From: Luca Barbieri <luca@luca-barbieri.com>
Date: Sat, 30 Jan 2010 22:21:38 +0000 (+0100)
Subject: drm/nouveau: call ttm_bo_wait with the bo lock held to prevent hang
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f0fbe3eb5f65fe5948219f4ceac68f8a665b1fc6;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

drm/nouveau: call ttm_bo_wait with the bo lock held to prevent hang

nouveau_gem_ioctl_cpu_prep calls ttm_bo_wait without the bo lock held.
ttm_bo_wait unlocks that lock, and so must be called with it held.

Currently this bug causes libdrm nouveau_bo_busy() to hang the machine.

Signed-off-by: Luca Barbieri <luca at luca-barbieri.com>
Acked-by: Maarten Maathuis <madman2003@gmail.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
---

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 6ac804b0c9f9..70cc30803e3b 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -925,7 +925,9 @@ nouveau_gem_ioctl_cpu_prep(struct drm_device *dev, void *data,
 	}
 
 	if (req->flags & NOUVEAU_GEM_CPU_PREP_NOBLOCK) {
+		spin_lock(&nvbo->bo.lock);
 		ret = ttm_bo_wait(&nvbo->bo, false, false, no_wait);
+		spin_unlock(&nvbo->bo.lock);
 	} else {
 		ret = ttm_bo_synccpu_write_grab(&nvbo->bo, no_wait);
 		if (ret == 0)