From 1882018a70e06376234133e69ede9dd743b4dbd9 Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Wed, 5 Jun 2019 21:45:56 +0200
Subject: [PATCH] drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry
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Git-commit: 1882018a70e06376234133e69ede9dd743b4dbd9
Patch-mainline: v5.3-rc1
References: bsc#1051510
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
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/drm_debugfs_crc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/drm_debugfs_crc.c
+++ b/drivers/gpu/drm/drm_debugfs_crc.c
@@ -343,8 +343,9 @@ int drm_crtc_add_crc_entry(struct drm_cr
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) {
@@ -369,7 +370,7 @@ int drm_crtc_add_crc_entry(struct drm_cr
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);