From patchwork Wed Feb 19 21:01:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 1241003 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=Ez8O6Ork; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48N9CX084pz9sSK for ; Thu, 20 Feb 2020 08:02:32 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727827AbgBSVBG (ORCPT ); Wed, 19 Feb 2020 16:01:06 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:35914 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727592AbgBSVBF (ORCPT ); Wed, 19 Feb 2020 16:01:05 -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=erFAlFt7URKao+s7h4ENpLN+DsCi0u0lEGbwZPr/bFo=; b=Ez8O6Ork4eM5HUZAaYjx52rH2y 4lieoM83EpQuWgejFeMJRSD3vAz098TXGV3I4kOGIMPFYhkczKgk6r9ev9aYcBhMFWPV6Su87WcUF WzSqnxWhPQiSIvNFy5wvbWQhLCuGo9rdjXrglVVZc7aTNjzUc/1VxOBxvY8ksQWBNs/tDWxUValZ1 zNq6IQcJoXKrO93oWsp6x6tqa7v5Isrcub5czeYkk+HLGrOV9JhvQ0pR1hBiIFm6SO1MVW4+xqzj5 +lcM2cyaeBfGc9H2MieqJ+y/i/uohPEyQx9bwMAqtRJz0AdumNavA7uQpYKgL2AAcn9oHSYzFN/fi bCsNsoYg==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j4WSv-0008VK-Gt; Wed, 19 Feb 2020 21:01:05 +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 v7 21/24] iomap: Restructure iomap_readpages_actor Date: Wed, 19 Feb 2020 13:01:00 -0800 Message-Id: <20200219210103.32400-22-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200219210103.32400-1-willy@infradead.org> References: <20200219210103.32400-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: "Matthew Wilcox (Oracle)" By putting the 'have we reached the end of the page' condition at the end of the loop instead of the beginning, we can remove the 'submit the last page' code from iomap_readpages(). Also check that iomap_readpage_actor() didn't return 0, which would lead to an endless loop. Signed-off-by: Matthew Wilcox (Oracle) --- fs/iomap/buffered-io.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index cb3511eb152a..31899e6cb0f8 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -400,15 +400,9 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap, struct iomap *srcmap) { struct iomap_readpage_ctx *ctx = data; - loff_t done, ret; - - for (done = 0; done < length; done += ret) { - if (ctx->cur_page && offset_in_page(pos + done) == 0) { - if (!ctx->cur_page_in_bio) - unlock_page(ctx->cur_page); - put_page(ctx->cur_page); - ctx->cur_page = NULL; - } + loff_t ret, done = 0; + + while (done < length) { if (!ctx->cur_page) { ctx->cur_page = iomap_next_page(inode, ctx->pages, pos, length, &done); @@ -418,6 +412,20 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, } ret = iomap_readpage_actor(inode, pos + done, length - done, ctx, iomap, srcmap); + done += ret; + + /* Keep working on a partial page */ + if (ret && offset_in_page(pos + done)) + continue; + + if (!ctx->cur_page_in_bio) + unlock_page(ctx->cur_page); + put_page(ctx->cur_page); + ctx->cur_page = NULL; + + /* Don't loop forever if we made no progress */ + if (WARN_ON(!ret)) + break; } return done; @@ -451,11 +459,7 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages, done: if (ctx.bio) submit_bio(ctx.bio); - if (ctx.cur_page) { - if (!ctx.cur_page_in_bio) - unlock_page(ctx.cur_page); - put_page(ctx.cur_page); - } + BUG_ON(ctx.cur_page); /* * Check that we didn't lose a page due to the arcance calling