Variable 'err' set but not used.
fs/buffer.c:2613:2: warning: Value stored to 'err' is never read.
Reported-by: Abaci Robot <[email protected]>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4589
Signed-off-by: Jiapeng Chong <[email protected]>
---
fs/buffer.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index d759b105c1e7..c844b5b93a89 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -2580,7 +2580,7 @@ int block_truncate_page(struct address_space *mapping,
struct inode *inode = mapping->host;
struct page *page;
struct buffer_head *bh;
- int err;
+ int err = 0;
blocksize = i_blocksize(inode);
length = offset & (blocksize - 1);
@@ -2593,9 +2593,8 @@ int block_truncate_page(struct address_space *mapping,
iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);
page = grab_cache_page(mapping, index);
- err = -ENOMEM;
if (!page)
- goto out;
+ return -ENOMEM;
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
@@ -2609,7 +2608,6 @@ int block_truncate_page(struct address_space *mapping,
pos += blocksize;
}
- err = 0;
if (!buffer_mapped(bh)) {
WARN_ON(bh->b_size != blocksize);
err = get_block(inode, iblock, bh, 0);
@@ -2633,7 +2631,6 @@ int block_truncate_page(struct address_space *mapping,
zero_user(page, offset, length);
mark_buffer_dirty(bh);
- err = 0;
unlock:
unlock_page(page);
--
2.20.1.7.g153144c
On Wed, Mar 22, 2023 at 02:59:49PM +0800, Jiapeng Chong wrote:
> Variable 'err' set but not used.
>
> fs/buffer.c:2613:2: warning: Value stored to 'err' is never read.
>
> Reported-by: Abaci Robot <[email protected]>
> Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4589
> Signed-off-by: Jiapeng Chong <[email protected]>
> ---
> fs/buffer.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/fs/buffer.c b/fs/buffer.c
> index d759b105c1e7..c844b5b93a89 100644
> --- a/fs/buffer.c
> +++ b/fs/buffer.c
> @@ -2580,7 +2580,7 @@ int block_truncate_page(struct address_space *mapping,
> struct inode *inode = mapping->host;
> struct page *page;
> struct buffer_head *bh;
> - int err;
> + int err = 0;
>
> blocksize = i_blocksize(inode);
> length = offset & (blocksize - 1);
> @@ -2593,9 +2593,8 @@ int block_truncate_page(struct address_space *mapping,
> iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);
>
> page = grab_cache_page(mapping, index);
> - err = -ENOMEM;
> if (!page)
> - goto out;
> + return -ENOMEM;
This change makes the out: label unused.
Hi Jiapeng,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on vfs-idmapping/for-next]
[also build test WARNING on linus/master v6.3-rc3 next-20230322]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jiapeng-Chong/fs-buffer-Remove-redundant-assignment-to-err/20230322-150022
base: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping.git for-next
patch link: https://lore.kernel.org/r/20230322065949.29223-1-jiapeng.chong%40linux.alibaba.com
patch subject: [PATCH] fs/buffer: Remove redundant assignment to err
config: hexagon-randconfig-r036-20230322 (https://download.01.org/0day-ci/archive/20230322/[email protected]/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/3e00c2b4797c228b1939a15506c9ab807d0fa809
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Jiapeng-Chong/fs-buffer-Remove-redundant-assignment-to-err/20230322-150022
git checkout 3e00c2b4797c228b1939a15506c9ab807d0fa809
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[email protected]>
| Link: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
In file included from fs/buffer.c:24:
In file included from include/linux/syscalls.h:88:
In file included from include/trace/syscall.h:7:
In file included from include/linux/trace_events.h:9:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:334:
include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
^
In file included from fs/buffer.c:24:
In file included from include/linux/syscalls.h:88:
In file included from include/trace/syscall.h:7:
In file included from include/linux/trace_events.h:9:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:334:
include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
^
In file included from fs/buffer.c:24:
In file included from include/linux/syscalls.h:88:
In file included from include/trace/syscall.h:7:
In file included from include/linux/trace_events.h:9:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:334:
include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
>> fs/buffer.c:2639:1: warning: unused label 'out' [-Wunused-label]
out:
^~~~
fs/buffer.c:2282:5: warning: stack frame size (2144) exceeds limit (1024) in 'block_read_full_folio' [-Wframe-larger-than]
int block_read_full_folio(struct folio *folio, get_block_t *get_block)
^
79/2144 (3.68%) spills, 2065/2144 (96.32%) variables
8 warnings generated.
