From patchwork Wed Mar 6 08:07:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herve Codina X-Patchwork-Id: 13583468 Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE1EC5CDD2; Wed, 6 Mar 2024 08:07:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.200 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709712479; cv=none; b=Wql7b4b1qjL2iJVNX56HVWmqqR9NdHa1KwIyilLV/TFv9cCOYm/CBPCwyVoaxFiAXP1l1EzqFqxhkLl8s+1iSBgvSGvyBm24Fip9+RaK3ZUahb/bn24qp8Lz/B0hjaQ8VncpQWR+BVk7NETW5QdBRWBce31H6qsrY8ED4ShBgp8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709712479; c=relaxed/simple; bh=OnX+53TXkbqIWk5yp7KeROTCIa9DDDGyw6vZPgwK6Co=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bzqWToKGh7hZv8sR8RkjmaRsJ6zYPvUNT95U7jamNSL1aLRDQAcJdvfOA+tn8rvSdrZqZ3SBkDDSuozfqcOGFZ+HLflO+7WBcdnt+XCp2bEiN4qIvfBG5Vum6Kppl9s+sJg/iUOBuoVqBqEYGlgdPC8cDydO8ZaA1l8nWUP1PjQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=JtjBCJZc; arc=none smtp.client-ip=217.70.183.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="JtjBCJZc" Received: by mail.gandi.net (Postfix) with ESMTPA id 887BF20002; Wed, 6 Mar 2024 08:07:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1709712469; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s52XVNKgkl9FtWVL4lxN6JUvQsPW5Z/X/q3oXZCSzZU=; b=JtjBCJZcIenSycZ2xsOS+pcqFtzQUMHZW6Zrb7qY08cFa9beWLaUTLnSk1DOnqBxg08F0K 8WFHtjYb8AF1hyaeE3Y4PP5+WldH1h5ExetBfkXA4R4CZioaD7dzDAITsRtB+CZyAn2PZV 5iMU04jZOqdciXTAZuKFiJHb3dUZ5DyoUnYUL//0XpaFLC3MG4t5mqxLziL+dJi9A4eLaa UaObKQLPkNq4mkFLlfw58NVgymkQxd2giGa3GJo2JRUJzdPVMKEZkZ7MLjYF/tYeCYCiMa lOoqH3fLFQ0ZPN2ePkbS5238Elnqhj0DuCkAS+o4HbKvVnTApEvbsTqEWhYfrQ== From: Herve Codina To: Vadim Fedorenko , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Herve Codina , Yury Norov , Andy Shevchenko , Rasmus Villemoes Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Andrew Lunn , Mark Brown , Christophe Leroy , Thomas Petazzoni Subject: [PATCH v6 3/5] lib/bitmap: Introduce bitmap_scatter() and bitmap_gather() helpers Date: Wed, 6 Mar 2024 09:07:19 +0100 Message-ID: <20240306080726.167338-4-herve.codina@bootlin.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240306080726.167338-1-herve.codina@bootlin.com> References: <20240306080726.167338-1-herve.codina@bootlin.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-GND-Sasl: herve.codina@bootlin.com From: Andy Shevchenko These helpers scatters or gathers a bitmap with the help of the mask position bits parameter. bitmap_scatter() does the following: src: 0000000001011010 |||||| +------+||||| | +----+|||| | |+----+||| | || +-+|| | || | || mask: ...v..vv...v..vv ...0..11...0..10 dst: 0000001100000010 and bitmap_gather() performs this one: mask: ...v..vv...v..vv src: 0000001100000010 ^ ^^ ^ 0 | || | 10 | || > 010 | |+--> 1010 | +--> 11010 +----> 011010 dst: 0000000000011010 bitmap_gather() can the seen as the reverse bitmap_scatter() operation. Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/lkml/20230926052007.3917389-3-andriy.shevchenko@linux.intel.com/ Co-developed-by: Herve Codina Signed-off-by: Herve Codina Signed-off-by: Yury Norov --- include/linux/bitmap.h | 101 +++++++++++++++++++++++++++++++++++++++++ lib/test_bitmap.c | 42 +++++++++++++++++ 2 files changed, 143 insertions(+) diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 99451431e4d6..049ba20911c5 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -62,6 +62,8 @@ struct device; * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n * bitmap_cut(dst, src, first, n, nbits) Cut n bits from first, copy rest * bitmap_replace(dst, old, new, mask, nbits) *dst = (*old & ~(*mask)) | (*new & *mask) + * bitmap_scatter(dst, src, mask, nbits) *dst = map(dense, sparse)(src) + * bitmap_gather(dst, src, mask, nbits) *dst = map(sparse, dense)(src) * bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src) * bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit) * bitmap_onto(dst, orig, relmap, nbits) *dst = orig relative to relmap @@ -487,6 +489,105 @@ static inline void bitmap_replace(unsigned long *dst, __bitmap_replace(dst, old, new, mask, nbits); } +/** + * bitmap_scatter - Scatter a bitmap according to the given mask + * @dst: scattered bitmap + * @src: gathered bitmap + * @mask: mask representing bits to assign to in the scattered bitmap + * @nbits: number of bits in each of these bitmaps + * + * Scatters bitmap with sequential bits according to the given @mask. + * + * Example: + * If @src bitmap = 0x005a, with @mask = 0x1313, @dst will be 