From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Dmitry V. Levin" <ldv@altlinux.org>
Subject: Re: [PATCH v4 4/5] drm: Add decoding of i915 ioctls
Date: Tue, 8 Sep 2015 04:30:52 +0300
Message-ID: <20150908013052.GC17781@altlinux.org>
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On Tue, Sep 08, 2015 at 04:18:11AM +0300, Dmitry V. Levin wrote:
[...]
> So the whole function should look smth like this:
>=20
> static int i915_getparam(struct tcb *tcp, const unsigned int code, long a=
rg)
> {
> 	struct drm_i915_getparam param;
>=20
> 	if (entering(tcp)) {
> 		if (umove_or_printaddr(tcp, arg, &param))
> 			return RVAL_DECODED | 1;
> 		tprints(", {param=3D");

or rather
		tprints(", ");
		if (umove_or_printaddr(tcp, arg, &param))
			return RVAL_DECODED | 1;
		tprints("{param=3D");


> In this and other functions I slightly prefer
> 	if (umove_or_printaddr(tcp, arg, &param))
> 		return RVAL_DECODED | 1;
> over your variant because umove_or_printaddr() handles NULL address
> and !verbose(tcp) case better.

And the whole function will look as simple as this:

static int i915_setparam(struct tcb *tcp, const unsigned int code, long arg)
{
 	struct drm_i915_setparam param;

	tprints(", ");
	if (!umove_or_printaddr(tcp, arg, &param)) {
		tprints("{param=3D");
		printxval(drm_i915_setparams, param.param, "I915_PARAM_???");
		tprintf(", value=3D%d}", param.value);
	}

	return RVAL_DECODED | 1;
}

Note the absence of entering(tcp) check because this DRM_IOW parser always
returns a value with RVAL_DECODED flag set.


--=20
ldv

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