f2fs: Eliminate usage of uninitialized_var() macro

This is an effort to eliminate the uninitialized_var() macro[1].

The use of this macro is the wrong solution because it forces off ANY
analysis by the compiler for a given variable. It even masks "unused
variable" warnings.

Quoted from Linus[2]:

"It's a horrible thing to use, in that it adds extra cruft to the
source code, and then shuts up a compiler warning (even the _reliable_
warnings from gcc)."

Fix it by remove this variable since it is not needed at all.

[1] https://github.com/KSPP/linux/issues/81
[2] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Suggested-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Link: https://lore.kernel.org/r/20200615085132.166470-1-yanaijie@huawei.com
Signed-off-by: Kees Cook <keescook@chromium.org>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 326c638..3753ba0 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2856,7 +2856,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
        };
 #endif
        int nr_pages;
-       pgoff_t uninitialized_var(writeback_index);
        pgoff_t index;
        pgoff_t end;            /* Inclusive */
        pgoff_t done_index;
@@ -2875,8 +2874,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
                clear_inode_flag(mapping->host, FI_HOT_DATA);
 
        if (wbc->range_cyclic) {
-               writeback_index = mapping->writeback_index; /* prev offset */
-               index = writeback_index;
+               index = mapping->writeback_index; /* prev offset */
                end = -1;
        } else {
                index = wbc->range_start >> PAGE_SHIFT;