linux-ext4 - [ext4:dev 40/42] fs/jbd2/journal.c:1718 __jbd2_journal

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Date:   Mon, 7 Jun 2021 13:24:31 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     kbuild@...ts.01.org, Leah Rumancik <leah.rumancik@...il.com>
Cc:     lkp@...el.com, kbuild-all@...ts.01.org, linux-ext4@...r.kernel.org,
        "Theodore Ts'o" <tytso@....edu>
Subject: [ext4:dev 40/42] fs/jbd2/journal.c:1718 __jbd2_journal_erase() warn:
 maybe use && instead of &

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
head:   a492dedb708d287aac857c6799f6f364f3d914b3
commit: 84ed553af7e5c8f3f3de0160ba7eaabcab8b9f7b [40/42] ext4: add discard/zeroout flags to journal flush
config: arm-randconfig-m031-20210604 (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>

smatch warnings:
fs/jbd2/journal.c:1718 __jbd2_journal_erase() warn: maybe use && instead of &

vim +1718 fs/jbd2/journal.c

84ed553af7e5c8 Leah Rumancik 2021-05-18  1701  static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
84ed553af7e5c8 Leah Rumancik 2021-05-18  1702  {
84ed553af7e5c8 Leah Rumancik 2021-05-18  1703  	int err = 0;
84ed553af7e5c8 Leah Rumancik 2021-05-18  1704  	unsigned long block, log_offset; /* logical */
84ed553af7e5c8 Leah Rumancik 2021-05-18  1705  	unsigned long long phys_block, block_start, block_stop; /* physical */
84ed553af7e5c8 Leah Rumancik 2021-05-18  1706  	loff_t byte_start, byte_stop, byte_count;
84ed553af7e5c8 Leah Rumancik 2021-05-18  1707  	struct request_queue *q = bdev_get_queue(journal->j_dev);
84ed553af7e5c8 Leah Rumancik 2021-05-18  1708  
84ed553af7e5c8 Leah Rumancik 2021-05-18  1709  	/* flags must be set to either discard or zeroout */
84ed553af7e5c8 Leah Rumancik 2021-05-18  1710  	if ((flags & ~JBD2_JOURNAL_FLUSH_VALID) || !flags ||
84ed553af7e5c8 Leah Rumancik 2021-05-18  1711  			((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
84ed553af7e5c8 Leah Rumancik 2021-05-18  1712  			(flags & JBD2_JOURNAL_FLUSH_ZEROOUT)))
84ed553af7e5c8 Leah Rumancik 2021-05-18  1713  		return -EINVAL;
84ed553af7e5c8 Leah Rumancik 2021-05-18  1714  
84ed553af7e5c8 Leah Rumancik 2021-05-18  1715  	if (!q)
84ed553af7e5c8 Leah Rumancik 2021-05-18  1716  		return -ENXIO;
84ed553af7e5c8 Leah Rumancik 2021-05-18  1717  
84ed553af7e5c8 Leah Rumancik 2021-05-18 @1718  	if (JBD2_JOURNAL_FLUSH_DISCARD & !blk_queue_discard(q))

JBD2_JOURNAL_FLUSH_DISCARD is 1 so this works, but probably && was
intended.

Using && should be a little bit faster.  blk_queue_discard() is just a
wrapper around test_bit() so it doesn't have side effects.

84ed553af7e5c8 Leah Rumancik 2021-05-18  1719  		return -EOPNOTSUPP;
84ed553af7e5c8 Leah Rumancik 2021-05-18  1720  
84ed553af7e5c8 Leah Rumancik 2021-05-18  1721  	/*
84ed553af7e5c8 Leah Rumancik 2021-05-18  1722  	 * lookup block mapping and issue discard/zeroout for each
84ed553af7e5c8 Leah Rumancik 2021-05-18  1723  	 * contiguous region
84ed553af7e5c8 Leah Rumancik 2021-05-18  1724  	 */
84ed553af7e5c8 Leah Rumancik 2021-05-18  1725  	log_offset = be32_to_cpu(journal->j_superblock->s_first);
84ed553af7e5c8 Leah Rumancik 2021-05-18  1726  	block_start =  ~0ULL;
84ed553af7e5c8 Leah Rumancik 2021-05-18  1727  	for (block = log_offset; block < journal->j_total_len; block++) {
84ed553af7e5c8 Leah Rumancik 2021-05-18  1728  		err = jbd2_journal_bmap(journal, block, &phys_block);
84ed553af7e5c8 Leah Rumancik 2021-05-18  1729  		if (err) {
84ed553af7e5c8 Leah Rumancik 2021-05-18  1730  			pr_err("JBD2: bad block at offset %lu", block);

---
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