From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: [PATCH 2/2] drm/i915: properly prefault for pread/pwrite Date: Thu, 17 Nov 2011 12:52:45 -0800 Message-ID: References: <1317203844-2930-1-git-send-email-daniel.vetter@ffwll.ch> <1317203844-2930-2-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0953802630==" Return-path: Received: from keithp.com (home.keithp.com [63.227.221.253]) by gabe.freedesktop.org (Postfix) with ESMTP id C5AC09E776 for ; Thu, 17 Nov 2011 12:52:49 -0800 (PST) In-Reply-To: <1317203844-2930-2-git-send-email-daniel.vetter@ffwll.ch> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx Cc: Daniel Vetter List-Id: intel-gfx@lists.freedesktop.org --===============0953802630== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable On Wed, 28 Sep 2011 11:57:24 +0200, Daniel Vetter = wrote: > + char __user *end =3D uaddr + size - 1; ... > + if (ret =3D=3D 0) { > + if (((unsigned long)uaddr & PAGE_MASK) !=3D > + ((unsigned long)end & PAGE_MASK)) > + ret =3D __put_user(0, end); > + } This is wrong -- if size =3D=3D PAGE_SIZE, then we'll be doing an extra write at 'end' every time (and, I imagine that's a common case). And, you mentioned a 'better' fix? =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUBTsV0HTYtFsjWk68qAQh3nhAApUqRTWKE7HlyLM7AZQK9sH35WNdDBrmj EZhslb0fyznfeiG2LJlllKN4I6+oWAJsaESoTZtHZ438skCU/iVSYis06CX6snlN pPDZ673M3g60KodVd7aVAHUSUpHZKG/w3jBOHzr+LIEYkAC439l97K9QzF9O5DsX ip/yAKB0co1k+dR8t+7r275PnSfZnrEe2P0i1K4/LPk5YwcotE4PpUoFN1atRhnN 1vWY7BCylXx81dq4MwRJRQjV0GDDyHWz/zTHCaImOc8596R1TA2N7/Eyam+XuZQH rtipDAWvEk6h+Lmq5YJ0ySk9ofZCcVfLOIKNbvYdh0Ufx3IPp/G4zUcWiWDfZD7K Rnk13Bp7PU6iwceIBypKcHJH6P3sGEoMOgwypNG5yUQxqqWqawthQJzc9ye1TV65 aBmUTbtMb4O5+S0GgRKaO0PaCgeQdjc+HAb1BzDh90IPwCmKVzBsyrCBBbe3Pg7k mqpj4CYR9IW1xHh4ztD3RG9bh5LYNWu5IYpAY8GdA/oiRQHRXajc2DN68rAyFUEr mAFmkppQxvzRdO7nU5kr5pttgwNF4ke17ZjVHJHde9jUy+vJCySdAkfnrZMznZ54 B5diw/pZ/iI3cN0ZTnD7v5XzgOjDwTSQwWirIFS9gdqG3Q4oiMKNx6mjt0JJnzpp LpeMVGA71Dw= =3YfM -----END PGP SIGNATURE----- --=-=-=-- --===============0953802630== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx --===============0953802630==--