drm/i915: Attempt to prefault user pages for pread/pwrite
... in the hope that it makes the atomic fast paths more likely.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 942e4b3..b44c09a 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -265,19 +265,14 @@
char __user *data,
int length)
{
- char __iomem *vaddr;
int unwritten;
+ char *vaddr;
vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);
- if (vaddr == NULL)
- return -ENOMEM;
unwritten = __copy_to_user_inatomic(data, vaddr + page_offset, length);
kunmap_atomic(vaddr, KM_USER0);
- if (unwritten)
- return -EFAULT;
-
- return 0;
+ return unwritten ? -EFAULT : 0;
}
static int i915_gem_object_needs_bit17_swizzle(struct drm_gem_object *obj)
@@ -602,6 +597,13 @@
goto out;
}
+ ret = fault_in_pages_writeable((char __user *)(uintptr_t)args->data_ptr,
+ args->size);
+ if (ret) {
+ ret = -EFAULT;
+ goto out;
+ }
+
if (i915_gem_object_needs_bit17_swizzle(obj)) {
ret = i915_gem_shmem_pread_slow(dev, obj, args, file_priv);
} else {
@@ -668,18 +670,14 @@
char __user *data,
int length)
{
- char __iomem *vaddr;
- unsigned long unwritten;
+ int unwritten;
+ char *vaddr;
vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);
- if (vaddr == NULL)
- return -ENOMEM;
unwritten = __copy_from_user_inatomic(vaddr + page_offset, data, length);
kunmap_atomic(vaddr, KM_USER0);
- if (unwritten)
- return -EFAULT;
- return 0;
+ return unwritten ? -EFAULT : 0;
}
/**
@@ -1078,6 +1076,13 @@
goto out;
}
+ ret = fault_in_pages_readable((char __user *)(uintptr_t)args->data_ptr,
+ args->size);
+ if (ret) {
+ ret = -EFAULT;
+ goto out;
+ }
+
/* We can only do the GTT pwrite on untiled buffers, as otherwise
* it would end up going through the fenced access, and we'll get
* different detiling behavior between reading and writing.