From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 07EF6C433FE for ; Sun, 6 Mar 2022 03:52:25 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 72CC310EB55; Sun, 6 Mar 2022 03:52:25 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by gabe.freedesktop.org (Postfix) with ESMTPS id 281A310EB59; Sun, 6 Mar 2022 03:52:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=9sW6PT9UhN7TdCknrB4vEZzr80Evyo9BiN2TBCQrpu8=; b=mexz5CF+uqowjqVXolKHAmICBZ /gBgallofA7ozgz6jmmxeLDOiLP+ug6bK856a/z+a9w7TUyxkvWlRyWXibD8YaVX9xEhWkvXfvJ0c T9CsFtuhgdywtjyO5X9YgUt7T7PWomuTwyfHCOGFUDiGUHpzGsSie9GdiLq7+5D36BobFZ/yP2NUj qr1wqTzCzqTn0g1ebz0/mAsEBexkspvGujBr22b3rqg8CDfMkfi2+IvRyah//kltQsrveMxB400WD J0XLKsOaVBufmV3UVpDkBZF539qZ0MxKfcyCwprq0N/9p+ZQ6jqDwbiBbdFzFrSEzsOcI1kPbIRAL xGmlkpYw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nQhwK-00E56f-PJ; Sun, 06 Mar 2022 03:52:12 +0000 Date: Sun, 6 Mar 2022 03:52:12 +0000 From: Matthew Wilcox To: Jarkko Sakkinen Message-ID: References: <20220306021534.83553-1-jarkko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Intel-gfx] [PATCH RFC] mm: Add f_ops->populate() X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nathaniel McCallum , linux-unionfs@vger.kernel.org, intel-gfx@lists.freedesktop.org, Dave Hansen , linux-mips@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Reinette Chatre , codalist@coda.cs.cmu.edu, linux-sgx@vger.kernel.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Sun, Mar 06, 2022 at 05:21:11AM +0200, Jarkko Sakkinen wrote: > On Sun, Mar 06, 2022 at 02:57:55AM +0000, Matthew Wilcox wrote: > > On Sun, Mar 06, 2022 at 04:15:33AM +0200, Jarkko Sakkinen wrote: > > > Sometimes you might want to use MAP_POPULATE to ask a device driver to > > > initialize the device memory in some specific manner. SGX driver can use > > > this to request more memory by issuing ENCLS[EAUG] x86 opcode for each > > > page in the address range. > > > > > > Add f_ops->populate() with the same parameters as f_ops->mmap() and make > > > it conditionally called inside call_mmap(). Update call sites > > > accodingly. > > > > Your device driver has a ->mmap operation. Why does it need another > > one? More explanation required here. > > f_ops->mmap() would require an additional parameter, which results > heavy refactoring. > > struct file_operations has 1125 references in the kernel tree, so I > decided to check this way around first. Are you saying that your device driver behaves differently if MAP_POPULATE is set versus if it isn't? That seems hideously broken.