];
@@ -887,7 +887,7 @@ EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
 int fat_dir_empty(struct inode *dir)
 {
    struct buffer_head *bh;
-   struct msdos_dir_entry *de;
+   struct msdos_dir_entry *de = NULL;
    loff_t cpos;
    int result = 0;

@@ -913,7 +913,7 @@ EXPORT_SYMBOL_GPL(fat_dir_empty);
 int fat_subdirs(struct inode *dir)
 {
    struct buffer_head *bh;
-   struct msdos_dir_entry *de;
+   struct msdos_dir_entry *de = NULL;
    loff_t cpos;
    int count = 0;

@@ -1240,7 +1240,7 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
    struct super_block *sb = dir->i_sb;
    struct msdos_sb_info *sbi = MSDOS_SB(sb);
    struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
-   struct msdos_dir_entry *uninitialized_var(de);
+   struct msdos_dir_entry *de = NULL;
    int err, free_slots, i, nr_bhs;
    loff_t pos, i_pos;

-- 
2.5.0
于 2015-09-18T19:20:09.593 回答