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=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED 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 54BFCC5CFC0 for ; Sun, 17 Jun 2018 02:08:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 115FA2086A for ; Sun, 17 Jun 2018 02:08:33 +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="enZlbfI9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 115FA2086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936494AbeFQCIF (ORCPT ); Sat, 16 Jun 2018 22:08:05 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:59240 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933978AbeFQCBK (ORCPT ); Sat, 16 Jun 2018 22:01:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding: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=6CtH22NpoaemDSFVaBuH/UKCnAIo12i5SDA7CsPpPB8=; b=enZlbfI9wXXz6+EBEkFiy9m/k kt+C1t9v+DOjsgRjSlROOtXSExB0JfbGElKzRRlkpDixFmAsj7NqoYl2vkaNRaAV9e2qsBLbawMd7 2V+NPrpcpZr6Tz9vH6txcgm1gsZQEthoYzoWVpuIbZN9iKx8Nczisl6Kf7ODKpnWM5U4nNqJUzKQU k2dxk7v2a30hWRXlDFVIobiPkbwfGy5H5+5On4MFGEIG4gDqydppCgcT8oHofRynWzWHq3ynIWJKE yI4DbKG1dLpTYowlYpBvwZBWXNe7JCH1ajp+0EW+pTITfO03ovzN3TENi+EQ8pMTkW4/YaYTdvDrE 75myFGVhg==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1fUMzw-0001GS-Lp; Sun, 17 Jun 2018 02:00:56 +0000 From: Matthew Wilcox To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Matthew Wilcox , Jan Kara , Jeff Layton , Lukas Czerner , Ross Zwisler , Christoph Hellwig , Goldwyn Rodrigues , Nicholas Piggin , Ryusuke Konishi , linux-nilfs@vger.kernel.org, Jaegeuk Kim , Chao Yu , linux-f2fs-devel@lists.sourceforge.net Subject: [PATCH v14 14/74] xarray: Extract entries from an XArray Date: Sat, 16 Jun 2018 18:59:52 -0700 Message-Id: <20180617020052.4759-15-willy@infradead.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180617020052.4759-1-willy@infradead.org> References: <20180617020052.4759-1-willy@infradead.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The xa_extract function combines the functionality of radix_tree_gang_lookup() and radix_tree_gang_lookup_tagged(). It extracts entries matching the specified filter into a normal array. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 2 ++ lib/xarray.c | 80 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 82 insertions(+) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 0790b3b098f0..6f398732b664 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -227,6 +227,8 @@ void *xa_find(struct xarray *xa, unsigned long *index, unsigned long max, xa_tag_t) __attribute__((nonnull(2))); void *xa_find_after(struct xarray *xa, unsigned long *index, unsigned long max, xa_tag_t) __attribute__((nonnull(2))); +unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, + unsigned long max, unsigned int n, xa_tag_t); /** * xa_init() - Initialise an empty XArray. diff --git a/lib/xarray.c b/lib/xarray.c index 8756ca22363e..1e15ead40d78 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1413,6 +1413,86 @@ void *xa_find_after(struct xarray *xa, unsigned long *indexp, } EXPORT_SYMBOL(xa_find_after); +static unsigned int xas_extract_present(struct xa_state *xas, void **dst, + unsigned long max, unsigned int n) +{ + void *entry; + unsigned int i = 0; + + rcu_read_lock(); + xas_for_each(xas, entry, max) { + if (xas_retry(xas, entry)) + continue; + dst[i++] = entry; + if (i == n) + break; + } + rcu_read_unlock(); + + return i; +} + +static unsigned int xas_extract_tag(struct xa_state *xas, void **dst, + unsigned long max, unsigned int n, xa_tag_t tag) +{ + void *entry; + unsigned int i = 0; + + rcu_read_lock(); + xas_for_each_tagged(xas, entry, max, tag) { + if (xas_retry(xas, entry)) + continue; + dst[i++] = entry; + if (i == n) + break; + } + rcu_read_unlock(); + + return i; +} + +/** + * xa_extract() - Copy selected entries from the XArray into a normal array. + * @xa: The source XArray to copy from. + * @dst: The buffer to copy entries into. + * @start: The first index in the XArray eligible to be selected. + * @max: The last index in the XArray eligible to be selected. + * @n: The maximum number of entries to copy. + * @filter: Selection criterion. + * + * Copies up to @n entries that match @filter from the XArray. The + * copied entries will have indices between @start and @max, inclusive. + * + * The @filter may be an XArray tag value, in which case entries which are + * tagged with that tag will be copied. It may also be %XA_PRESENT, in + * which case non-NULL entries will be copied. + * + * The entries returned may not represent a snapshot of the XArray at a + * moment in time. For example, if another thread stores to index 5, then + * index 10, calling xa_extract() may return the old contents of index 5 + * and the new contents of index 10. Indices not modified while this + * function is running will not be skipped. + * + * If you need stronger guarantees, holding the xa_lock across calls to this + * function will prevent concurrent modification. + * + * Context: Any context. Takes and releases the RCU lock. + * Return: The number of entries copied. + */ +unsigned int xa_extract(struct xarray *xa, void **dst, unsigned long start, + unsigned long max, unsigned int n, xa_tag_t filter) +{ + XA_STATE(xas, xa, start); + + if (!n) + return 0; + + if ((__force unsigned int)filter < XA_MAX_TAGS) + return xas_extract_tag(&xas, dst, max, n, filter); + return xas_extract_present(&xas, dst, max, n); +} +EXPORT_SYMBOL(xa_extract); + #ifdef XA_DEBUG void xa_dump_node(const struct xa_node *node) { -- 2.17.1