From: Tim Bird Date: Wed, 8 Feb 2012 02:34:28 +0000 (-0800) Subject: staging: android: logger: clarify non-update of w_off in do_write_log_from_user X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=350a1955957d73352c043d0f948e3f28bb118c57;p=deliverable%2Flinux.git staging: android: logger: clarify non-update of w_off in do_write_log_from_user Add comment to explain when w_off is not updated in case of failed second fragment copy to buffer. Signed-off-by: Tim Bird Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c index 6d92b7ef0a55..0d2367f2c15f 100644 --- a/drivers/staging/android/logger.c +++ b/drivers/staging/android/logger.c @@ -330,6 +330,12 @@ static ssize_t do_write_log_from_user(struct logger_log *log, if (count != len) if (copy_from_user(log->buffer, buf + len, count - len)) + /* + * Note that by not updating w_off, this abandons the + * portion of the new entry that *was* successfully + * copied, just above. This is intentional to avoid + * message corruption from missing fragments. + */ return -EFAULT; log->w_off = logger_offset(log, log->w_off + count);