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pipe: move limit checking logic into pipe_set_size() 

commit d37d41666408102bf0ac8e48d8efdce7b809e5f6 upstream.

This is a preparatory patch for following work. Move the F_SETPIPE_SZ
limit-checking logic from pipe_fcntl() into pipe_set_size().  This
simplifies the code a little, and allows for reworking required in
a later patch that fixes the limit checking in pipe_set_size()

Link: http://lkml.kernel.org/r/3701b2c5-2c52-2c3e-226d-29b9deb29b50@gmail.com
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: <socketpair@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Jens Axboe <axboe@fb.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Michael Kerrisk (man-pages) 2016-10-11 13:53:25 -07:00 committed by syphyr
parent 62a3f8ce98
commit 45a24d1e64
1 changed files with 18 additions and 23 deletions
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41
fs/pipe.c
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@ -1219,9 +1219,24 @@ static inline unsigned int round_pipe_size(unsigned int size)
* Allocate a new array of pipe buffers and copy the info over. Returns the
* pipe size if successful, or return -ERROR on error.
*/
static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
{
struct pipe_buffer *bufs;
unsigned int size, nr_pages;
size = round_pipe_size(arg);
nr_pages = size >> PAGE_SHIFT;
if (!nr_pages)
return -EINVAL;
if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size)
return -EPERM;
if ((too_many_pipe_buffers_hard(pipe->user) ||
too_many_pipe_buffers_soft(pipe->user)) &&
!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
return -EPERM;
/*
* We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't
@ -1304,28 +1319,9 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
__pipe_lock(pipe);
switch (cmd) {
case F_SETPIPE_SZ: {
unsigned int size, nr_pages;
size = round_pipe_size(arg);
nr_pages = size >> PAGE_SHIFT;
ret = -EINVAL;
if (!nr_pages)
goto out;
if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
ret = -EPERM;
goto out;
} else if ((too_many_pipe_buffers_hard(pipe->user) ||
too_many_pipe_buffers_soft(pipe->user)) &&
!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
ret = -EPERM;
goto out;
}
ret = pipe_set_size(pipe, nr_pages);
case F_SETPIPE_SZ:
ret = pipe_set_size(pipe, arg);
break;
}
case F_GETPIPE_SZ:
ret = pipe->buffers * PAGE_SIZE;
break;
@ -1334,7 +1330,6 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
break;
}
out:
__pipe_unlock(pipe);
return ret;
}