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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: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190605194556.16744-1-daniel.vetter@ffwll.ch
alistair/sunxi64-5.4-dsi
Daniel Vetter 2019-06-05 21:45:56 +02:00
parent 1a1e5c0f5b
commit 1882018a70
1 changed files with 3 additions and 2 deletions
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5
drivers/gpu/drm/drm_debugfs_crc.c
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@ -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);