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 X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE138C32789 for ; Tue, 6 Nov 2018 07:46:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6977820862 for ; Tue, 6 Nov 2018 07:46:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VHrUCI/q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6977820862 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729814AbeKFRKB (ORCPT ); Tue, 6 Nov 2018 12:10:01 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:35085 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729160AbeKFRKA (ORCPT ); Tue, 6 Nov 2018 12:10:00 -0500 Received: by mail-pl1-f195.google.com with SMTP id n4-v6so5784728plp.2 for ; Mon, 05 Nov 2018 23:46:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=LoPekBv4ecKgNNEo5tW7CAeKBEcSexsyyurwBOBdMEw=; b=VHrUCI/qHIB6awukFBbx6Ej+M+JEpfrSip7vIcOekvVO9a5ITIV55GRLl8iR84CKhU wND1OKDQ4MIZythqmUOs6VTTN7ZQ93lQUGLfzvBfdgN9wAHGxgF6FIHfrlsJLlIke715 ayZOJrSJb/KGn/3JMrHXApnglwbqh+MeBfpVMlZO/KGPJEEtWFd5vpV69P0iWXGzOgnx cNs1vKE1nwGPiDyRoUWBM7FERjxn5DCmLyIfC8xfS5nnggRPIVWqvaYYtIrjeP+FqjK7 CfEg6mvwi9m1V1Jrq8eZcOPDOU77yxD4nSHTDErf/LBWBcTOGLpA6lHjitzFS3eEQrDP 0sMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=LoPekBv4ecKgNNEo5tW7CAeKBEcSexsyyurwBOBdMEw=; b=ou/1wFF4fitF3YeBsnUmGSOvO28j/EBxIAE6MZ8nz1K9IndyOskI6x0tohRv0ZGyZX wJ8zfn1ZIGVlbCIPW9UccMypBTdcQJjbaBiaqULtIw2+6QYKQhJ47+A4Ut97Dl3h7Pzr nYtBnrP8x+VUNaJq8g5LqK3GwV6jmm0hF5NSgmlppQU3XRdDQxalxT+Cibukcytukqv3 7KvrxFzeKmKDZN7rpbIrzy9aFwPV39m4Why+lNfyTEnvS5Vrz3XoqACpgdve5HMoBpiZ /ZiL7p6djCr7dCTKVipjmTDXV34BXgHG2Eh+ALiFsURElZdtCGnoH2CqKMVaoKm1W9/p +FaQ== X-Gm-Message-State: AGRZ1gKhYVf/D7nYAz7VyUvNSyprBJRv3wVK3rZDEFsMA7rHj8ckNQNs YzKYKPQNf5A4/EtdcdrOxnzyWqWC X-Google-Smtp-Source: AJdET5csnpgnlXTXojYEz93SOw5hPVclTJzYRyeUa8iMUmrKgQaNTbC9J1vznGAscOCt7WXSyMc9uQ== X-Received: by 2002:a17:902:8b8a:: with SMTP id ay10-v6mr25221832plb.130.1541490364194; Mon, 05 Nov 2018 23:46:04 -0800 (PST) Received: from jordon-HP-15-Notebook-PC ([103.227.97.85]) by smtp.gmail.com with ESMTPSA id z9-v6sm22039200pfg.174.2018.11.05.23.46.02 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 05 Nov 2018 23:46:02 -0800 (PST) Date: Tue, 6 Nov 2018 13:19:34 +0530 From: Souptick Joarder To: willy@infradead.org, akpm@linux-foundation.org, mhocko@suse.com, kirill.shutemov@linux.intel.com, dan.j.williams@intel.com, vbabka@suse.cz, riel@redhat.com, rppt@linux.ibm.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] mm: Create the new vm_fault_t type Message-ID: <20181106074934.GA27620@jordon-HP-15-Notebook-PC> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Page fault handlers are supposed to return VM_FAULT codes, but some drivers/file systems mistakenly return error numbers. Now that all drivers/file systems have been converted to use the vm_fault_t return type, change the type definition to no longer be compatible with 'int'. By making it an unsigned int, the function prototype becomes incompatible with a function which returns int. Sparse will detect any attempts to return a value which is not a VM_FAULT code. VM_FAULT_SET_HINDEX and VM_FAULT_GET_HINDEX values are changed to avoid conflict with other VM_FAULT codes. Signed-off-by: Souptick Joarder --- v2: Updated the change log and corrected the document part. name added to the enum that kernel-doc able to parse it. include/linux/mm.h | 46 ------------------------------ include/linux/mm_types.h | 73 +++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 72 insertions(+), 47 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index fcf9cc9..511a3ce 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1267,52 +1267,6 @@ static inline void clear_page_pfmemalloc(struct page *page) } /* - * Different kinds of faults, as returned by handle_mm_fault(). - * Used to decide whether a process gets delivered SIGBUS or - * just gets major/minor fault counters bumped up. - */ - -#define VM_FAULT_OOM 0x0001 -#define VM_FAULT_SIGBUS 0x0002 -#define VM_FAULT_MAJOR 0x0004 -#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */ -#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned small page */ -#define VM_FAULT_HWPOISON_LARGE 0x0020 /* Hit poisoned large page. Index encoded in upper bits */ -#define VM_FAULT_SIGSEGV 0x0040 - -#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */ -#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */ -#define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */ -#define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back