This is a note to let you know that I've just added the patch titled
drm/vmwgfx: Make sure the screen surface is ref counted
to the 6.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-vmwgfx-make-sure-the-screen-surface-is-ref-count.patch
and it can be found in the queue-6.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 93d2e989d74624d7c748780d25075b996d98356e
Author: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
Date: Mon Jul 22 14:41:14 2024 -0400
drm/vmwgfx: Make sure the screen surface is ref counted
[ Upstream commit 09f34a00272d2311f6e5d64ed8ad824ef78f7487 ]
Fix races issues in virtual crc generation by making sure the surface
the code uses for crc computation is properly ref counted.
Crc generation was trying to be too clever by allowing the surfaces
to go in and out of scope, with the hope of always having some kind
of screen present. That's not always the code, in particular during
atomic disable, so to make sure the surface, when present, is not
being actively destroyed at the same time, hold a reference to it.
Signed-off-by: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
Fixes: 7b0062036c3b ("drm/vmwgfx: Implement virtual crc generation")
Cc: Zack Rusin <zack.rusin@xxxxxxxxxxxx>
Cc: Broadcom internal kernel review list <bcm-kernel-feedback-list@xxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Maaz Mombasawala <maaz.mombasawala@xxxxxxxxxxxx>
Reviewed-by: Martin Krastev <martin.krastev@xxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240722184313.181318-3-zack.rusin@xxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_vkms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_vkms.c
index 7e93a45948f79..ac002048d8e5e 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_vkms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_vkms.c
@@ -76,7 +76,7 @@ vmw_surface_sync(struct vmw_private *vmw,
return ret;
}
-static int
+static void
compute_crc(struct drm_crtc *crtc,
struct vmw_surface *surf,
u32 *crc)
@@ -102,8 +102,6 @@ compute_crc(struct drm_crtc *crtc,
}
vmw_bo_unmap(bo);
-
- return 0;
}
static void
@@ -117,7 +115,6 @@ crc_generate_worker(struct work_struct *work)
u64 frame_start, frame_end;
u32 crc32 = 0;
struct vmw_surface *surf = 0;
- int ret;
spin_lock_irq(&du->vkms.crc_state_lock);
crc_pending = du->vkms.crc_pending;
@@ -131,22 +128,24 @@ crc_generate_worker(struct work_struct *work)
return;
spin_lock_irq(&du->vkms.crc_state_lock);
- surf = du->vkms.surface;
+ surf = vmw_surface_reference(du->vkms.surface);
spin_unlock_irq(&du->vkms.crc_state_lock);
- if (vmw_surface_sync(vmw, surf)) {
- drm_warn(crtc->dev, "CRC worker wasn't able to sync the crc surface!\n");
- return;
- }
+ if (surf) {
+ if (vmw_surface_sync(vmw, surf)) {
+ drm_warn(
+ crtc->dev,
+ "CRC worker wasn't able to sync the crc surface!\n");
+ return;
+ }
- ret = compute_crc(crtc, surf, &crc32);
- if (ret)
- return;
+ compute_crc(crtc, surf, &crc32);
+ vmw_surface_unreference(&surf);
+ }
spin_lock_irq(&du->vkms.crc_state_lock);
frame_start = du->vkms.frame_start;
frame_end = du->vkms.frame_end;
- crc_pending = du->vkms.crc_pending;
du->vkms.frame_start = 0;
du->vkms.frame_end = 0;
du->vkms.crc_pending = false;
@@ -165,7 +164,7 @@ vmw_vkms_vblank_simulate(struct hrtimer *timer)
struct vmw_display_unit *du = container_of(timer, struct vmw_display_unit, vkms.timer);
struct drm_crtc *crtc = &du->crtc;
struct vmw_private *vmw = vmw_priv(crtc->dev);
- struct vmw_surface *surf = NULL;
+ bool has_surface = false;
u64 ret_overrun;
bool locked, ret;
@@ -180,10 +179,10 @@ vmw_vkms_vblank_simulate(struct hrtimer *timer)
WARN_ON(!ret);
if (!locked)
return HRTIMER_RESTART;
- surf = du->vkms.surface;
+ has_surface = du->vkms.surface != NULL;
vmw_vkms_unlock(crtc);
- if (du->vkms.crc_enabled && surf) {
+ if (du->vkms.crc_enabled && has_surface) {
u64 frame = drm_crtc_accurate_vblank_count(crtc);
spin_lock(&du->vkms.crc_state_lock);
@@ -337,6 +336,8 @@ vmw_vkms_crtc_cleanup(struct drm_crtc *crtc)
{
struct vmw_display_unit *du = vmw_crtc_to_du(crtc);
+ if (du->vkms.surface)
+ vmw_surface_unreference(&du->vkms.surface);
WARN_ON(work_pending(&du->vkms.crc_generator_work));
hrtimer_cancel(&du->vkms.timer);
}
@@ -498,9 +499,12 @@ vmw_vkms_set_crc_surface(struct drm_crtc *crtc,
struct vmw_display_unit *du = vmw_crtc_to_du(crtc);
struct vmw_private *vmw = vmw_priv(crtc->dev);
- if (vmw->vkms_enabled) {
+ if (vmw->vkms_enabled && du->vkms.surface != surf) {
WARN_ON(atomic_read(&du->vkms.atomic_lock) != VMW_VKMS_LOCK_MODESET);
- du->vkms.surface = surf;
+ if (du->vkms.surface)
+ vmw_surface_unreference(&du->vkms.surface);
+ if (surf)
+ du->vkms.surface = vmw_surface_reference(surf);
}
}
