linux-kernel - [PATCH 1/5] drm/vblank: Use spin_(un)lock_irq() in drm_crtc_vblank

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:   Mon, 20 Jul 2020 15:07:32 -0400
From:   Lyude Paul <lyude@...hat.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Daniel Vetter <daniel@...ll.ch>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 1/5] drm/vblank: Use spin_(un)lock_irq() in drm_crtc_vblank_reset()

All of the drivers in the kernel tree only call this from one of the
following contexts:

* drm_crtc_funcs->reset
* During initial module load

Since both of these contexts are guaranteed to have interrupts enabled
beforehand, there's no need to use the irqsave/irqrestore variants of
spin_(un)lock(). So, fix this to make the irq context of this function
more obvious.

Signed-off-by: Lyude Paul <lyude@...hat.com>
Cc: Daniel Vetter <daniel@...ll.ch>
---
 drivers/gpu/drm/drm_vblank.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index f402c75b9d343..6af78aecea9d4 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -1363,11 +1363,10 @@ EXPORT_SYMBOL(drm_crtc_vblank_off);
 void drm_crtc_vblank_reset(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
-	unsigned long irqflags;
 	unsigned int pipe = drm_crtc_index(crtc);
 	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 
-	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	spin_lock_irq(&dev->vbl_lock);
 	/*
 	 * Prevent subsequent drm_vblank_get() from enabling the vblank
 	 * interrupt by bumping the refcount.
@@ -1376,7 +1375,7 @@ void drm_crtc_vblank_reset(struct drm_crtc *crtc)
 		atomic_inc(&vblank->refcount);
 		vblank->inmodeset = 1;
 	}
-	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+	spin_unlock_irq(&dev->vbl_lock);
 
 	drm_WARN_ON(dev, !list_empty(&dev->vblank_event_list));
 	drm_WARN_ON(dev, !list_empty(&vblank->pending_work));
-- 
2.26.2