pipe: change /proc/sys/fs/pipe-max-pages to byte sized interface (ff9da691) · Commits · 戴 / test

fs/pipe.c

+42 −12

Original line number	Diff line number	Diff line
		@@ -26,9 +26,14 @@

		/*
		* The max size that a non-root user is allowed to grow the pipe. Can
		* be set by root in /proc/sys/fs/pipe-max-pages
		* be set by root in /proc/sys/fs/pipe-max-size
		*/
		unsigned int pipe_max_pages = PIPE_DEF_BUFFERS * 16;
		unsigned int pipe_max_size = 1048576;

		/*
		* Minimum pipe size, as required by POSIX
		*/
		unsigned int pipe_min_size = PAGE_SIZE;

		/*
		* We use a start+len construction, which provides full use of the
		@@ -1156,6 +1161,35 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
		return nr_pages * PAGE_SIZE;
		}

		/*
		* Currently we rely on the pipe array holding a power-of-2 number
		* of pages.
		*/
		static inline unsigned int round_pipe_size(unsigned int size)
		{
		unsigned long nr_pages;

		nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
		return roundup_pow_of_two(nr_pages) << PAGE_SHIFT;
		}

		/*
		* This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax
		* will return an error.
		*/
		int pipe_proc_fn(struct ctl_table table, int write, void __user buf,
		size_t lenp, loff_t ppos)
		{
		int ret;

		ret = proc_dointvec_minmax(table, write, buf, lenp, ppos);
		if (ret < 0 \|\| !write)
		return ret;

		pipe_max_size = round_pipe_size(pipe_max_size);
		return ret;
		}

		long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
		{
		struct pipe_inode_info *pipe;
		@@ -1169,23 +1203,19 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)

		switch (cmd) {
		case F_SETPIPE_SZ: {
		unsigned long nr_pages;
		unsigned int size, 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);
		size = round_pipe_size(arg);
		nr_pages = size >> PAGE_SHIFT;

		if (!capable(CAP_SYS_RESOURCE) && nr_pages > pipe_max_pages) {
		if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
		ret = -EPERM;
		goto out;
		} else if (nr_pages < 1) {
		} else if (nr_pages < PAGE_SIZE) {
		ret = -EINVAL;
		goto out;
		}
		ret = pipe_set_size(pipe, arg);
		ret = pipe_set_size(pipe, nr_pages);
		break;
		}
		case F_GETPIPE_SZ:

include/linux/pipe_fs_i.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -139,7 +139,9 @@ void pipe_lock(struct pipe_inode_info *);
		void pipe_unlock(struct pipe_inode_info *);
		void pipe_double_lock(struct pipe_inode_info , struct pipe_inode_info );

		extern unsigned int pipe_max_pages;
		extern unsigned int pipe_max_size, pipe_min_size;
		int pipe_proc_fn(struct ctl_table , int, void __user , size_t , loff_t );


		/* Drop the inode semaphore and wait for a pipe event, atomically */
		void pipe_wait(struct pipe_inode_info *pipe);

kernel/sysctl.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -1471,12 +1471,12 @@ static struct ctl_table fs_table[] = {
		},
		#endif
		{
		.procname = "pipe-max-pages",
		.data = &pipe_max_pages,
		.procname = "pipe-max-size",
		.data = &pipe_max_size,
		.maxlen = sizeof(int),
		.mode = 0644,
		.proc_handler = &proc_dointvec_minmax,
		.extra1 = &two,
		.proc_handler = &pipe_proc_fn,
		.extra1 = &pipe_min_size,
		},
		/*
		* NOTE: do not add new entries to this table unless you have read

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