From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF6E4C4708F for ; Wed, 2 Jun 2021 14:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B0B01610A1 for ; Wed, 2 Jun 2021 14:22:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230072AbhFBOYG (ORCPT ); Wed, 2 Jun 2021 10:24:06 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3132 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229667AbhFBOYE (ORCPT ); Wed, 2 Jun 2021 10:24:04 -0400 Received: from fraeml740-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Fw9wp3Md2z6V0mN; Wed, 2 Jun 2021 22:13:14 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml740-chm.china.huawei.com (10.206.15.221) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 2 Jun 2021 16:22:19 +0200 Received: from localhost (10.52.124.142) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Wed, 2 Jun 2021 15:22:18 +0100 Date: Wed, 2 Jun 2021 15:22:17 +0100 From: Jonathan Cameron To: Tian Tao CC: , , , , , Subject: Re: [PATCH v2 1/3] lib: bitmap: introduce bitmap_print_to_buf Message-ID: <20210602152217.00007f13@Huawei.com> In-Reply-To: <1622641734-22538-2-git-send-email-tiantao6@hisilicon.com> References: <1622641734-22538-1-git-send-email-tiantao6@hisilicon.com> <1622641734-22538-2-git-send-email-tiantao6@hisilicon.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.52.124.142] X-ClientProxiedBy: lhreml709-chm.china.huawei.com (10.201.108.58) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2 Jun 2021 21:48:52 +0800 Tian Tao wrote: > New API bitmap_print_to_buf() with bin_attribute to avoid maskp > exceeding PAGE_SIZE. bitmap_print_to_pagebuf() is a special case > of bitmap_print_to_buf(), so in bitmap_print_to_pagebuf() call > bitmap_print_to_buf(). > > Signed-off-by: Tian Tao Hi, I think you need strlen() + 1 as strlen() doesn't include the null terminator. Also good to add () in a few more places to make the hyperlinks work in the html docs (fairly sure it needs those) I don't really like the fact we can't get the string length without that extra call (as it's buried in the kasprintf() implementation) but this is unlikely to be a high performance path so clean code is better. Otherwise, LGTM > --- > include/linux/bitmap.h | 3 +++ > include/linux/cpumask.h | 21 +++++++++++++++++++++ > lib/bitmap.c | 38 ++++++++++++++++++++++++++++++++++++-- > 3 files changed, 60 insertions(+), 2 deletions(-) > > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h > index 70a9324..bc401bd9b 100644 > --- a/include/linux/bitmap.h > +++ b/include/linux/bitmap.h > @@ -219,6 +219,9 @@ extern unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int > extern int bitmap_print_to_pagebuf(bool list, char *buf, > const unsigned long *maskp, int nmaskbits); > > +extern int bitmap_print_to_buf(bool list, char *buf, > + const unsigned long *maskp, int nmaskbits, loff_t off, size_t count); > + > #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) > #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) > > diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h > index 383684e..56852f2 100644 > --- a/include/linux/cpumask.h > +++ b/include/linux/cpumask.h > @@ -928,6 +928,27 @@ cpumap_print_to_pagebuf(bool list, char *buf, const struct cpumask *mask) > nr_cpu_ids); > } > > +/** > + * cpumap_print_to_buf - copies the cpumask into the buffer either > + * as comma-separated list of cpus or hex values of cpumask > + * @list: indicates whether the cpumap must be list > + * @mask: the cpumask to copy > + * @buf: the buffer to copy into > + * @off: in the string from which we are copying, We copy to @buf + off > + * @count: the maximum number of bytes to print > + * > + * The role of cpumap_print_to_buf and cpumap_print_to_pagebuf is cpumap_print_to_buf() + other cases of the same so that hyperlinks work in the html docs. > + * the same, the difference is that buf of bitmap_print_to_buf > + * can be more than one pagesize. > + */ > +static inline ssize_t > +cpumap_print_to_buf(bool list, char *buf, const struct cpumask *mask, > + loff_t off, size_t count) > +{ > + return bitmap_print_to_buf(list, buf, cpumask_bits(mask), > + nr_cpu_ids, off, count); > +} > + > #if NR_CPUS <= BITS_PER_LONG > #define CPU_MASK_ALL \ > (cpumask_t) { { \ > diff --git a/lib/bitmap.c b/lib/bitmap.c > index 75006c4..cb64e66 100644 > --- a/lib/bitmap.c > +++ b/lib/bitmap.c > @@ -460,6 +460,40 @@ int bitmap_parse_user(const char __user *ubuf, > EXPORT_SYMBOL(bitmap_parse_user); > > /** > + * bitmap_print_to_buf - convert bitmap to list or hex format ASCII string > + * @list: indicates whether the bitmap must be list > + * @buf: the kernel space buffer to read to > + * @maskp: pointer to bitmap to convert > + * @nmaskbits: size of bitmap, in bits > + * @off: offset in data buffer below > + * @count: the maximum number of bytes to print > + * > + * The role of bitmap_print_to_buf and bitmap_print_to_pagebuf() is > + * the same, the difference is that buf of bitmap_print_to_buf() > + * can be more than one pagesize. > + */ > +int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, > + int nmaskbits, loff_t off, size_t count) > +{ > + int size; > + void *data; > + const char *fmt = list ? "%*pbl\n" : "%*pb\n"; > + > + if (off == LLONG_MAX && count == PAGE_SIZE - offset_in_page(buf)) > + return scnprintf(buf, count, fmt, nmaskbits, maskp); > + > + data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp); > + if (!data) > + return -ENOMEM; > + > + size = memory_read_from_buffer(buf, count, &off, data, strlen(data)); strlen(data) + 1 I think... > + kfree(data); > + > + return size; > +} > +EXPORT_SYMBOL(bitmap_print_to_buf); > + > +/** > * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string > * @list: indicates whether the bitmap must be list > * @buf: page aligned buffer into which string is placed > @@ -480,8 +514,8 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp, > { > ptrdiff_t len = PAGE_SIZE - offset_in_page(buf); > > - return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) : > - scnprintf(buf, len, "%*pb\n", nmaskbits, maskp); > + return bitmap_print_to_buf(list, buf, maskp, nmaskbits, > + LLONG_MAX, len); > } > EXPORT_SYMBOL(bitmap_print_to_pagebuf); >