pipe: make F_{GET,SET}PIPE_SZ deal with byte sizes (b9598db3) · Commits · 戴 / test

fs/pipe.c

+21 −16

Original line number	Diff line number	Diff line
		@@ -1112,26 +1112,20 @@ SYSCALL_DEFINE1(pipe, int __user *, fildes)
		* 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 arg)
		static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
		{
		struct pipe_buffer *bufs;

		/*
		* Must be a power-of-2 currently
		*/
		if (!is_power_of_2(arg))
		return -EINVAL;

		/*
		* We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't
		* expect a lot of shrink+grow operations, just free and allocate
		* again like we would do for growing. If the pipe currently
		* contains more buffers than arg, then return busy.
		*/
		if (arg < pipe->nrbufs)
		if (nr_pages < pipe->nrbufs)
		return -EBUSY;

		bufs = kcalloc(arg, sizeof(struct pipe_buffer), GFP_KERNEL);
		bufs = kcalloc(nr_pages, sizeof(struct pipe_buffer), GFP_KERNEL);
		if (unlikely(!bufs))
		return -ENOMEM;

		@@ -1152,8 +1146,8 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
		pipe->curbuf = 0;
		kfree(pipe->bufs);
		pipe->bufs = bufs;
		pipe->buffers = arg;
		return arg;
		pipe->buffers = nr_pages;
		return nr_pages * PAGE_SIZE;
		}

		long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
		@@ -1168,19 +1162,30 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
		mutex_lock(&pipe->inode->i_mutex);

		switch (cmd) {
		case F_SETPIPE_SZ:
		if (!capable(CAP_SYS_ADMIN) && arg > pipe_max_pages)
		case F_SETPIPE_SZ: {
		unsigned long nr_pages;

		/*
		* Currently the array must be a power-of-2 size, so adjust
		* upwards if needed.
		*/
		nr_pages = (arg + PAGE_SIZE - 1) >> PAGE_SHIFT;
		nr_pages = roundup_pow_of_two(nr_pages);

		if (!capable(CAP_SYS_ADMIN) && nr_pages > pipe_max_pages)
		return -EPERM;

		/*
		* The pipe needs to be at least 2 pages large to
		* guarantee POSIX behaviour.
		*/
		if (arg < 2)
		if (nr_pages < 2)
		return -EINVAL;
		ret = pipe_set_size(pipe, arg);
		ret = pipe_set_size(pipe, nr_pages);
		break;
		}
		case F_GETPIPE_SZ:
		ret = pipe->buffers;
		ret = pipe->buffers * PAGE_SIZE;
		break;
		default:
		ret = -EINVAL;

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