0x0302. + * + * Or in binary form + * @src @mask @dst + * 0000000001011010 0001001100010011 0000001100000010 + * + * (Bits 0, 1, 2, 3, 4, 5 are copied to the bits 0, 1, 4, 8, 9, 12) + * + * A more 'visual' description of the operation: + * src: 0000000001011010 + * |||||| + * +------+||||| + * | +----+|||| + * | |+----+||| + * | || +-+|| + * | || | || + * mask: ...v..vv...v..vv + * ...0..11...0..10 + * dst: 0000001100000010 + * + * A relationship exists between bitmap_scatter() and bitmap_gather(). + * bitmap_gather() can be seen as the 'reverse' bitmap_scatter() operation. + * See bitmap_scatter() for details related to this relationship. + */ +static inline void bitmap_scatter(unsigned long *dst, const unsigned long *src, + const unsigned long *mask, unsigned int nbits) +{ + unsigned int n = 0; + unsigned int bit; + + bitmap_zero(dst, nbits); + + for_each_set_bit(bit, mask, nbits) + __assign_bit(bit, dst, test_bit(n++, src)); +} + +/** + * bitmap_gather - Gather a bitmap according to given mask + * @dst: gathered bitmap + * @src: scattered bitmap + * @mask: mask representing bits to extract from in the scattered bitmap + * @nbits: number of bits in each of these bitmaps + * + * Gathers bitmap with sparse bits according to the given @mask. + * + * Example: + * If @src bitmap = 0x0302, with @mask = 0x1313, @dst will be 0x001a. + * + * Or in binary form + * @src @mask @dst + * 0000001100000010 0001001100010011 0000000000011010 + * + * (Bits 0, 1, 4, 8, 9, 12 are copied to the bits 0, 1, 2, 3, 4, 5) + * + * A more 'visual' description of the operation: + * mask: ...v..vv...v..vv + * src: 0000001100000010 + * ^ ^^ ^ 0 + * | || | 10 + * | || > 010 + * | |+--> 1010 + * | +--> 11010 + * +----> 011010 + * dst: 0000000000011010 + * + * A relationship exists between bitmap_gather() and bitmap_scatter(). See + * bitmap_scatter() for the bitmap scatter detailed operations. + * Suppose scattered computed using bitmap_scatter(scattered, src, mask, n). + * The operation bitmap_gather(result, scattered, mask, n) leads to a result + * equal or equivalent to src. + * + * The result can be 'equivalent' because bitmap_scatter() and bitmap_gather() + * are not bijective. + * The result and src values are equivalent in that sense that a call to + * bitmap_scatter(res, src, mask, n) and a call to + * bitmap_scatter(res, result, mask, n) will lead to the same res value. + */ +static inline void bitmap_gather(unsigned long *dst, const unsigned long *src, + const unsigned long *mask, unsigned int nbits) +{ + unsigned int n = 0; + unsigned int bit; + + bitmap_zero(dst, nbits); + + for_each_set_bit(bit, mask, nbits) + __assign_bit(n++, dst, test_bit(bit, src)); +} + static inline void bitmap_next_set_region(unsigned long *bitmap, unsigned int *rs, unsigned int *re, unsigned int end) diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c index 65f22c2578b0..6b2b33579f56 100644 --- a/lib/test_bitmap.c +++ b/lib/test_bitmap.c @@ -380,6 +380,47 @@ static void __init test_replace(void) expect_eq_bitmap(bmap, exp3_1_0, nbits); } +static const unsigned long sg_mask[] __initconst = { + BITMAP_FROM_U64(0x000000000000035aULL), +}; + +static const unsigned long sg_src[] __initconst = { + BITMAP_FROM_U64(0x0000000000000667ULL), +}; + +static const unsigned long sg_gather_exp[] __initconst = { + BITMAP_FROM_U64(0x0000000000000029ULL), +}; + +static const unsigned long sg_scatter_exp[] __initconst = { + BITMAP_FROM_U64(0x000000000000021aULL), +}; + +static void __init test_bitmap_sg(void) +{ + unsigned int nbits = 64; + DECLARE_BITMAP(bmap_gather, 100); + DECLARE_BITMAP(bmap_scatter, 100); + DECLARE_BITMAP(bmap_tmp, 100); + DECLARE_BITMAP(bmap_res, 100); + + /* Simple gather call */ + bitmap_zero(bmap_gather, 100); + bitmap_gather(bmap_gather, sg_src, sg_mask, nbits); + expect_eq_bitmap(sg_gather_exp, bmap_gather, nbits); + + /* Simple scatter call */ + bitmap_zero(bmap_scatter, 100); + bitmap_scatter(bmap_scatter, sg_src, sg_mask, nbits); + expect_eq_bitmap(sg_scatter_exp, bmap_scatter, nbits); + + /* Scatter/gather relationship */ + bitmap_zero(bmap_tmp, 100); + bitmap_gather(bmap_tmp, bmap_scatter, sg_mask, nbits); + bitmap_scatter(bmap_res, bmap_tmp, sg_mask, nbits); + expect_eq_bitmap(bmap_scatter, bmap_res, nbits); +} + #define PARSE_TIME 0x1 #define NO_LEN 0x2 @@ -1252,6 +1293,7 @@ static void __init selftest(void) test_copy(); test_bitmap_region(); test_replace(); + test_bitmap_sg(); test_bitmap_arr32(); test_bitmap_arr64(); test_bitmap_parse();