From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 07/25] lib: fix bitmap_parse() on 64-bit big endian archs Date: Wed, 10 Jun 2020 18:41:41 -0700 Message-ID: <20200611014141.jChxhHGSk%akpm@linux-foundation.org> References: <20200610184053.3fa7368ab80e23bfd44de71f@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:50400 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726163AbgFKBln (ORCPT ); Wed, 10 Jun 2020 21:41:43 -0400 In-Reply-To: <20200610184053.3fa7368ab80e23bfd44de71f@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: acme@redhat.com, agordeev@linux.ibm.com, akpm@linux-foundation.org, amritha.nambiar@intel.com, andriy.shevchenko@linux.intel.com, andy.shevchenko@gmail.com, chris@chris-wilson.co.uk, keescook@chromium.org, linux-mm@kvack.org, linux@rasmusvillemoes.dk, mm-commits@vger.kernel.org, mszeredi@redhat.com, stable@vger.kernel.org, steffen.klassert@secunet.com, tobin@kernel.org, torvalds@linux-foundation.org, vineet.gupta1@synopsys.com, will.deacon@arm.com, willemb@google.com, willy@infradead.org, yury.norov@gmail.com From: Alexander Gordeev Subject: lib: fix bitmap_parse() on 64-bit big endian archs Commit 2d6261583be0 ("lib: rework bitmap_parse()") does not take into account order of halfwords on 64-bit big endian architectures. As result (at least) Receive Packet Steering, IRQ affinity masks and runtime kernel test "test_bitmap" get broken on s390. [andriy.shevchenko@linux.intel.com: convert infinite while loop to a for loop] Link: http://lkml.kernel.org/r/20200609140535.87160-1-andriy.shevchenko@linux.intel.com Link: http://lkml.kernel.org/r/1591634471-17647-1-git-send-email-agordeev@linux.ibm.com Fixes: 2d6261583be0 ("lib: rework bitmap_parse()") Signed-off-by: Alexander Gordeev Signed-off-by: Andy Shevchenko Reviewed-by: Andy Shevchenko Cc: Yury Norov Cc: Amritha Nambiar Cc: Arnaldo Carvalho de Melo Cc: Chris Wilson Cc: Kees Cook Cc: Matthew Wilcox Cc: Miklos Szeredi Cc: Rasmus Villemoes Cc: Steffen Klassert Cc: "Tobin C . Harding" Cc: Vineet Gupta Cc: Will Deacon Cc: Willem de Bruijn Cc: Signed-off-by: Andrew Morton --- lib/bitmap.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/lib/bitmap.c~lib-fix-bitmap_parse-on-64-bit-big-endian-archs +++ a/lib/bitmap.c @@ -741,8 +741,9 @@ int bitmap_parse(const char *start, unsi int chunks = BITS_TO_U32(nmaskbits); u32 *bitmap = (u32 *)maskp; int unset_bit; + int chunk; - while (1) { + for (chunk = 0; ; chunk++) { end = bitmap_find_region_reverse(start, end); if (start > end) break; @@ -750,7 +751,11 @@ int bitmap_parse(const char *start, unsi if (!chunks--) return -EOVERFLOW; - end = bitmap_get_x32_reverse(start, end, bitmap++); +#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN) + end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]); +#else + end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]); +#endif if (IS_ERR(end)) return PTR_ERR(end); } _