vim +/out +2639 fs/buffer.c
^1da177e4c3f41 Linus Torvalds 2005-04-16 2572
^1da177e4c3f41 Linus Torvalds 2005-04-16 2573 int block_truncate_page(struct address_space *mapping,
^1da177e4c3f41 Linus Torvalds 2005-04-16 2574 loff_t from, get_block_t *get_block)
^1da177e4c3f41 Linus Torvalds 2005-04-16 2575 {
09cbfeaf1a5a67 Kirill A. Shutemov 2016-04-01 2576 pgoff_t index = from >> PAGE_SHIFT;
09cbfeaf1a5a67 Kirill A. Shutemov 2016-04-01 2577 unsigned offset = from & (PAGE_SIZE-1);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2578 unsigned blocksize;
54b21a7992a31d Andrew Morton 2006-01-08 2579 sector_t iblock;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2580 unsigned length, pos;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2581 struct inode *inode = mapping->host;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2582 struct page *page;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2583 struct buffer_head *bh;
3e00c2b4797c22 Jiapeng Chong 2023-03-22 2584 int err = 0;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2585
93407472a21b82 Fabian Frederick 2017-02-27 2586 blocksize = i_blocksize(inode);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2587 length = offset & (blocksize - 1);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2588
^1da177e4c3f41 Linus Torvalds 2005-04-16 2589 /* Block boundary? Nothing to do */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2590 if (!length)
^1da177e4c3f41 Linus Torvalds 2005-04-16 2591 return 0;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2592
^1da177e4c3f41 Linus Torvalds 2005-04-16 2593 length = blocksize - length;
09cbfeaf1a5a67 Kirill A. Shutemov 2016-04-01 2594 iblock = (sector_t)index << (PAGE_SHIFT - inode->i_blkbits);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2595
^1da177e4c3f41 Linus Torvalds 2005-04-16 2596 page = grab_cache_page(mapping, index);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2597 if (!page)
3e00c2b4797c22 Jiapeng Chong 2023-03-22 2598 return -ENOMEM;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2599
^1da177e4c3f41 Linus Torvalds 2005-04-16 2600 if (!page_has_buffers(page))
^1da177e4c3f41 Linus Torvalds 2005-04-16 2601 create_empty_buffers(page, blocksize, 0);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2602
^1da177e4c3f41 Linus Torvalds 2005-04-16 2603 /* Find the buffer that contains "offset" */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2604 bh = page_buffers(page);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2605 pos = blocksize;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2606 while (offset >= pos) {
^1da177e4c3f41 Linus Torvalds 2005-04-16 2607 bh = bh->b_this_page;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2608 iblock++;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2609 pos += blocksize;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2610 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2611
^1da177e4c3f41 Linus Torvalds 2005-04-16 2612 if (!buffer_mapped(bh)) {
b0cf2321c65991 Badari Pulavarty 2006-03-26 2613 WARN_ON(bh->b_size != blocksize);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2614 err = get_block(inode, iblock, bh, 0);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2615 if (err)
^1da177e4c3f41 Linus Torvalds 2005-04-16 2616 goto unlock;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2617 /* unmapped? It's a hole - nothing to do */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2618 if (!buffer_mapped(bh))
^1da177e4c3f41 Linus Torvalds 2005-04-16 2619 goto unlock;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2620 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2621
^1da177e4c3f41 Linus Torvalds 2005-04-16 2622 /* Ok, it's mapped. Make sure it's up-to-date */
^1da177e4c3f41 Linus Torvalds 2005-04-16 2623 if (PageUptodate(page))
^1da177e4c3f41 Linus Torvalds 2005-04-16 2624 set_buffer_uptodate(bh);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2625
33a266dda9fbbe David Chinner 2007-02-12 2626 if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) {
e7ea1129afab0e Zhang Yi 2022-09-01 2627 err = bh_read(bh, 0);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2628 /* Uhhuh. Read error. Complain and punt. */
e7ea1129afab0e Zhang Yi 2022-09-01 2629 if (err < 0)
^1da177e4c3f41 Linus Torvalds 2005-04-16 2630 goto unlock;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2631 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 2632
eebd2aa355692a Christoph Lameter 2008-02-04 2633 zero_user(page, offset, length);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2634 mark_buffer_dirty(bh);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2635
^1da177e4c3f41 Linus Torvalds 2005-04-16 2636 unlock:
^1da177e4c3f41 Linus Torvalds 2005-04-16 2637 unlock_page(page);
09cbfeaf1a5a67 Kirill A. Shutemov 2016-04-01 2638 put_page(page);
^1da177e4c3f41 Linus Torvalds 2005-04-16 @2639 out:
^1da177e4c3f41 Linus Torvalds 2005-04-16 2640 return err;
^1da177e4c3f41 Linus Torvalds 2005-04-16 2641 }
1fe72eaa0f46a0 H Hartley Sweeten 2009-09-22 2642 EXPORT_SYMBOL(block_truncate_page);
^1da177e4c3f41 Linus Torvalds 2005-04-16 2643
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests