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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A09F2C77B6E for ; Fri, 14 Apr 2023 13:06:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229937AbjDNNGr (ORCPT ); Fri, 14 Apr 2023 09:06:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229497AbjDNNGp (ORCPT ); Fri, 14 Apr 2023 09:06:45 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9BD48F; Fri, 14 Apr 2023 06:06:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ov9Nv07vd2ONH43CkakQ5l8x67Im3l3yCqIZ1sqEEJk=; b=IwvUrl7tORipAsI0Ov77Oqy48t 85/Ml2o5mzC0vuExBMNJhHiEtFWLdvxySaqlrkvZuE2a6iIlYk9wxgTr8uFu4XUOAkBwLWPZX27GJ NUnt7k2cBbT6k33Xzb6u4rmbsxTEHKxu/jdqdRjeBAGeNdKs21xjxyz/yddGIdnw4a/t1aQf0yN4F SgMWovBo/GBkoN0VgkzTSa7h38JrYMnI/8ORybSCZnZ4zFwENyxeXyrx1t+nnoY6Zi9bGrpfaHBXH 2jirsa+RgpGByNJHSpE0ygsglhv/0Y0G/eaxGkmFa7N8Q2sjN+wbonmoOmZh2JwhYhQDRk0lami34 Y7TF7/cw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pnJ8L-008lSJ-KC; Fri, 14 Apr 2023 13:06:33 +0000 Date: Fri, 14 Apr 2023 14:06:33 +0100 From: Matthew Wilcox To: Pankaj Raghav Cc: brauner@kernel.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mcgrof@kernel.org, gost.dev@samsung.com, hare@suse.de Subject: Re: [RFC 2/4] buffer: add alloc_folio_buffers() helper Message-ID: References: <20230414110821.21548-1-p.raghav@samsung.com> <20230414110821.21548-3-p.raghav@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230414110821.21548-3-p.raghav@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 14, 2023 at 01:08:19PM +0200, Pankaj Raghav wrote: > Folio version of alloc_page_buffers() helper. This is required to convert > create_page_buffers() to create_folio_buffers() later in the series. > > It removes one call to compound_head() compared to alloc_page_buffers(). I would convert alloc_page_buffers() to folio_alloc_buffers() and add static struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, bool retry) { return folio_alloc_buffers(page_folio(page), size, retry); } in buffer_head.h (there are only five callers, so this feels like a better tradeoff than creating a new function) > Signed-off-by: Pankaj Raghav > --- > fs/buffer.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 59 insertions(+) > > diff --git a/fs/buffer.c b/fs/buffer.c > index 44380ff3a31f..0f9c2127543d 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -900,6 +900,65 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, > } > EXPORT_SYMBOL_GPL(alloc_page_buffers); > > +/* > + * Create the appropriate buffers when given a folio for data area and > + * the size of each buffer.. Use the bh->b_this_page linked list to > + * follow the buffers created. Return NULL if unable to create more > + * buffers. > + * > + * The retry flag is used to differentiate async IO (paging, swapping) > + * which may not fail from ordinary buffer allocations. > + */ > +struct buffer_head *alloc_folio_buffers(struct folio *folio, unsigned long size, > + bool retry) > +{ > + struct buffer_head *bh, *head; > + gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT; > + long offset; > + struct mem_cgroup *memcg, *old_memcg; > + > + if (retry) > + gfp |= __GFP_NOFAIL; > + > + /* The folio lock pins the memcg */ > + memcg = folio_memcg(folio); > + old_memcg = set_active_memcg(memcg); > + > + head = NULL; > + offset = folio_size(folio); > + while ((offset -= size) >= 0) { > + bh = alloc_buffer_head(gfp); > + if (!bh) > + goto no_grow; > + > + bh->b_this_page = head; > + bh->b_blocknr = -1; > + head = bh; > + > + bh->b_size = size; > + > + /* Link the buffer to its folio */ > + set_bh_folio(bh, folio, offset); > + } > +out: > + set_active_memcg(old_memcg); > + return head; > +/* > + * In case anything failed, we just free everything we got. > + */ > +no_grow: > + if (head) { > + do { > + bh = head; > + head = head->b_this_page; > + free_buffer_head(bh); > + } while (head); > + } > + > + goto out; > +} > +EXPORT_SYMBOL_GPL(alloc_folio_buffers); > + > static inline void > link_dev_buffers(struct page *page, struct buffer_head *head) > { > -- > 2.34.1 >