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Commit 572d34b9 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
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proc: unify mem_read() and mem_write() 



No functional changes, cleanup and preparation.

mem_read() and mem_write() are very similar. Move this code into the
new common helper, mem_rw(), which takes the additional "int write"
argument.

Cc: stable@kernel.org
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 71879d3c

fs/proc/base.c

+32 −58
Original line number Diff line number Diff line
@@ -718,13 +718,13 @@ static int mem_open(struct inode* inode, struct file* file) 
	return 0;

}



static ssize_t mem_read(struct file * file, char __user * buf,

			size_t count, loff_t *ppos)

static ssize_t mem_rw(struct file *file, char __user *buf,

			size_t count, loff_t *ppos, int write)

{

	int ret;

	char *page;

	unsigned long src = *ppos;

	struct mm_struct *mm = file->private_data;

	unsigned long addr = *ppos;

	ssize_t copied;

	char *page;



	if (!mm)

		return 0;
@@ -733,74 +733,48 @@ static ssize_t mem_read(struct file * file, char __user * buf, 
	if (!page)

		return -ENOMEM;



	ret = 0;

 

	copied = 0;

	while (count > 0) {

		int this_len, retval;

		int this_len = min_t(int, count, PAGE_SIZE);



		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;

		retval = access_remote_vm(mm, src, page, this_len, 0);

		if (!retval) {

			if (!ret)

				ret = -EIO;

		if (write && copy_from_user(page, buf, this_len)) {

			copied = -EFAULT;

			break;

		}



		if (copy_to_user(buf, page, retval)) {

			ret = -EFAULT;

		this_len = access_remote_vm(mm, addr, page, this_len, write);

		if (!this_len) {

			if (!copied)

				copied = -EIO;

			break;

		}



		ret += retval;

		src += retval;

		buf += retval;

		count -= retval;

		if (!write && copy_to_user(buf, page, this_len)) {

			copied = -EFAULT;

			break;

		}

	*ppos = src;



		buf += this_len;

		addr += this_len;

		copied += this_len;

		count -= this_len;

	}

	*ppos = addr;



	free_page((unsigned long) page);

	return ret;

	return copied;

}



static ssize_t mem_write(struct file * file, const char __user *buf,

static ssize_t mem_read(struct file *file, char __user *buf,

			size_t count, loff_t *ppos)

{

	int copied;

	char *page;

	unsigned long dst = *ppos;

	struct mm_struct *mm = file->private_data;



	if (!mm)

		return 0;



	page = (char *)__get_free_page(GFP_TEMPORARY);

	if (!page)

		return -ENOMEM;



	copied = 0;

	while (count > 0) {

		int this_len, retval;



		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;

		if (copy_from_user(page, buf, this_len)) {

			copied = -EFAULT;

			break;

	return mem_rw(file, buf, count, ppos, 0);

}

		retval = access_remote_vm(mm, dst, page, this_len, 1);

		if (!retval) {

			if (!copied)

				copied = -EIO;

			break;

		}

		copied += retval;

		buf += retval;

		dst += retval;

		count -= retval;			

	}

	*ppos = dst;



	free_page((unsigned long) page);

	return copied;

static ssize_t mem_write(struct file *file, const char __user *buf,

			 size_t count, loff_t *ppos)

{

	return mem_rw(file, (char __user*)buf, count, ppos, 1);

}



loff_t mem_lseek(struct file *file, loff_t offset, int orig)