| Message ID | 20220324153644.4079376-1-nathan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: Remove unused variable in btrfs_{start,write}_dirty_block_groups() | expand |
On Thu, Mar 24, 2022 at 08:36:45AM -0700, Nathan Chancellor wrote: > Clang's version of -Wunused-but-set-variable recently gained support for > unary operations, which reveals two unused variables: > > fs/btrfs/block-group.c:2949:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable] > int num_started = 0; > ^ > fs/btrfs/block-group.c:3116:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable] > int num_started = 0; > ^ > 2 errors generated. > > These variables appear to be unused from their introduction, so just > remove them to silence the warnings. > > Cc: stable@vger.kernel.org > Fixes: c9dc4c657850 ("Btrfs: two stage dirty block group writeout") > Fixes: 1bbc621ef284 ("Btrfs: allow block group cache writeout outside critical section in commit") > Link: https://github.com/ClangBuiltLinux/linux/issues/1614 > Signed-off-by: Nathan Chancellor <nathan@kernel.org> Added to misc-next, thanks. > I am requesting a stable backport because this is visible with > allmodconfig, which enables CONFIG_WERROR, breaking the build. Yeah warning fixes are accepted in stable trees and we care about warning-free builds. My gcc 11.1 does not produce any warning with -Wunused-but-set-variable and we have extended the set of warnings in the directory fs/btrfs/ that also includes that one. > To quote Linus: > > "EVERYBODY should have CONFIG_WERROR=y on at least x86-64 and other > serious architectures, unless you have some completely random > experimental (and broken) compiler." I have CONFIG_WERROR disabled, for own development it's quite annoying when build fails outside of the code I care about, while I apply visual checks of warning-free builds.
diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index c22d287e020b..9ad265066225 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -2946,7 +2946,6 @@ int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans) struct btrfs_path *path = NULL; LIST_HEAD(dirty); struct list_head *io = &cur_trans->io_bgs; - int num_started = 0; int loops = 0; spin_lock(&cur_trans->dirty_bgs_lock); @@ -3012,7 +3011,6 @@ int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans) cache->io_ctl.inode = NULL; ret = btrfs_write_out_cache(trans, cache, path); if (ret == 0 && cache->io_ctl.inode) { - num_started++; should_put = 0; /* @@ -3113,7 +3111,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans) int should_put; struct btrfs_path *path; struct list_head *io = &cur_trans->io_bgs; - int num_started = 0; path = btrfs_alloc_path(); if (!path) @@ -3171,7 +3168,6 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans) cache->io_ctl.inode = NULL; ret = btrfs_write_out_cache(trans, cache, path); if (ret == 0 && cache->io_ctl.inode) { - num_started++; should_put = 0; list_add_tail(&cache->io_list, io); } else {
Clang's version of -Wunused-but-set-variable recently gained support for unary operations, which reveals two unused variables: fs/btrfs/block-group.c:2949:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable] int num_started = 0; ^ fs/btrfs/block-group.c:3116:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable] int num_started = 0; ^ 2 errors generated. These variables appear to be unused from their introduction, so just remove them to silence the warnings. Cc: stable@vger.kernel.org Fixes: c9dc4c657850 ("Btrfs: two stage dirty block group writeout") Fixes: 1bbc621ef284 ("Btrfs: allow block group cache writeout outside critical section in commit") Link: https://github.com/ClangBuiltLinux/linux/issues/1614 Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- I am requesting a stable backport because this is visible with allmodconfig, which enables CONFIG_WERROR, breaking the build. To quote Linus: "EVERYBODY should have CONFIG_WERROR=y on at least x86-64 and other serious architectures, unless you have some completely random experimental (and broken) compiler." https://lore.kernel.org/r/CAHk-=wifoM9VOp-55OZCRcO9MnqQ109UTuCiXeZ-eyX_JcNVGg@mail.gmail.com/ fs/btrfs/block-group.c | 4 ---- 1 file changed, 4 deletions(-) base-commit: d3e29967079c522ce1c5cab0e9fab2c280b977eb