Commit 6d0bfef7 authored by Dmitry Osipenko's avatar Dmitry Osipenko

drm/gem-vram: Fix deadlock in drm_gem_vram_vmap()

Recently DRM framebuffer core and all drivers were moved to unlocked
vmapping functions that take the reservation lock. The drm_gem_vram_vmap()
was missed out by accident and now deadlocks drivers that use drm_gem_vram
helpers when framebuffer is updated, like Bochs driver. Remove the locking
from drm_gem_vram_v[un]map() functions to fix the deadlock.
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Fixes: 79e2cf2e ("drm/gem: Take reservation lock for vmap/vunmap operations")
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221113233850.427704-1-dmitry.osipenko@collabora.com
parent b1d39f0f
...@@ -433,25 +433,19 @@ int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct iosys_map *map) ...@@ -433,25 +433,19 @@ int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct iosys_map *map)
{ {
int ret; int ret;
ret = ttm_bo_reserve(&gbo->bo, true, false, NULL); dma_resv_assert_held(gbo->bo.base.resv);
if (ret)
return ret;
ret = drm_gem_vram_pin_locked(gbo, 0); ret = drm_gem_vram_pin_locked(gbo, 0);
if (ret) if (ret)
goto err_ttm_bo_unreserve; return ret;
ret = drm_gem_vram_kmap_locked(gbo, map); ret = drm_gem_vram_kmap_locked(gbo, map);
if (ret) if (ret)
goto err_drm_gem_vram_unpin_locked; goto err_drm_gem_vram_unpin_locked;
ttm_bo_unreserve(&gbo->bo);
return 0; return 0;
err_drm_gem_vram_unpin_locked: err_drm_gem_vram_unpin_locked:
drm_gem_vram_unpin_locked(gbo); drm_gem_vram_unpin_locked(gbo);
err_ttm_bo_unreserve:
ttm_bo_unreserve(&gbo->bo);
return ret; return ret;
} }
EXPORT_SYMBOL(drm_gem_vram_vmap); EXPORT_SYMBOL(drm_gem_vram_vmap);
...@@ -467,16 +461,10 @@ EXPORT_SYMBOL(drm_gem_vram_vmap); ...@@ -467,16 +461,10 @@ EXPORT_SYMBOL(drm_gem_vram_vmap);
void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo, void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo,
struct iosys_map *map) struct iosys_map *map)
{ {
int ret; dma_resv_assert_held(gbo->bo.base.resv);
ret = ttm_bo_reserve(&gbo->bo, false, false, NULL);
if (WARN_ONCE(ret, "ttm_bo_reserve_failed(): ret=%d\n", ret))
return;
drm_gem_vram_kunmap_locked(gbo, map); drm_gem_vram_kunmap_locked(gbo, map);
drm_gem_vram_unpin_locked(gbo); drm_gem_vram_unpin_locked(gbo);
ttm_bo_unreserve(&gbo->bo);
} }
EXPORT_SYMBOL(drm_gem_vram_vunmap); EXPORT_SYMBOL(drm_gem_vram_vunmap);
......
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