From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Stoakes Subject: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Date: Thu, 13 Oct 2016 01:20:18 +0100 Message-ID: <20161013002020.3062-9-lstoakes@gmail.com> References: <20161013002020.3062-1-lstoakes@gmail.com> Return-path: In-Reply-To: <20161013002020.3062-1-lstoakes@gmail.com> Sender: owner-linux-mm@kvack.org To: linux-mm@kvack.org Cc: Linus Torvalds , Jan Kara , Hugh Dickins , Dave Hansen , Rik van Riel , Mel Gorman , Andrew Morton , adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cris-kernel@axis.com, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@linux-mips.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kerne List-Id: ceph-devel.vger.kernel.org This patch removes the write parameter from __access_remote_vm() and replaces it with a gup_flags parameter as use of this function previously _implied_ FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes --- mm/memory.c | 23 +++++++++++++++-------- mm/nommu.c | 9 ++++++--- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 20a9adb..79ebed3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3869,14 +3869,11 @@ EXPORT_SYMBOL_GPL(generic_access_phys); * given task for page fault accounting. */ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; void *old_buf = buf; - unsigned int flags = FOLL_FORCE; - - if (write) - flags |= FOLL_WRITE; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); /* ignore errors, just check how much was successfully transferred */ @@ -3886,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, struct page *page = NULL; ret = get_user_pages_remote(tsk, mm, addr, 1, - flags, &page, &vma); + gup_flags, &page, &vma); if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; @@ -3945,7 +3942,12 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + unsigned int flags = FOLL_FORCE; + + if (write) + flags |= FOLL_WRITE; + + return __access_remote_vm(NULL, mm, addr, buf, len, flags); } /* @@ -3958,12 +3960,17 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, { struct mm_struct *mm; int ret; + unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - ret = __access_remote_vm(tsk, mm, addr, buf, len, write); + if (write) + flags |= FOLL_WRITE; + + ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + mmput(mm); return ret; diff --git a/mm/nommu.c b/mm/nommu.c index 70cb844..bde7df3 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1809,9 +1809,10 @@ void filemap_map_pages(struct fault_env *fe, EXPORT_SYMBOL(filemap_map_pages); static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); @@ -1853,7 +1854,8 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + return __access_remote_vm(NULL, mm, addr, buf, len, + write ? FOLL_WRITE : 0); } /* @@ -1871,7 +1873,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (!mm) return 0; - len = __access_remote_vm(tsk, mm, addr, buf, len, write); + len = __access_remote_vm(tsk, mm, addr, buf, len, + write ? FOLL_WRITE : 0); mmput(mm); return len; -- 2.10.0 -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Stoakes Date: Thu, 13 Oct 2016 00:20:18 +0000 Subject: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Message-Id: <20161013002020.3062-9-lstoakes@gmail.com> List-Id: References: <20161013002020.3062-1-lstoakes@gmail.com> In-Reply-To: <20161013002020.3062-1-lstoakes@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-mm@kvack.org Cc: Linus Torvalds , Jan Kara , Hugh Dickins , Dave Hansen , Rik van Riel , Mel Gorman , Andrew Morton , adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cris-kernel@axis.com, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@linux-mips.