From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id 4B9066B00CB for ; Wed, 22 May 2013 10:30:52 -0400 (EDT) Date: Wed, 22 May 2013 17:30:00 +0300 From: "Michael S. Tsirkin" Subject: Re: [PATCH v2 07/10] powerpc: uaccess s/might_sleep/might_fault/ Message-ID: <20130522143000.GA21886@redhat.com> References: <2aa6c3da21a28120126732b5e0b4ecd6cba8ca3b.1368702323.git.mst@redhat.com> <201305221559.01806.arnd@arndb.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201305221559.01806.arnd@arndb.de> Sender: owner-linux-mm@kvack.org List-ID: To: Arnd Bergmann Cc: linux-kernel@vger.kernel.org, Catalin Marinas , Will Deacon , David Howells , Hirokazu Takata , Michal Simek , Koichi Yasutake , Benjamin Herrenschmidt , Paul Mackerras , Chris Metcalf , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , "H. Peter Anvin" , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-m32r@ml.linux-m32r.org, linux-m32r-ja@ml.linux-m32r.org, microblaze-uclinux@itee.uq.edu.au, linux-am33-list@redhat.com, linuxppc-dev@lists.ozlabs.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org On Wed, May 22, 2013 at 03:59:01PM +0200, Arnd Bergmann wrote: > On Thursday 16 May 2013, Michael S. Tsirkin wrote: > > @@ -178,7 +178,7 @@ do { \ > > long __pu_err; \ > > __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ > > if (!is_kernel_addr((unsigned long)__pu_addr)) \ > > - might_sleep(); \ > > + might_fault(); \ > > __chk_user_ptr(ptr); \ > > __put_user_size((x), __pu_addr, (size), __pu_err); \ > > __pu_err; \ > > > > Another observation: > > if (!is_kernel_addr((unsigned long)__pu_addr)) > might_sleep(); > > is almost the same as > > might_fault(); > > except that it does not call might_lock_read(). > > The version above may have been put there intentionally and correctly, but > if you want to replace it with might_fault(), you should remove the > "if ()" condition. > > Arnd Good point, thanks. I think I'll do it in a separate patch on top, just to make sure bisect does not result in a revision that produces false positive warnings. -- MST -- 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