| Message ID | 20161027153256.4121871-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 68edb47f5f71..cf5ec39f907d 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -713,7 +713,7 @@ 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:
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(-) v2: use simpler workaround, as discussed with Chao Yu. -- 2.9.0