From patchwork Mon Feb 17 18:45:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 11387231 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DE338109A for ; Mon, 17 Feb 2020 18:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC26922B48 for ; Mon, 17 Feb 2020 18:46:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ED0OnjLT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730124AbgBQSqq (ORCPT ); Mon, 17 Feb 2020 13:46:46 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:48410 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730047AbgBQSqe (ORCPT ); Mon, 17 Feb 2020 13:46:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=DP26YoHmQVKFeLAP9Bhl6lTFH6pmN1Lp+nkcg7gbG1k=; b=ED0OnjLTGnEOOo2CZefh2G88KH 3jrEzs4VHYd1wXeUpU6HsfbK77yiq/5cy+zhME6scGgUb7JxdN+7S2/GOG2Z/qiKlQ9PPNooPIlDL OybRjdLpztJcOs3levap4q/E2MTBAw6qzkCsJmjdII63L2Pli1xrIi6t1XVfm74+zw3q/HKqpqI92 ku/YMLp3rt2u0Ir0YBDD5xB8VqqHbl17yEZkNT0jKFY8WYkS3lRvPHPHpHSy5cUS26ajALVTZAmnr JlLOA3WaW8WbFQ9Nk1AytNed39mHzG9AvcRmp2ibIg6GFMUg+LpBV8EZtkxY4LD7oQACkug45a17s 61imUM/A==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j3lPL-00058e-AJ; Mon, 17 Feb 2020 18:46:15 +0000 From: Matthew Wilcox To: linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org Subject: [PATCH v6 01/19] mm: Return void from various readahead functions Date: Mon, 17 Feb 2020 10:45:42 -0800 Message-Id: <20200217184613.19668-2-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200217184613.19668-1-willy@infradead.org> References: <20200217184613.19668-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org From: "Matthew Wilcox (Oracle)" ondemand_readahead has two callers, neither of which use the return value. That means that both ra_submit and __do_page_cache_readahead() can return void, and we don't need to worry that a present page in the readahead window causes us to return a smaller nr_pages than we ought to have. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Dave Chinner --- mm/internal.h | 8 ++++---- mm/readahead.c | 24 ++++++++++-------------- 2 files changed, 14 insertions(+), 18 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 3cf20ab3ca01..f779f058118b 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -49,18 +49,18 @@ void unmap_page_range(struct mmu_gather *tlb, unsigned long addr, unsigned long end, struct zap_details *details); -extern unsigned int __do_page_cache_readahead(struct address_space *mapping, +extern void __do_page_cache_readahead(struct address_space *mapping, struct file *filp, pgoff_t offset, unsigned long nr_to_read, unsigned long lookahead_size); /* * Submit IO for the read-ahead request in file_ra_state. */ -static inline unsigned long ra_submit(struct file_ra_state *ra, +static inline void ra_submit(struct file_ra_state *ra, struct address_space *mapping, struct file *filp) { - return __do_page_cache_readahead(mapping, filp, - ra->start, ra->size, ra->async_size); + __do_page_cache_readahead(mapping, filp, + ra->start, ra->size, ra->async_size); } /* diff --git a/mm/readahead.c b/mm/readahead.c index 2fe72cd29b47..8ce46d69e6ae 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -149,10 +149,8 @@ static int read_pages(struct address_space *mapping, struct file *filp, * the pages first, then submits them for I/O. This avoids the very bad * behaviour which would occur if page allocations are causing VM writeback. * We really don't want to intermingle reads and writes like that. - * - * Returns the number of pages requested, or the maximum amount of I/O allowed. */ -unsigned int __do_page_cache_readahead(struct address_space *mapping, +void __do_page_cache_readahead(struct address_space *mapping, struct file *filp, pgoff_t offset, unsigned long nr_to_read, unsigned long lookahead_size) { @@ -166,7 +164,7 @@ unsigned int __do_page_cache_readahead(struct address_space *mapping, gfp_t gfp_mask = readahead_gfp_mask(mapping); if (isize == 0) - goto out; + return; end_index = ((isize - 1) >> PAGE_SHIFT); @@ -211,8 +209,6 @@ unsigned int __do_page_cache_readahead(struct address_space *mapping, if (nr_pages) read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask); BUG_ON(!list_empty(&page_pool)); -out: - return nr_pages; } /* @@ -378,11 +374,10 @@ static int try_context_readahead(struct address_space *mapping, /* * A minimal readahead algorithm for trivial sequential/random reads. */ -static unsigned long -ondemand_readahead(struct address_space *mapping, - struct file_ra_state *ra, struct file *filp, - bool hit_readahead_marker, pgoff_t offset, - unsigned long req_size) +static void ondemand_readahead(struct address_space *mapping, + struct file_ra_state *ra, struct file *filp, + bool hit_readahead_marker, pgoff_t offset, + unsigned long req_size) { struct backing_dev_info *bdi = inode_to_bdi(mapping->host); unsigned long max_pages = ra->ra_pages; @@ -428,7 +423,7 @@ ondemand_readahead(struct address_space *mapping, rcu_read_unlock(); if (!start || start - offset > max_pages) - return 0; + return; ra->start = start; ra->size = start - offset; /* old async_size */ @@ -464,7 +459,8 @@ ondemand_readahead(struct address_space *mapping, * standalone, small random read * Read as is, and do not pollute the readahead state. */ - return __do_page_cache_readahead(mapping, filp, offset, req_size, 0); + __do_page_cache_readahead(mapping, filp, offset, req_size, 0); + return; initial_readahead: ra->start = offset; @@ -489,7 +485,7 @@ ondemand_readahead(struct address_space *mapping, } } - return ra_submit(ra, mapping, filp); + ra_submit(ra, mapping, filp); } /**