From: Maarten Lankhorst Date: Tue, 23 Mar 2021 15:50:23 +0000 (+0100) Subject: drm/i915: Add ww locking around vm_access() X-Git-Tag: v5.13-rc1~123^2~10^2~38 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=52665fe7fc20e0c2888416715bb028e398fe3a79;p=linux-platform-drivers-x86.git drm/i915: Add ww locking around vm_access() i915_gem_object_pin_map potentially needs a ww context, so ensure we have one we can revoke. Signed-off-by: Maarten Lankhorst Reviewed-by: Thomas Hellström Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-35-maarten.lankhorst@linux.intel.com --- diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c index 163208a6260d..2561a2f1e54f 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c @@ -421,7 +421,9 @@ vm_access(struct vm_area_struct *area, unsigned long addr, { struct i915_mmap_offset *mmo = area->vm_private_data; struct drm_i915_gem_object *obj = mmo->obj; + struct i915_gem_ww_ctx ww; void *vaddr; + int err = 0; if (i915_gem_object_is_readonly(obj) && write) return -EACCES; @@ -430,10 +432,18 @@ vm_access(struct vm_area_struct *area, unsigned long addr, if (addr >= obj->base.size) return -EINVAL; + i915_gem_ww_ctx_init(&ww, true); +retry: + err = i915_gem_object_lock(obj, &ww); + if (err) + goto out; + /* As this is primarily for debugging, let's focus on simplicity */ vaddr = i915_gem_object_pin_map(obj, I915_MAP_FORCE_WC); - if (IS_ERR(vaddr)) - return PTR_ERR(vaddr); + if (IS_ERR(vaddr)) { + err = PTR_ERR(vaddr); + goto out; + } if (write) { memcpy(vaddr + addr, buf, len); @@ -443,6 +453,16 @@ vm_access(struct vm_area_struct *area, unsigned long addr, } i915_gem_object_unpin_map(obj); +out: + if (err == -EDEADLK) { + err = i915_gem_ww_ctx_backoff(&ww); + if (!err) + goto retry; + } + i915_gem_ww_ctx_fini(&ww); + + if (err) + return err; return len; }