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[92.234.204.186]) by smtp.gmail.com with ESMTPSA id qa7sm17277959wjc.39.2016.10.12.17.20.26 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 12 Oct 2016 17:20:26 -0700 (PDT) From: Lorenzo Stoakes To: linux-mm@kvack.org Subject: [PATCH 01/10] mm: remove write/force parameters from __get_user_pages_locked() Date: Thu, 13 Oct 2016 01:20:11 +0100 Message-Id: <20161013002020.3062-2-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> X-Mailman-Approved-At: Thu, 13 Oct 2016 01:01:21 +0000 Cc: linux-mips@linux-mips.org, linux-fbdev@vger.kernel.org, Jan Kara , kvm@vger.kernel.org, linux-sh@vger.kernel.org, Dave Hansen , dri-devel@lists.freedesktop.org, netdev@vger.kernel.org, sparclinux@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Hugh Dickins , linux-media@vger.kernel.org, Rik van Riel , intel-gfx@lists.freedesktop.org, adi-buildroot-devel@lists.sourceforge.net, ceph-devel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Lorenzo Stoakes , linux-cris-kernel@axis.com, Linus Torvalds , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-alpha@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Mel Gorman X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP This patch removes the write and force parameters from __get_user_pages_locked() to make the use of FOLL_FORCE explicit in callers as use of this flag can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes Reviewed-by: Jan Kara --- mm/gup.c | 47 +++++++++++++++++++++++++++++++++-------------- 1 file changed, 33 insertions(+), 14 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 96b2b2f..ba83942 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -729,7 +729,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, struct vm_area_struct **vmas, int *locked, bool notify_drop, @@ -747,10 +746,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, if (pages) flags |= FOLL_GET; - if (write) - flags |= FOLL_WRITE; - if (force) - flags |= FOLL_FORCE; pages_done = 0; lock_dropped = false; @@ -846,9 +841,15 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages, int *locked) { + unsigned int flags = FOLL_TOUCH; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + return __get_user_pages_locked(current, current->mm, start, nr_pages, - write, force, pages, NULL, locked, true, - FOLL_TOUCH); + pages, NULL, locked, true, flags); } EXPORT_SYMBOL(get_user_pages_locked); @@ -869,9 +870,15 @@ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct m { long ret; int locked = 1; + + if (write) + gup_flags |= FOLL_WRITE; + if (force) + gup_flags |= FOLL_FORCE; + down_read(&mm->mmap_sem); - ret = __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, NULL, &locked, false, gup_flags); + ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, NULL, + &locked, false, gup_flags); if (locked) up_read(&mm->mmap_sem); return ret; @@ -963,9 +970,15 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, int write, int force, struct page **pages, struct vm_area_struct **vmas) { - return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, vmas, NULL, false, - FOLL_TOUCH | FOLL_REMOTE); + unsigned int flags = FOLL_TOUCH | FOLL_REMOTE; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + + return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, + NULL, false, flags); } EXPORT_SYMBOL(get_user_pages_remote); @@ -979,9 +992,15 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages, struct vm_area_struct **vmas) { + unsigned int flags = FOLL_TOUCH; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + return __get_user_pages_locked(current, current->mm, start, nr_pages, - write, force, pages, vmas, NULL, false, - FOLL_TOUCH); + pages, vmas, NULL, false, flags); } EXPORT_SYMBOL(get_user_pages);