Re: [PATCH -next] ext4: remove unused variable 'mapping'

From: kbuild test robot
Date: Tue Jan 07 2020 - 20:00:48 EST


Hi YueHaibing,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on next-20200106]
[also build test WARNING on ext4/dev tytso-fscrypt/master v5.5-rc5]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url: https://github.com/0day-ci/linux/commits/YueHaibing/ext4-remove-unused-variable-mapping/20200107-142902
base: 9eb1b48ca4ce1406628ffe1a11b684a96e83ca08
config: i386-randconfig-g002-20200107 (attached as .config)
compiler: gcc-7 (Debian 7.5.0-3) 7.5.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

In file included from include/linux/export.h:43:0,
from include/linux/linkage.h:7,
from include/linux/fs.h:5,
from fs/ext4/inode.c:22:
fs/ext4/inode.c: In function 'ext4_page_mkwrite':
fs/ext4/inode.c:5942:23: error: 'mapping' undeclared (first use in this function)
if (page->mapping != mapping || page_offset(page) > size) {
^
include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
>> fs/ext4/inode.c:5942:2: note: in expansion of macro 'if'
if (page->mapping != mapping || page_offset(page) > size) {
^~
fs/ext4/inode.c:5942:23: note: each undeclared identifier is reported only once for each function it appears in
if (page->mapping != mapping || page_offset(page) > size) {
^
include/linux/compiler.h:58:52: note: in definition of macro '__trace_if_var'
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
^~~~
>> fs/ext4/inode.c:5942:2: note: in expansion of macro 'if'
if (page->mapping != mapping || page_offset(page) > size) {
^~

