From: Davidlohr Bueso <dave@stgolabs.net>
To: oneukum@suse.com
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
dave@stgolabs.net, Davidlohr Bueso <dbueso@suse.de>
Subject: [PATCH 7/8] usb, cdc-acm: optimize barrier usage for Rmw atomic bitops
Date: Wed, 29 Jan 2020 10:15:45 -0800 [thread overview]
Message-ID: <20200129181545.25302-1-dave@stgolabs.net> (raw)
We can avoid the unnecessary barrier on non LL/SC architectures,
such as x86. Instead, use the smp_mb__after_atomic() call.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
drivers/usb/class/cdc-acm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 62f4fb9b362f..0bc4b558f387 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -842,7 +842,7 @@ static void acm_tty_unthrottle(struct tty_struct *tty)
clear_bit(ACM_THROTTLED, &acm->flags);
/* Matches the smp_mb__after_atomic() in acm_read_bulk_callback(). */
- smp_mb();
+ smp_mb__after_atomic();
acm_submit_read_urbs(acm, GFP_KERNEL);
}
--
2.16.4
next reply other threads:[~2020-01-29 18:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 18:15 Davidlohr Bueso [this message]
2020-01-30 10:06 ` [PATCH 7/8] usb, cdc-acm: optimize barrier usage for Rmw atomic bitops Johan Hovold
2020-03-23 17:29 ` Davidlohr Bueso
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