proc_dointvec: write a single value

The commit 00b7c3395aec3df43de5bd02a3c5a099ca51169f
"sysctl: refactor integer handling proc code"
modified the behaviour of writing to /proc.
Before the commit, write("1\n") to /proc/sys/kernel/printk succeeded. But
now it returns EINVAL.

This commit supports writing a single value to a multi-valued entry.

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Reviewed-and-tested-by: WANG Cong <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b12583047757..f948f20f09cb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2253,6 +2253,8 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
                 if (write) {
                         left -= proc_skip_spaces(&kbuf);
 
+                        if (!left)
+                                break;
                         err = proc_get_long(&kbuf, &left, &lval, &neg,
                                              proc_wspace_sep,
                                              sizeof(proc_wspace_sep), NULL);
@@ -2279,7 +2281,7 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
 
         if (!write && !first && left && !err)
                 err = proc_put_char(&buffer, &left, '\n');
-        if (write && !err)
+        if (write && !err && left)
                 left -= proc_skip_spaces(&kbuf);
 free:
         if (write) {