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kerne This patch removes the write parameter from __access_remote_vm() and replaces it with a gup_flags parameter as use of this function previously _implied_ FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes --- mm/memory.c | 23 +++++++++++++++-------- mm/nommu.c | 9 ++++++--- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 20a9adb..79ebed3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3869,14 +3869,11 @@ EXPORT_SYMBOL_GPL(generic_access_phys); * given task for page fault accounting. */ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; void *old_buf = buf; - unsigned int flags = FOLL_FORCE; - - if (write) - flags |= FOLL_WRITE; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); /* ignore errors, just check how much was successfully transferred */ @@ -3886,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, struct page *page = NULL; ret = get_user_pages_remote(tsk, mm, addr, 1, - flags, &page, &vma); + gup_flags, &page, &vma); if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; @@ -3945,7 +3942,12 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + unsigned int flags = FOLL_FORCE; + + if (write) + flags |= FOLL_WRITE; + + return __access_remote_vm(NULL, mm, addr, buf, len, flags); } /* @@ -3958,12 +3960,17 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, { struct mm_struct *mm; int ret; + unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - ret = __access_remote_vm(tsk, mm, addr, buf, len, write); + if (write) + flags |= FOLL_WRITE; + + ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + mmput(mm); return ret; diff --git a/mm/nommu.c b/mm/nommu.c index 70cb844..bde7df3 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1809,9 +1809,10 @@ void filemap_map_pages(struct fault_env *fe, EXPORT_SYMBOL(filemap_map_pages); static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); @@ -1853,7 +1854,8 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + return __access_remote_vm(NULL, mm, addr, buf, len, + write ? FOLL_WRITE : 0); } /* @@ -1871,7 +1873,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (!mm) return 0; - len = __access_remote_vm(tsk, mm, addr, buf, len, write); + len = __access_remote_vm(tsk, mm, addr, buf, len, + write ? FOLL_WRITE : 0); mmput(mm); return len; -- 2.10.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 13 Oct 2016 02:23:52 +0200 (CEST) Received: from mail-lf0-f65.google.com ([209.85.215.65]:33910 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23993004AbcJMAUrukdX4 (ORCPT ); Thu, 13 Oct 2016 02:20:47 +0200 Received: by mail-lf0-f65.google.com with SMTP id x23so3968583lfi.1 for ; Wed, 12 Oct 2016 17:20:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=YtCTnPnKl7iOzKo94LN8YtKRwhKeaOyj++/afSUhTg8=; b=T8lGnI3g8EgzPX2ur/FmxLhX1Qvi3z2z14HovnNxNT9T+DGUy5gnRVABy/tTPZEVvl EPWDDhpc+byHt3iebnB2GFt7XZLRBjUOgtPQv3EYC8Bfs2sUxGz5zGpd3znmoG5VqTE6 TQBXyofuyuKOgD800XXdIUh0HCjQkWgvGxj7ioFI3i/L+sPN9RDdQhlUizfivrDQBmVJ q+rLPIbHiUlJ2RTIS6QfINu+iXFjzirMlJnbFyvTNtBTXUTvY8f2lor/ezyHKvgwVbSm MW9sFjSoZiKtiFp5HuoT0YL2qW/HlfMTH52tMfkF4apqGUcq7Ryf4RFvqiWkzH44RapR oX6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=YtCTnPnKl7iOzKo94LN8YtKRwhKeaOyj++/afSUhTg8=; b=d6Zms7Vw7UEbMsm5PuYCUEkQwaJd6XH9QY4dwnlvzWSFpOxBqoF+t/biIRbW1tUr+/ nyEuiISUsusyKcyZOillmJfEmUItXDBwnMQvvTYtYNBj2c6oe5nxWhOswOx9axGOszUY lP4nsYW7k5usWzSTOLlzWZ6nUhE7fO415cNIQww4wo2QlnHCowJtstVkq3QvEVlGlFIr ocrkMtOUw7qlU1/B299hcfapAtyLJSEsB1V9HxMElGxUA1slSPU3kaVmyCPkVyOAYO7w xKR8QQukakYqQ1lkIDUevj6Fc1eoa6RJ8C49J2csRTj4f5wo55s00sDF1NlPaqkYr79+ 7C6g== X-Gm-Message-State: AA6/9RlAQL59FPplS0FzkvkD3uGLEQcBAzCwMQv+4vFUlFgpKkTobM6waECPhhCZBO7DKQ== X-Received: by 10.28.175.77 with SMTP id y74mr17295wme.114.1476318042381; Wed, 12 Oct 2016 17:20:42 -0700 (PDT) Received: from localhost (cpc94060-newt37-2-0-cust185.19-3.cable.virginm.net. [92.234.204.186]) by smtp.gmail.com with ESMTPSA id v3sm17413357wjm.4.2016.10.12.17.20.40 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 12 Oct 2016 17:20:40 -0700 (PDT) From: Lorenzo Stoakes To: linux-mm@kvack.org Cc: Linus Torvalds , Jan Kara , Hugh Dickins , Dave Hansen , Rik van Riel , Mel Gorman , Andrew Morton , adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cris-kernel@axis.com, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@linux-mips.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, Lorenzo Stoakes Subject: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Date: Thu, 13 Oct 2016 01:20:18 +0100 Message-Id: <20161013002020.3062-9-lstoakes@gmail.com> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161013002020.3062-1-lstoakes@gmail.com> References: <20161013002020.3062-1-lstoakes@gmail.com> Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 55410 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: lstoakes@gmail.