Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] f2fs: hide a maybe-uninitialized warning | Date | Wed, 2 Nov 2016 14:52:15 +0100 |
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gcc is unsure about the use of last_ofs_in_node, which might happen without a prior initialization:
fs/f2fs//git/arm-soc/fs/f2fs/data.c: In function ‘f2fs_map_blocks’: fs/f2fs/data.c:799:54: warning: ‘last_ofs_in_node’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (prealloc && dn.ofs_in_node != last_ofs_in_node + 1) {
As pointed out by Chao Yu, the code is actually correct as 'prealloc' is only set if the last_ofs_in_node has been set, the two always get updated together.
This initializes last_ofs_in_node to dn.ofs_in_node for each new dnode at the start of the 'next_block' loop, which at that point is a correct initialization as well. I assume that compilers that correctly track the contents of the variables and do not warn about the condition also figure out that they can eliminate the extra assignment here.
Fixes: 46008c6d4232 ("f2fs: support in batch multi blocks preallocation") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- fs/f2fs/data.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index a59ea8e60040..6f01aaddfce9 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -719,7 +719,7 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map, } prealloc = 0; - ofs_in_node = dn.ofs_in_node; + last_ofs_in_node = ofs_in_node = dn.ofs_in_node; end_offset = ADDRS_PER_PAGE(dn.node_page, inode); next_block: -- 2.9.0
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