extcon: return error code on failure

extcon: return error code on failure

Function get_zeroed_page() returns a NULL pointer if there is no enough
memory. In function extcon_sync(), it returns 0 if the call to
get_zeroed_page() fails. The return value 0 indicates success in the
context, which is incosistent with the execution status. This patch
fixes the bug by returning -ENOMEM.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188611

Signed-off-by: Pan Bian <[email protected]>
Fixes: a580982f0836e
Cc: stable <[email protected]>
Acked-by: Chanwoo Choi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>