Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933382AbbLRESm (ORCPT ); Thu, 17 Dec 2015 23:18:42 -0500 Received: from mail1.asahi-net.or.jp ([202.224.39.197]:23872 "EHLO mail1.asahi-net.or.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753121AbbLRESl (ORCPT ); Thu, 17 Dec 2015 23:18:41 -0500 Date: Fri, 18 Dec 2015 13:18:36 +0900 Message-ID: <87r3ikjso3.wl-ysato@users.sourceforge.jp> From: Yoshinori Sato To: Russell King - ARM Linux Cc: Dan Williams , tomeu.vizoso@collabora.com, m.szyprowski@samsung.com, "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-nvdimm@lists.01.org" , Stephen Rothwell Subject: Re: -next regression: "driver cohandle -EPROBE_DEFER from bus_type.match()" In-Reply-To: <20151217184641.GI8644@n2100.arm.linux.org.uk> References: <20151217184641.GI8644@n2100.arm.linux.org.uk> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM/1.14.9 (=?ISO-8859-4?Q?Goj=F2?=) APEL/10.8 EasyPG/1.0.0 Emacs/24.5 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4241 Lines: 140 On Fri, 18 Dec 2015 03:46:41 +0900, Russell King - ARM Linux wrote: > > On Thu, Dec 17, 2015 at 07:51:14AM -0800, Dan Williams wrote: > > The commit below causes the libnvdimm sub-system to stop loading. > > This is due to the fact that nvdimm_bus_match() returns the result of > > test_bit() which may be negative. If there are any other bus match > > functions using test_bit they may be similarly impacted. > > > > Can we queue a fixup like the following to libnvdimm, and maybe > > others, ahead of this driver core change? > > This is rather annoying. Have we uncovered a latent bug in other > architectures? Well, looking through the test_bit() implementations, > it looks like it. > > I'll drop the patch set for the time being, we can't go around breaking > stuff like this. However, I think the test_bit() result should be > regularised across different architectures - it _looks_ to me like most > implementations return 0/1 values, but there may be some that don't > (maybe the assembly versions?) > > Here's the list I've pulled out so far from the "easy" cases, which all > look like they're returning 0/1 values. > > asm-generic: 0/1 > > /** > * test_bit - Determine whether a bit is set > * @nr: bit number to test > * @addr: Address to start counting from > */ > static inline int test_bit(int nr, const volatile unsigned long *addr) > { > return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); > } > > alpha: 0/1 > > static inline int > test_bit(int nr, const volatile void * addr) > { > return (1UL & (((const int *) addr)[nr >> 5] >> (nr & 31))) != 0UL; > } > > arm: 0/1 > > test_bit(unsigned int nr, const volatile unsigned long *addr) > { > unsigned long mask; > > addr += nr >> 5; > > mask = 1UL << (nr & 0x1f); > > return ((mask & *addr) != 0); > } > > blackfin: 0/1 > > static inline int test_bit(int nr, const volatile unsigned long *addr) > { > volatile const unsigned long *a = addr + (nr >> 5); > return __raw_bit_test_asm(a, nr & 0x1f) != 0; > } > > frv: 0/1 > > static inline int > __constant_test_bit(unsigned long nr, const volatile void *addr) > { > return ((1UL << (nr & 31)) & (((const volatile unsigned int *) addr)[nr >> 5])) != 0; > } > (and similar for __test_bit) > > h8300 uses assembly... no idea 0/1 I think same return of other architecture. > hexagon uses assembly as well... no idea > > ia64: 0/1 > > static __inline__ int > test_bit (int nr, const volatile void *addr) > { > return 1 & (((const volatile __u32 *) addr)[nr >> 5] >> (nr & 31)); > } > > m68k: 0/1 > > static inline int test_bit(int nr, const unsigned long *vaddr) > { > return (vaddr[nr >> 5] & (1UL << (nr & 31))) != 0; > } > > mn10300: 0/1 > > static inline int test_bit(unsigned long nr, const volatile void *addr) > { > return 1UL & (((const volatile unsigned int *) addr)[nr >> 5] >> (nr & 31)); > } > > s390: 0/1 > > static inline int test_bit(unsigned long nr, const volatile unsigned long *ptr) > { > const volatile unsigned char *addr; > > addr = ((const volatile unsigned char *)ptr); > addr += (nr ^ (BITS_PER_LONG - 8)) >> 3; > return (*addr >> (nr & 7)) & 1; > } > > x86: 0/1 for constant, ? for variable > > static __always_inline int constant_test_bit(long nr, const volatile unsigned long *addr) > { > return ((1UL << (nr & (BITS_PER_LONG-1))) & > (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; > } > (presumably variable_test_bit is the same, but I don't know) > > -- > FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up > according to speedtest.net. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Yoshinori Sato -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/