From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261576AbVBHOcr (ORCPT ); Tue, 8 Feb 2005 09:32:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261569AbVBHOce (ORCPT ); Tue, 8 Feb 2005 09:32:34 -0500 Received: from mx1.redhat.com ([66.187.233.31]:57283 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S261568AbVBHOcO (ORCPT ); Tue, 8 Feb 2005 09:32:14 -0500 From: David Howells To: torvalds@osdl.org, akpm@osdl.org cc: linux-kernel@vger.kernel.org, uclinux-dev@uclinux.org Subject: [PATCH] NOMMU: Improved handling of get_unmapped_area() errors X-Mailer: MH-E 7.82; nmh 1.0.4; GNU Emacs 21.3.50.1 Date: Tue, 08 Feb 2005 14:32:05 +0000 Message-ID: <19277.1107873125@redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The attached patch does two things: (1) We no longer check the return value of file->f_op->get_unmapped_area() unless we actually called it. We know addr is zero otherwise because we'd've given an error earlier if it wasn't. (2) If -ENOSYS was returned by that operation, then we assume we actually called a driver (such as the framebuffer driver) that might want to invoke the operation in a lower level driver (such as matroxfb) if one exists, and that it found that one didn't. We translate the -ENOSYS error into -ENODEV - the error we would have given if the operation was not supplied in the file ops. Doing this permits us an opportunity for arch_get_unmapped_area() or something else to be called if we want that to happen, particularly in the MMU case. Signed-Off-By: David Howells --- warthog>diffstat -p1 nommu-2611rc3.diff mm/nommu.c | 12 +++++++----- 1 files changed, 7 insertions(+), 5 deletions(-) diff -uNrp /warthog/kernels/linux-2.6.11-rc3/mm/nommu.c linux-2.6.11-rc3-frv/mm/nommu.c --- /warthog/kernels/linux-2.6.11-rc3/mm/nommu.c 2005-02-04 11:50:28.000000000 +0000 +++ linux-2.6.11-rc3-frv/mm/nommu.c 2005-02-08 13:54:18.816577889 +0000 @@ -567,12 +567,14 @@ unsigned long do_mmap_pgoff(struct file * that it represents a valid section of the address space * - this is the hook for quasi-memory character devices */ - if (file && file->f_op->get_unmapped_area) + if (file && file->f_op->get_unmapped_area) { addr = file->f_op->get_unmapped_area(file, addr, len, pgoff, flags); - - if (IS_ERR((void *) addr)) { - ret = addr; - goto error; + if (IS_ERR((void *) addr)) { + ret = addr; + if (ret == (unsigned long) -ENOSYS) + ret = (unsigned long) -ENODEV; + goto error; + } } /* we're going to need a VMA struct as well */