From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 68A6A828DF for ; Fri, 29 Jan 2016 13:17:21 -0500 (EST) Received: by mail-pa0-f47.google.com with SMTP id ho8so45051844pac.2 for ; Fri, 29 Jan 2016 10:17:21 -0800 (PST) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTP id we3si3530534pab.52.2016.01.29.10.17.04 for ; Fri, 29 Jan 2016 10:17:04 -0800 (PST) Subject: [PATCH 15/31] mm: factor out VMA fault permission checking From: Dave Hansen Date: Fri, 29 Jan 2016 10:17:03 -0800 References: <20160129181642.98E7D468@viggo.jf.intel.com> In-Reply-To: <20160129181642.98E7D468@viggo.jf.intel.com> Message-Id: <20160129181703.02114D45@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, torvalds@linux-foundation.org, Dave Hansen , dave.hansen@linux.intel.com From: Dave Hansen This code matches a fault condition up with the VMA and ensures that the VMA allows the fault to be handled instead of just erroring out. We will be extending this in a moment to comprehend protection keys. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner --- b/mm/gup.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff -puN mm/gup.c~pkeys-10-pte-fault mm/gup.c --- a/mm/gup.c~pkeys-10-pte-fault 2016-01-28 15:52:22.856518359 -0800 +++ b/mm/gup.c 2016-01-28 15:52:22.860518543 -0800 @@ -611,6 +611,18 @@ next_page: } EXPORT_SYMBOL(__get_user_pages); +bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) +{ + vm_flags_t vm_flags; + + vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; + + if (!(vm_flags & vma->vm_flags)) + return false; + + return true; +} + /* * fixup_user_fault() - manually resolve a user page fault * @tsk: the task_struct to use for page fault accounting, or @@ -646,7 +658,6 @@ int fixup_user_fault(struct task_struct bool *unlocked) { struct vm_area_struct *vma; - vm_flags_t vm_flags; int ret, major = 0; if (unlocked) @@ -657,8 +668,7 @@ retry: if (!vma || address < vma->vm_start) return -EFAULT; - vm_flags = (fault_flags & FAULT_FLAG_WRITE) ? VM_WRITE : VM_READ; - if (!(vm_flags & vma->vm_flags)) + if (!vma_permits_fault(vma, fault_flags)) return -EFAULT; ret = handle_mm_fault(mm, vma, address, fault_flags); _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org