From a6d65e451cc4e7127698384868a4447ee7be7d16 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 16 Oct 2017 21:27:32 +0100 Subject: [PATCH] drm/i915: Report -EFAULT before pwrite fast path into shmemfs When pwriting into shmemfs, the fast path pagecache_write does not notice when it is writing to beyond the end of the truncated shmemfs inode. Report -EFAULT directly when we try to use pwrite into the !I915_MADV_WILLNEED object. Fixes: 7c55e2c5772d ("drm/i915: Use pagecache write to prepopulate shmemfs from pwrite-ioctl") Testcase: igt/gem_madvise/dontneed-before-pwrite Signed-off-by: Chris Wilson Cc: Matthew Auld Cc: Joonas Lahtinen Cc: Mika Kuoppala Reviewed-by: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20171016202732.25459-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index ee2a30422020..d699ea3ab80b 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2730,6 +2730,9 @@ i915_gem_object_pwrite_gtt(struct drm_i915_gem_object *obj, if (i915_gem_object_has_pages(obj)) return -ENODEV; + if (obj->mm.madv != I915_MADV_WILLNEED) + return -EFAULT; + /* Before the pages are instantiated the object is treated as being * in the CPU domain. The pages will be clflushed as required before * use, and we can freely write into the pages directly. If userspace