[PATCH] HID: hidraw: fix nonblock read return EAGAIN after device removed
From: founder.fang <hidden>
Date: 2012-11-21 07:20:33
Also in:
lkml
when nonblock read the condition check (file->f_flags & O_NONBLOCK) always be true, signal_pending and device exist checking never get a chance to run, so the user mode code always get EAGAIN even if device removed. move nonblock mode checking to the last can fix this problem. Signed-off-by: Founder Fang <redacted>
--- hid-git/drivers/hid/hidraw.c.orig 2012-11-21 14:37:04.977106383 +0800
+++ hid-git/drivers/hid/hidraw.c 2012-11-21 14:40:35.882152200 +0800@@ -57,10 +57,6 @@ static ssize_t hidraw_read(struct file * set_current_state(TASK_INTERRUPTIBLE); while (list->head == list->tail) { - if (file->f_flags & O_NONBLOCK) { - ret = -EAGAIN; - break; - } if (signal_pending(current)) { ret = -ERESTARTSYS; break;
@@ -69,6 +65,10 @@ static ssize_t hidraw_read(struct file * ret = -EIO; break; } + if (file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + break; + } /* allow O_NONBLOCK to work well from other threads */ mutex_unlock(&list->read_mutex);