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Subject[PATCH] adjust /dev/{kmem,mem,port} write handlers
The /dev/mem and /dev/kmem write handlers weren't fully POSIX compliant in
that they wouldn't always force the file pointer to be updated when returning
success status.
The /dev/port write handler was inconsistent with the /dev/mem and /dev/kmem
handlers in that when encountering a -EFAULT condition after already having
written a number of items it would return -EFAULT rather than the number of
bytes written.

Signed-Off-By: Jan Beulich <jbeulich@novell.com>

diff -Npru /home/jbeulich/tmp/linux-2.6.16-rc5/drivers/char/mem.c 2.6.16-rc5-posix-dev-mem/drivers/char/mem.c
--- /home/jbeulich/tmp/linux-2.6.16-rc5/drivers/char/mem.c 2006-03-03 09:55:50.000000000 +0100
+++ 2.6.16-rc5-posix-dev-mem/drivers/char/mem.c 2006-03-02 11:45:28.000000000 +0100
@@ -216,11 +216,9 @@ static ssize_t write_mem(struct file * f

copied = copy_from_user(ptr, buf, sz);
if (copied) {
- ssize_t ret;
-
- ret = written + (sz - copied);
- if (ret)
- return ret;
+ written += sz - copied;
+ if (written)
+ break;
return -EFAULT;
}
buf += sz;
@@ -456,11 +454,9 @@ do_write_kmem(void *p, unsigned long rea

copied = copy_from_user(ptr, buf, sz);
if (copied) {
- ssize_t ret;
-
- ret = written + (sz - copied);
- if (ret)
- return ret;
+ written += sz - copied;
+ if (written)
+ break;
return -EFAULT;
}
buf += sz;
@@ -514,11 +510,10 @@ static ssize_t write_kmem(struct file *
if (len) {
written = copy_from_user(kbuf, buf, len);
if (written) {
- ssize_t ret;
-
+ if (wrote + virtr)
+ break;
free_page((unsigned long)kbuf);
- ret = wrote + virtr + (len - written);
- return ret ? ret : -EFAULT;
+ return -EFAULT;
}
}
len = vwrite(kbuf, (char *)p, len);
@@ -563,8 +558,11 @@ static ssize_t write_port(struct file *
return -EFAULT;
while (count-- > 0 && i < 65536) {
char c;
- if (__get_user(c, tmp))
+ if (__get_user(c, tmp)) {
+ if (tmp > buf)
+ break;
return -EFAULT;
+ }
outb(c,i);
i++;
tmp++;
-
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