Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Remove kmem_cache_alloc return value cast.

Coccinelle emits the following warning:

./fs/9p/vfs_inode.c:226:12-29: WARNING: casting value returned by memory allocation function to (struct v9fs_inode *) is useless.

Link: http://lkml.kernel.org/r/1596013140-49744-1-git-send-email-liheng40@huawei.com
Signed-off-by: Li Heng <liheng40@huawei.com>
[Dominique: commit message wording]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

These codes have been commented out since 2007 and lay in kernel
since then. So, it's better to remove them.

Link: http://lkml.kernel.org/r/20200628074337.45895-1-jianyong.wu@arm.com
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

v9fs_mount
  v9fs_session_init
    v9fs_cache_session_get_cookie
      v9fs_random_cachetag                     -->alloc cachetag
      v9ses->fscache = fscache_acquire_cookie  -->maybe NULL
  sb = sget                                    -->fail, goto clunk
clunk_fid:
  v9fs_session_close
    if (v9ses->fscache)                        -->NULL
      kfree(v9ses->cachetag)

Thus memleak happens.

Link: http://lkml.kernel.org/r/20200615012153.89538-1-zhengbin13@huawei.com
Fixes: 60e78d2c993e ("9p: Add fscache support to 9p")
Cc: <stable@vger.kernel.org> # v2.6.32+
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

In the current setattr implementation in 9p, fid is always retrieved
from dentry no matter file instance exists or not. If so, there may be
some info related to opened file instance dropped. So it's better
to retrieve fid from file instance when it is passed to setattr.

for example:
fd=open("tmp", O_RDWR);
ftruncate(fd, 10);

The file context related with the fd will be lost as fid is always
retrieved from dentry, then the backend can't get the info of
file context. It is against the original intention of user and
may lead to bug.

Link: http://lkml.kernel.org/r/20200710101548.10108-1-jianyong.wu@arm.com
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

A proper way to handle O_NONBLOCK would be making the requests and
responses happen asynchronously, but this would require serious code
refactoring.

Link: http://lkml.kernel.org/r/20200205003457.24340-2-l29ah@cock.li
Signed-off-by: Sergey Alirzaev <l29ah@cock.li>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

Fixes coccicheck warning:

fs/9p/vfs_inode.c:146:3-4: Unneeded semicolon

Link: http://lkml.kernel.org/r/1576752517-58292-1-git-send-email-zhengbin13@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
	$ sed -e 's/^        /\t/' -i */Kconfig

Link: http://lkml.kernel.org/r/20191120134340.16770-1-krzk@kernel.org
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>

Pull 9p updates from Dominique Martinet:
 "Some of the usual small fixes and cleanup.

  Small fixes all around:
   - avoid overlayfs copy-up for PRIVATE mmaps
   - KUMSAN uninitialized warning for transport error
   - one syzbot memory leak fix in 9p cache
   - internal API cleanup for v9fs_fill_super"

* tag '9p-for-5.4' of git://github.com/martinetd/linux:
  9p/vfs_super.c: Remove unused parameter data in v9fs_fill_super
  9p/cache.c: Fix memory leak in v9fs_cache_session_get_cookie
  9p: Transport error uninitialized
  9p: avoid attaching writeback_fid on mmap with type PRIVATE

v9fs_fill_super has a param 'void *data' which is unused in the
function.

This patch removes the 'void *data' param in v9fs_fill_super and changes
the parameters in all function calls of v9fs_fill_super.

Link: http://lkml.kernel.org/r/20190523165619.GA4209@bharath12345-Inspiron-5559
Signed-off-by: Bharath Vedartham <linux.bhar@gmail.com>
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>