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Commit 1882018a authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry 



We can be called from any context, we need to be prepared.

Noticed this while hacking on vkms, which calls this function from a
normal worker. Which really upsets lockdep.

Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Emil Velikov <emil.velikov@collabora.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: default avatarBenjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190605194556.16744-1-daniel.vetter@ffwll.ch
parent 1a1e5c0f

drivers/gpu/drm/drm_debugfs_crc.c

+3 −2
Original line number Diff line number Diff line
@@ -396,8 +396,9 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 
	struct drm_crtc_crc *crc = &crtc->crc;

	struct drm_crtc_crc_entry *entry;

	int head, tail;

	unsigned long flags;



	spin_lock(&crc->lock);

	spin_lock_irqsave(&crc->lock, flags);



	/* Caller may not have noticed yet that userspace has stopped reading */

	if (!crc->entries) {
@@ -428,7 +429,7 @@ int drm_crtc_add_crc_entry(struct drm_crtc *crtc, bool has_frame, 
	head = (head + 1) & (DRM_CRC_ENTRIES_NR - 1);

	crc->head = head;



	spin_unlock(&crc->lock);

	spin_unlock_irqrestore(&crc->lock, flags);



	wake_up_interruptible(&crc->wq);