vim +/if +5942 fs/ext4/inode.c

2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5900
401b25aa1a75e7f Souptick Joarder 2018-10-02 5901 vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf)
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5902 {
11bac80004499ea Dave Jiang 2017-02-24 5903 struct vm_area_struct *vma = vmf->vma;
c2ec175c39f6294 Nick Piggin 2009-03-31 5904 struct page *page = vmf->page;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5905 loff_t size;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5906 unsigned long len;
401b25aa1a75e7f Souptick Joarder 2018-10-02 5907 int err;
401b25aa1a75e7f Souptick Joarder 2018-10-02 5908 vm_fault_t ret;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5909 struct file *file = vma->vm_file;
496ad9aa8ef4480 Al Viro 2013-01-23 5910 struct inode *inode = file_inode(file);
9ea7df534ed2a18 Jan Kara 2011-06-24 5911 handle_t *handle;
9ea7df534ed2a18 Jan Kara 2011-06-24 5912 get_block_t *get_block;
9ea7df534ed2a18 Jan Kara 2011-06-24 5913 int retries = 0;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5914
02b016ca7f99229 Theodore Ts'o 2019-06-09 5915 if (unlikely(IS_IMMUTABLE(inode)))
02b016ca7f99229 Theodore Ts'o 2019-06-09 5916 return VM_FAULT_SIGBUS;
02b016ca7f99229 Theodore Ts'o 2019-06-09 5917
8e8ad8a57c75f3b Jan Kara 2012-06-12 5918 sb_start_pagefault(inode->i_sb);
041bbb6d369811e Theodore Ts'o 2012-09-30 5919 file_update_time(vma->vm_file);
ea3d7209ca01da2 Jan Kara 2015-12-07 5920
ea3d7209ca01da2 Jan Kara 2015-12-07 5921 down_read(&EXT4_I(inode)->i_mmap_sem);
7b4cc9787fe35b3 Eric Biggers 2017-04-30 5922
401b25aa1a75e7f Souptick Joarder 2018-10-02 5923 err = ext4_convert_inline_data(inode);
401b25aa1a75e7f Souptick Joarder 2018-10-02 5924 if (err)
7b4cc9787fe35b3 Eric Biggers 2017-04-30 5925 goto out_ret;
7b4cc9787fe35b3 Eric Biggers 2017-04-30 5926
9ea7df534ed2a18 Jan Kara 2011-06-24 5927 /* Delalloc case is easy... */
9ea7df534ed2a18 Jan Kara 2011-06-24 5928 if (test_opt(inode->i_sb, DELALLOC) &&
9ea7df534ed2a18 Jan Kara 2011-06-24 5929 !ext4_should_journal_data(inode) &&
9ea7df534ed2a18 Jan Kara 2011-06-24 5930 !ext4_nonda_switch(inode->i_sb)) {
9ea7df534ed2a18 Jan Kara 2011-06-24 5931 do {
401b25aa1a75e7f Souptick Joarder 2018-10-02 5932 err = block_page_mkwrite(vma, vmf,
9ea7df534ed2a18 Jan Kara 2011-06-24 5933 ext4_da_get_block_prep);
401b25aa1a75e7f Souptick Joarder 2018-10-02 5934 } while (err == -ENOSPC &&
9ea7df534ed2a18 Jan Kara 2011-06-24 5935 ext4_should_retry_alloc(inode->i_sb, &retries));
9ea7df534ed2a18 Jan Kara 2011-06-24 5936 goto out_ret;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5937 }
0e499890c1fd9e0 Darrick J. Wong 2011-05-18 5938
0e499890c1fd9e0 Darrick J. Wong 2011-05-18 5939 lock_page(page);
9ea7df534ed2a18 Jan Kara 2011-06-24 5940 size = i_size_read(inode);
9ea7df534ed2a18 Jan Kara 2011-06-24 5941 /* Page got truncated from under us? */
9ea7df534ed2a18 Jan Kara 2011-06-24 @5942 if (page->mapping != mapping || page_offset(page) > size) {
9ea7df534ed2a18 Jan Kara 2011-06-24 5943 unlock_page(page);
9ea7df534ed2a18 Jan Kara 2011-06-24 5944 ret = VM_FAULT_NOPAGE;
9ea7df534ed2a18 Jan Kara 2011-06-24 5945 goto out;
0e499890c1fd9e0 Darrick J. Wong 2011-05-18 5946 }
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5947
09cbfeaf1a5a67b Kirill A. Shutemov 2016-04-01 5948 if (page->index == size >> PAGE_SHIFT)
09cbfeaf1a5a67b Kirill A. Shutemov 2016-04-01 5949 len = size & ~PAGE_MASK;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5950 else
09cbfeaf1a5a67b Kirill A. Shutemov 2016-04-01 5951 len = PAGE_SIZE;
a827eaffff07c7d Aneesh Kumar K.V 2009-09-09 5952 /*