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips This patch removes the write parameter from __access_remote_vm() and replaces it with a gup_flags parameter as use of this function previously _implied_ FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes --- mm/memory.c | 23 +++++++++++++++-------- mm/nommu.c | 9 ++++++--- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 20a9adb..79ebed3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3869,14 +3869,11 @@ EXPORT_SYMBOL_GPL(generic_access_phys); * given task for page fault accounting. */ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; void *old_buf = buf; - unsigned int flags = FOLL_FORCE; - - if (write) - flags |= FOLL_WRITE; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); /* ignore errors, just check how much was successfully transferred */ @@ -3886,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, struct page *page = NULL; ret = get_user_pages_remote(tsk, mm, addr, 1, - flags, &page, &vma); + gup_flags, &page, &vma); if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; @@ -3945,7 +3942,12 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + unsigned int flags = FOLL_FORCE; + + if (write) + flags |= FOLL_WRITE; + + return __access_remote_vm(NULL, mm, addr, buf, len, flags); } /* @@ -3958,12 +3960,17 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, { struct mm_struct *mm; int ret; + unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - ret = __access_remote_vm(tsk, mm, addr, buf, len, write); + if (write) + flags |= FOLL_WRITE; + + ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + mmput(mm); return ret; diff --git a/mm/nommu.c b/mm/nommu.c index 70cb844..bde7df3 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1809,9 +1809,10 @@ void filemap_map_pages(struct fault_env *fe, EXPORT_SYMBOL(filemap_map_pages); static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); @@ -1853,7 +1854,8 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + return __access_remote_vm(NULL, mm, addr, buf, len, + write ? FOLL_WRITE : 0); } /* @@ -1871,7 +1873,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (!mm) return 0; - len = __access_remote_vm(tsk, mm, addr, buf, len, write); + len = __access_remote_vm(tsk, mm, addr, buf, len, + write ? FOLL_WRITE : 0); mmput(mm); return len; -- 2.10.0 From mboxrd@z Thu Jan 1 00:00:00 1970 From: lstoakes@gmail.com (Lorenzo Stoakes) Date: Thu, 13 Oct 2016 01:20:18 +0100 Subject: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags In-Reply-To: <20161013002020.3062-1-lstoakes@gmail.com> References: <20161013002020.3062-1-lstoakes@gmail.com> Message-ID: <20161013002020.3062-9-lstoakes@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This patch removes the write parameter from __access_remote_vm() and replaces it with a gup_flags parameter as use of this function previously _implied_ FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes --- mm/memory.c | 23 +++++++++++++++-------- mm/nommu.c | 9 ++++++--- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 20a9adb..79ebed3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3869,14 +3869,11 @@ EXPORT_SYMBOL_GPL(generic_access_phys); * given task for page fault accounting. */ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; void *old_buf = buf; - unsigned int flags = FOLL_FORCE; - - if (write) - flags |= FOLL_WRITE; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); /* ignore errors, just check how much was successfully transferred */ @@ -3886,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, struct page *page = NULL; ret = get_user_pages_remote(tsk, mm, addr, 1, - flags, &page, &vma); + gup_flags, &page, &vma); if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; @@ -3945,7 +3942,12 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + unsigned int flags = FOLL_FORCE; + + if (write) + flags |= FOLL_WRITE; + + return __access_remote_vm(NULL, mm, addr, buf, len, flags); } /* @@ -3958,12 +3960,17 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, { struct mm_struct *mm; int ret; + unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - ret = __access_remote_vm(tsk, mm, addr, buf, len, write); + if (write) + flags |= FOLL_WRITE; + + ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + mmput(mm); return ret; diff --git a/mm/nommu.c b/mm/nommu.c index 70cb844..bde7df3 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1809,9 +1809,10 @@ void filemap_map_pages(struct fault_env *fe, EXPORT_SYMBOL(filemap_map_pages); static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); @@ -1853,7 +1854,8 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + return __access_remote_vm(NULL, mm, addr, buf, len, + write ? FOLL_WRITE : 0); } /* @@ -1871,7 +1873,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (!mm) return 0; - len = __access_remote_vm(tsk, mm, addr, buf, len, write); + len = __access_remote_vm(tsk, mm, addr, buf, len, + write ? FOLL_WRITE : 0); mmput(mm); return len; -- 2.10.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Lorenzo Stoakes To: linux-mm@kvack.org Cc: Linus Torvalds , Jan Kara , Hugh Dickins , Dave Hansen , Rik van Riel , Mel Gorman , Andrew Morton , adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kvm@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cris-kernel@axis.com, linux-fbdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@linux-mips.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, Lorenzo Stoakes Subject: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Date: Thu, 13 Oct 2016 01:20:18 +0100 Message-Id: <20161013002020.3062-9-lstoakes@gmail.com> In-Reply-To: <20161013002020.3062-1-lstoakes@gmail.com> References: <20161013002020.3062-1-lstoakes@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: This patch removes the write parameter from __access_remote_vm() and replaces it with a gup_flags parameter as use of this function previously _implied_ FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes --- mm/memory.c | 23 +++++++++++++++-------- mm/nommu.c | 9 ++++++--- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 20a9adb..79ebed3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3869,14 +3869,11 @@ EXPORT_SYMBOL_GPL(generic_access_phys); * given task for page fault accounting. */ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; void *old_buf = buf; - unsigned int flags = FOLL_FORCE; - - if (write) - flags |= FOLL_WRITE; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); /* ignore errors, just check how much was successfully transferred */ @@ -3886,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, struct page *page = NULL; ret = get_user_pages_remote(tsk, mm, addr, 1, - flags, &page, &vma); + gup_flags, &page, &vma); if (ret <= 0) { #ifndef CONFIG_HAVE_IOREMAP_PROT break; @@ -3945,7 +3942,12 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + unsigned int flags = FOLL_FORCE; + + if (write) + flags |= FOLL_WRITE; + + return __access_remote_vm(NULL, mm, addr, buf, len, flags); } /* @@ -3958,12 +3960,17 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, { struct mm_struct *mm; int ret; + unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - ret = __access_remote_vm(tsk, mm, addr, buf, len, write); + if (write) + flags |= FOLL_WRITE; + + ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + mmput(mm); return ret; diff --git a/mm/nommu.c b/mm/nommu.c index 70cb844..bde7df3 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1809,9 +1809,10 @@ void filemap_map_pages(struct fault_env *fe, EXPORT_SYMBOL(filemap_map_pages); static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, - unsigned long addr, void *buf, int len, int write) + unsigned long addr, void *buf, int len, unsigned int gup_flags) { struct vm_area_struct *vma; + int write = gup_flags & FOLL_WRITE; down_read(&mm->mmap_sem); @@ -1853,7 +1854,8 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, int write) { - return __access_remote_vm(NULL, mm, addr, buf, len, write); + return __access_remote_vm(NULL, mm, addr, buf, len, + write ? FOLL_WRITE : 0); } /* @@ -1871,7 +1873,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in if (!mm) return 0; - len = __access_remote_vm(tsk, mm, addr, buf, len, write); + len = __access_remote_vm(tsk, mm, addr, buf, len, + write ? FOLL_WRITE : 0); mmput(mm); return len; -- 2.10.0 -- 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