to small */ -#define VM_FAULT_DONE_COW 0x1000 /* ->fault has fully handled COW */ -#define VM_FAULT_NEEDDSYNC 0x2000 /* ->fault did not modify page tables - * and needs fsync() to complete (for - * synchronous page faults in DAX) */ - -#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \ - VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \ - VM_FAULT_FALLBACK) - -#define VM_FAULT_RESULT_TRACE \ - { VM_FAULT_OOM, "OOM" }, \ - { VM_FAULT_SIGBUS, "SIGBUS" }, \ - { VM_FAULT_MAJOR, "MAJOR" }, \ - { VM_FAULT_WRITE, "WRITE" }, \ - { VM_FAULT_HWPOISON, "HWPOISON" }, \ - { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ - { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ - { VM_FAULT_NOPAGE, "NOPAGE" }, \ - { VM_FAULT_LOCKED, "LOCKED" }, \ - { VM_FAULT_RETRY, "RETRY" }, \ - { VM_FAULT_FALLBACK, "FALLBACK" }, \ - { VM_FAULT_DONE_COW, "DONE_COW" }, \ - { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } - -/* Encode hstate index for a hwpoisoned large page */ -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) - -/* * Can be called by the pagefault handler when it gets a VM_FAULT_OOM. */ extern void pagefault_out_of_memory(void); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5ed8f62..beee607 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -22,7 +22,6 @@ #endif #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) -typedef int vm_fault_t; struct address_space; struct mem_cgroup; @@ -609,6 +608,78 @@ static inline bool mm_tlb_flush_nested(struct mm_struct *mm) struct vm_fault; +/** + * typedef vm_fault_t - Return type for page fault handlers. + * + * Page fault handlers return a bitmask of %VM_FAULT values. + */ +typedef __bitwise unsigned int vm_fault_t; + +/** + * enum - VM_FAULT code + * + * Page fault handlers return a bitmask of these values to tell + * the core VM what happened when handling the fault. Used to decide + * whether a process gets delivered SIGBUS or just gets major/minor + * fault counters bumped up. + * + * @VM_FAULT_OOM: Out Of Memory + * @VM_FAULT_SIGBUS: Bad access + * @VM_FAULT_MAJOR: Page read from storage + * @VM_FAULT_WRITE: Special case for get_user_pages + * @VM_FAULT_HWPOISON: Hit poisoned small page + * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded + * in upper bits + * @VM_FAULT_SIGSEGV: segmentation fault + * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page + * @VM_FAULT_LOCKED: ->fault locked the returned page + * @VM_FAULT_RETRY: ->fault blocked, must retry + * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small + * @VM_FAULT_DONE_COW: ->fault has fully handled COW + * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs + * fsync() to complete (for synchronous page faults + * in DAX) + */ +enum vm_fault_reason { + VM_FAULT_OOM = (__force vm_fault_t)0x000001, + VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, + VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, + VM_FAULT_WRITE = (__force vm_fault_t)0x000008, + VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, + VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, + VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, + VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, + VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, + VM_FAULT_RETRY = (__force vm_fault_t)0x000400, + VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, + VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, + VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, + VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, +}; + +/* Encode hstate index for a hwpoisoned large page */ +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) + +#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ + VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ + VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) + +#define VM_FAULT_RESULT_TRACE \ + { VM_FAULT_OOM, "OOM" }, \ + { VM_FAULT_SIGBUS, "SIGBUS" }, \ + { VM_FAULT_MAJOR, "MAJOR" }, \ + { VM_FAULT_WRITE, "WRITE" }, \ + { VM_FAULT_HWPOISON, "HWPOISON" }, \ + { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ + { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ + { VM_FAULT_NOPAGE, "NOPAGE" }, \ + { VM_FAULT_LOCKED, "LOCKED" }, \ + { VM_FAULT_RETRY, "RETRY" }, \ + { VM_FAULT_FALLBACK, "FALLBACK" }, \ + { VM_FAULT_DONE_COW, "DONE_COW" }, \ + { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } + struct vm_special_mapping { const char *name; /* The name, e.g. "[vdso]". */ -- 1.9.1