[PATCH] kmsg_write: don't return printk return value
kmsg_write returns with printk, so some programs may be confused by a
successful write() with a return value different than the buffer length.
# /bin/echo something > /dev/kmsg
/bin/echo: write error: Inappropriate ioctl for device
The drawbacks is that the printk return value can no more be quickly
checked from userspace.
Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 91dd669..a85f3a3 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -817,7 +817,7 @@
size_t count, loff_t *ppos)
{
char *tmp;
- int ret;
+ ssize_t ret;
tmp = kmalloc(count + 1, GFP_KERNEL);
if (tmp == NULL)
@@ -826,6 +826,9 @@
if (!copy_from_user(tmp, buf, count)) {
tmp[count] = 0;
ret = printk("%s", tmp);
+ if (ret > count)
+ /* printk can add a prefix */
+ ret = count;
}
kfree(tmp);
return ret;