Re: [PATCH] ext4: use min() to make code cleaner

kernel test robot
2021-12-18T22:32:08Z

Hi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tytso-ext4/dev]
[also build test WARNING on v5.16-rc5 next-20211217]
[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]

url: https://github.com/0day-ci/linux/commits/cgel-zte-gmail-com/ext4-use-min-to-make-code-cleaner/20211216-171213
base: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
config: arc-randconfig-s032-20211218 (https://download.01.org/0day-ci/archive/20211219/202112190602.FX1i96n9-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 11.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# apt-get install sparse
# sparse version: v0.6.4-dirty
# https://github.com/0day-ci/linux/commit/ff519f2d7d41c154cb0d31a9aebe16ce1f6af7ed
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review cgel-zte-gmail-com/ext4-use-min-to-make-code-cleaner/20211216-171213
git checkout ff519f2d7d41c154cb0d31a9aebe16ce1f6af7ed
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arc SHELL=/bin/bash drivers/iio/accel/ fs/ext4/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

sparse warnings: (new ones prefixed by >>)
>> fs/ext4/super.c:6926:26: sparse: sparse: incompatible types in comparison expression (different type sizes):
>> fs/ext4/super.c:6926:26: sparse: unsigned long *
>> fs/ext4/super.c:6926:26: sparse: unsigned int *
fs/ext4/super.c:2643:46: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected void const *objp @@ got char [noderef] __rcu * @@
fs/ext4/super.c:2643:46: sparse: expected void const *objp
fs/ext4/super.c:2643:46: sparse: got char [noderef] __rcu *
fs/ext4/super.c:2698:51: sparse: sparse: incorrect type in argument 1 (different address spaces) @@ expected char const *cs @@ got char [noderef] __rcu * @@
fs/ext4/super.c:2698:51: sparse: expected char const *cs
fs/ext4/super.c:2698:51: sparse: got char [noderef] __rcu *
fs/ext4/super.c:993:6: sparse: sparse: context imbalance in '__ext4_grp_locked_error' - different lock contexts for basic block
fs/ext4/super.c:3321:9: sparse: sparse: context imbalance in 'ext4_check_descriptors' - different lock contexts for basic block

vim +6926 fs/ext4/super.c

6904
6905 /* Read data from quotafile - avoid pagecache and such because we cannot afford
6906 * acquiring the locks... As quota files are never truncated and quota code
6907 * itself serializes the operations (and no one else should touch the files)
6908 * we don't have to be afraid of races */
6909 static ssize_t ext4_quota_read(struct super_block *sb, int type, char *data,
6910 size_t len, loff_t off)
6911 {
6912 struct inode *inode = sb_dqopt(sb)->files[type];
6913 ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
6914 int offset = off & (sb->s_blocksize - 1);
6915 int tocopy;
6916 size_t toread;
6917 struct buffer_head *bh;
6918 loff_t i_size = i_size_read(inode);
6919
6920 if (off > i_size)
6921 return 0;
6922 if (off+len > i_size)
6923 len = i_size-off;
6924 toread = len;
6925 while (toread > 0) {
> 6926 tocopy = min(sb->s_blocksize - offset, toread);
6927 bh = ext4_bread(NULL, inode, blk, 0);
6928 if (IS_ERR(bh))
6929 return PTR_ERR(bh);
6930 if (!bh) /* A hole? */
6931 memset(data, 0, tocopy);
6932 else
6933 memcpy(data, bh->b_data+offset, tocopy);
6934 brelse(bh);
6935 offset = 0;
6936 toread -= tocopy;
6937 data += tocopy;
6938 blk++;
6939 }
6940 return len;
6941 }
6942

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0-DAY CI Kernel Test Service, Intel Corporation