linux-kernel - [PATCH 3/5] i915 compat ioctl(): just use drm_ioctl

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Date:   Fri, 29 May 2020 01:41:43 +0100
From:   Al Viro <viro@...IV.linux.org.uk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        Jani Nikula <jani.nikula@...ux.intel.com>
Subject: [PATCH 3/5] i915 compat ioctl(): just use drm_ioctl_kernel()

From: Al Viro <viro@...iv.linux.org.uk>

compat_alloc_user_space() is a bad kludge; the sooner it goes, the
better...

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 drivers/gpu/drm/i915/i915_ioc32.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_ioc32.c b/drivers/gpu/drm/i915/i915_ioc32.c
index 8e45ca3d2ede..55b97c3a3dde 100644
--- a/drivers/gpu/drm/i915/i915_ioc32.c
+++ b/drivers/gpu/drm/i915/i915_ioc32.c
@@ -47,20 +47,16 @@ static int compat_i915_getparam(struct file *file, unsigned int cmd,
 				unsigned long arg)
 {
 	struct drm_i915_getparam32 req32;
-	drm_i915_getparam_t __user *request;
+	struct drm_i915_getparam req;
 
 	if (copy_from_user(&req32, (void __user *)arg, sizeof(req32)))
 		return -EFAULT;
 
-	request = compat_alloc_user_space(sizeof(*request));
-	if (!access_ok(request, sizeof(*request)) ||
-	    __put_user(req32.param, &request->param) ||
-	    __put_user((void __user *)(unsigned long)req32.value,
-		       &request->value))
-		return -EFAULT;
+	req.param = req32.param;
+	req.value = compat_ptr(req32.value);
 
-	return drm_ioctl(file, DRM_IOCTL_I915_GETPARAM,
-			 (unsigned long)request);
+	return drm_ioctl_kernel(file, i915_getparam_ioctl, &req,
+				DRM_RENDER_ALLOW);
 }
 
 static drm_ioctl_compat_t *i915_compat_ioctls[] = {
-- 
2.11.0