9ea7df534ed2a18 Jan Kara 2011-06-24 5953 * Return if we have all the buffers mapped. This avoids the need to do
9ea7df534ed2a18 Jan Kara 2011-06-24 5954 * journal_start/journal_stop which can block and take a long time
a827eaffff07c7d Aneesh Kumar K.V 2009-09-09 5955 */
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5956 if (page_has_buffers(page)) {
f19d5870cbf72d4 Tao Ma 2012-12-10 5957 if (!ext4_walk_page_buffers(NULL, page_buffers(page),
f19d5870cbf72d4 Tao Ma 2012-12-10 5958 0, len, NULL,
a827eaffff07c7d Aneesh Kumar K.V 2009-09-09 5959 ext4_bh_unmapped)) {
9ea7df534ed2a18 Jan Kara 2011-06-24 5960 /* Wait so that we don't change page under IO */
1d1d1a767206fbe Darrick J. Wong 2013-02-21 5961 wait_for_stable_page(page);
9ea7df534ed2a18 Jan Kara 2011-06-24 5962 ret = VM_FAULT_LOCKED;
9ea7df534ed2a18 Jan Kara 2011-06-24 5963 goto out;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5964 }
a827eaffff07c7d Aneesh Kumar K.V 2009-09-09 5965 }
a827eaffff07c7d Aneesh Kumar K.V 2009-09-09 5966 unlock_page(page);
9ea7df534ed2a18 Jan Kara 2011-06-24 5967 /* OK, we need to fill the hole... */
9ea7df534ed2a18 Jan Kara 2011-06-24 5968 if (ext4_should_dioread_nolock(inode))
705965bd6dfadc3 Jan Kara 2016-03-08 5969 get_block = ext4_get_block_unwritten;
9ea7df534ed2a18 Jan Kara 2011-06-24 5970 else
9ea7df534ed2a18 Jan Kara 2011-06-24 5971 get_block = ext4_get_block;
9ea7df534ed2a18 Jan Kara 2011-06-24 5972 retry_alloc:
9924a92a8c21757 Theodore Ts'o 2013-02-08 5973 handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE,
9924a92a8c21757 Theodore Ts'o 2013-02-08 5974 ext4_writepage_trans_blocks(inode));
9ea7df534ed2a18 Jan Kara 2011-06-24 5975 if (IS_ERR(handle)) {
9ea7df534ed2a18 Jan Kara 2011-06-24 5976 ret = VM_FAULT_SIGBUS;
9ea7df534ed2a18 Jan Kara 2011-06-24 5977 goto out;
9ea7df534ed2a18 Jan Kara 2011-06-24 5978 }
401b25aa1a75e7f Souptick Joarder 2018-10-02 5979 err = block_page_mkwrite(vma, vmf, get_block);
401b25aa1a75e7f Souptick Joarder 2018-10-02 5980 if (!err && ext4_should_journal_data(inode)) {
f19d5870cbf72d4 Tao Ma 2012-12-10 5981 if (ext4_walk_page_buffers(handle, page_buffers(page), 0,
09cbfeaf1a5a67b Kirill A. Shutemov 2016-04-01 5982 PAGE_SIZE, NULL, do_journal_get_write_access)) {
9ea7df534ed2a18 Jan Kara 2011-06-24 5983 unlock_page(page);
c2ec175c39f6294 Nick Piggin 2009-03-31 5984 ret = VM_FAULT_SIGBUS;
fcbb5515825f1bb Yongqiang Yang 2011-10-26 5985 ext4_journal_stop(handle);
9ea7df534ed2a18 Jan Kara 2011-06-24 5986 goto out;
9ea7df534ed2a18 Jan Kara 2011-06-24 5987 }
9ea7df534ed2a18 Jan Kara 2011-06-24 5988 ext4_set_inode_state(inode, EXT4_STATE_JDATA);
9ea7df534ed2a18 Jan Kara 2011-06-24 5989 }
9ea7df534ed2a18 Jan Kara 2011-06-24 5990 ext4_journal_stop(handle);
401b25aa1a75e7f Souptick Joarder 2018-10-02 5991 if (err == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
9ea7df534ed2a18 Jan Kara 2011-06-24 5992 goto retry_alloc;
9ea7df534ed2a18 Jan Kara 2011-06-24 5993 out_ret:
401b25aa1a75e7f Souptick Joarder 2018-10-02 5994 ret = block_page_mkwrite_return(err);
9ea7df534ed2a18 Jan Kara 2011-06-24 5995 out:
ea3d7209ca01da2 Jan Kara 2015-12-07 5996 up_read(&EXT4_I(inode)->i_mmap_sem);
8e8ad8a57c75f3b Jan Kara 2012-06-12 5997 sb_end_pagefault(inode->i_sb);
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5998 return ret;
2e9ee850355593e Aneesh Kumar K.V 2008-07-11 5999 }
ea3d7209ca01da2 Jan Kara 2015-12-07 6000

:::::: The code at line 5942 was first introduced by commit
:::::: 9ea7df534ed2a18157434a496a12cf073ca00c52 ext4: Rewrite ext4_page_mkwrite() to use generic helpers

:::::: TO: Jan Kara <jack@xxxxxxx>
:::::: CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

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