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Commit d37d4166 authored by Michael Kerrisk (man-pages)'s avatar Michael Kerrisk (man-pages) Committed by Linus Torvalds
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pipe: move limit checking logic into pipe_set_size() 

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: default avatarMichael Kerrisk <mtk.manpages@gmail.com>
Reviewed-by: default avatarVegard 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f491bd71

fs/pipe.c

+18 −23
Original line number Diff line number Diff line
@@ -1023,9 +1023,24 @@ 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
@@ -1109,28 +1124,9 @@ 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;
@@ -1139,7 +1135,6 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) 
		break;

	}



out:

	__pipe_unlock(pipe);

	return ret;

}