Commit 034089b6 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Greg Kroah-Hartman

proc: unify mem_read() and mem_write()

commit 572d34b9 upstream.

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.
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3a196fbe
...@@ -782,57 +782,13 @@ static int mem_open(struct inode* inode, struct file* file) ...@@ -782,57 +782,13 @@ static int mem_open(struct inode* inode, struct file* file)
return 0; return 0;
} }
static ssize_t mem_read(struct file * file, char __user * buf, static ssize_t mem_rw(struct file *file, char __user *buf,
size_t count, loff_t *ppos) size_t count, loff_t *ppos, int write)
{ {
int ret;
char *page;
unsigned long src = *ppos;
struct mm_struct *mm = file->private_data; struct mm_struct *mm = file->private_data;
unsigned long addr = *ppos;
if (!mm) ssize_t copied;
return 0;
page = (char *)__get_free_page(GFP_TEMPORARY);
if (!page)
return -ENOMEM;
ret = 0;
while (count > 0) {
int this_len, retval;
this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
retval = access_remote_vm(mm, src, page, this_len, 0);
if (!retval) {
if (!ret)
ret = -EIO;
break;
}
if (copy_to_user(buf, page, retval)) {
ret = -EFAULT;
break;
}
ret += retval;
src += retval;
buf += retval;
count -= retval;
}
*ppos = src;
free_page((unsigned long) page);
return ret;
}
static ssize_t mem_write(struct file * file, const char __user *buf,
size_t count, loff_t *ppos)
{
int copied;
char *page; char *page;
unsigned long dst = *ppos;
struct mm_struct *mm = file->private_data;
if (!mm) if (!mm)
return 0; return 0;
...@@ -843,30 +799,48 @@ static ssize_t mem_write(struct file * file, const char __user *buf, ...@@ -843,30 +799,48 @@ static ssize_t mem_write(struct file * file, const char __user *buf,
copied = 0; copied = 0;
while (count > 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; if (write && copy_from_user(page, buf, this_len)) {
if (copy_from_user(page, buf, this_len)) {
copied = -EFAULT; copied = -EFAULT;
break; break;
} }
retval = access_remote_vm(mm, dst, page, this_len, 1);
if (!retval) { this_len = access_remote_vm(mm, addr, page, this_len, write);
if (!this_len) {
if (!copied) if (!copied)
copied = -EIO; copied = -EIO;
break; break;
} }
copied += retval;
buf += retval; if (!write && copy_to_user(buf, page, this_len)) {
dst += retval; copied = -EFAULT;
count -= retval; break;
}
buf += this_len;
addr += this_len;
copied += this_len;
count -= this_len;
} }
*ppos = dst; *ppos = addr;
free_page((unsigned long) page); free_page((unsigned long) page);
return copied; return copied;
} }
static ssize_t mem_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
return mem_rw(file, buf, count, ppos, 0);
}
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) loff_t mem_lseek(struct file *file, loff_t offset, int orig)
{ {
switch (orig) { switch (orig) {
......
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