From patchwork Wed Jan 15 02:38:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 11333141 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 377AB921 for ; Wed, 15 Jan 2020 02:38:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 155962467A for ; Wed, 15 Jan 2020 02:38:51 +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="B8m47kZ4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729030AbgAOCiu (ORCPT ); Tue, 14 Jan 2020 21:38:50 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:38840 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728879AbgAOCit (ORCPT ); Tue, 14 Jan 2020 21:38:49 -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:Resent-Date:Resent-From :Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=t2MsvrgFyKMklh8a9GSQdPemnFwCPtSVERkAiF6+ogA=; b=B8m47kZ4X+h0DMHQn1K+2rOHkY hwLKteFLytNaxEKnzlCSBDAJz0fJXaVd/spdpfgD0HTWbcfet0LZg+hZP4G1sqBZaNQwr4R8vvEzZ o3Dv6Ei3shJPPTdAqLbFiXyNvlj5/VrpfNTgt4xD0uBSu63frPzORfwhbgpYRVDfuvGTNCORNmu63 Q6hT/xWyrtBntiw54OYBsTjk2J7buSZ/I6G6vvtTzXrbzW1rCypYEonPrY9wKI4I45WI1TMi8rp2W WLz8zHyQwCFyXamXHDqJ/NSvq/OmfNQiqOPKz2C2S0GDsUQW+cyQO3VQe+cPw/2uYQnCOA07g5pVL EiuVVrOg==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1irYZy-0008AY-2O; Wed, 15 Jan 2020 02:38:46 +0000 From: Matthew Wilcox To: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , Jeff Layton , Christoph Hellwig , Chris Mason Subject: [PATCH v2 3/9] XArray: Add xarray_for_each_range Date: Tue, 14 Jan 2020 18:38:37 -0800 Message-Id: <20200115023843.31325-4-willy@infradead.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200115023843.31325-1-willy@infradead.org> References: <20200115023843.31325-1-willy@infradead.org> MIME-Version: 1.0 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: "Matthew Wilcox (Oracle)" This function supports iterating over a range of an array. Also add documentation links for xarray_for_each_start(). Signed-off-by: Matthew Wilcox (Oracle) --- Documentation/core-api/xarray.rst | 10 ++++++---- include/linux/xarray.h | 30 ++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+), 4 deletions(-) diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index fcedc5349ace..95a732b5c848 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -94,10 +94,10 @@ calling xa_clear_mark(). You can ask whether any entry in the XArray has a particular mark set by calling xa_marked(). You can copy entries out of the XArray into a plain array by calling -xa_extract(). Or you can iterate over the present entries in -the XArray by calling xa_for_each(). You may prefer to use -xa_find() or xa_find_after() to move to the next present -entry in the XArray. +xa_extract(). Or you can iterate over the present entries in the XArray +by calling xa_for_each(), xa_for_each_start() or xa_for_each_range(). +You may prefer to use xa_find() or xa_find_after() to move to the next +present entry in the XArray. Calling xa_store_range() stores the same entry in a range of indices. If you do this, some of the other operations will behave @@ -180,6 +180,8 @@ No lock needed: Takes RCU read lock: * xa_load() * xa_for_each() + * xa_for_each_start() + * xa_for_each_range() * xa_find() * xa_find_after() * xa_extract() diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 86eecbd98e84..a06cb555fe23 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -445,6 +445,36 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) entry; \ entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT)) +/** + * xa_for_each_range() - Iterate over a portion of an XArray. + * @xa: XArray. + * @index: Index of @entry. + * @entry: Entry retrieved from array. + * @start: First index to retrieve from array. + * @last: Last index to retrieve from array. + * + * During the iteration, @entry will have the value of the entry stored + * in @xa at @index. You may modify @index during the iteration if you + * want to skip or reprocess indices. It is safe to modify the array + * during the iteration. At the end of the iteration, @entry will be set + * to NULL and @index will have a value less than or equal to max. + * + * xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have + * to handle your own locking with xas_for_each(), and if you have to unlock + * after each iteration, it will also end up being O(n.log(n)). + * xa_for_each_range() will spin if it hits a retry entry; if you intend to + * see retry entries, you should use the xas_for_each() iterator instead. + * The xas_for_each() iterator will expand into more inline code than + * xa_for_each_range(). + * + * Context: Any context. Takes and releases the RCU lock. + */ +#define xa_for_each_range(xa, index, entry, start, last) \ + for (index = start, \ + entry = xa_find(xa, &index, last, XA_PRESENT); \ + entry; \ + entry = xa_find_after(xa, &index, last, XA_PRESENT)) + /** * xa_for_each() - Iterate over present entries in an XArray. * @xa: XArray.