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 A9922C433EF for ; Wed, 9 Mar 2022 13:51:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233328AbiCINwQ (ORCPT ); Wed, 9 Mar 2022 08:52:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233094AbiCINwP (ORCPT ); Wed, 9 Mar 2022 08:52:15 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD19217C40D for ; Wed, 9 Mar 2022 05:51:15 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 6C4A31F381; Wed, 9 Mar 2022 13:51:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1646833874; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NyySmuqnqYuvobZ2m4gcmSuN3zGMKKqHyk7RTxG+zUM=; b=pO0mwo2pnJtbLhowDFua1hcZ8opHLDVN8AoVcZ8cJUpPy8XkB+SjGcB2zpwGE1jJ2bUgDo GHvzHEpGmFkzJDYStKbbs62vZJx56jg18vuAf3LmcDe9tfwIEb/yuqeIv2uVvdABcMr/l7 t+8deNkQYwofYjGcGvA7ZyrtmfXzspU= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 3C6DD13D7A; Wed, 9 Mar 2022 13:51:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id SAtADdKwKGL1LQAAMHmgww (envelope-from ); Wed, 09 Mar 2022 13:51:14 +0000 From: Gabriel Niebler To: linux-btrfs@vger.kernel.org Cc: dsterba@suse.com, Gabriel Niebler , Marcos Paulo de Souza Subject: [PATCH v4 01/14] btrfs: Introduce btrfs_for_each_slot iterator macro Date: Wed, 9 Mar 2022 14:50:38 +0100 Message-Id: <20220309135051.5738-2-gniebler@suse.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220309135051.5738-1-gniebler@suse.com> References: <20220309135051.5738-1-gniebler@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org There is a common pattern when searching for a key in btrfs: * Call btrfs_search_slot to find the slot for the key * Enter an endless loop: * If the found slot is larger than the no. of items in the current leaf, check the next leaf * If it's still not found in the next leaf, terminate the loop * Otherwise do something with the found key * Increment the current slot and continue To reduce code duplication, we can replace this code pattern with an iterator macro, similar to the existing for_each_X macros found elsewhere in the kernel. This also makes the code easier to understand for newcomers by putting a name to the encapsulated functionality. Signed-off-by: Marcos Paulo de Souza Signed-off-by: Gabriel Niebler --- fs/btrfs/ctree.c | 35 +++++++++++++++++++++++++++++++++++ fs/btrfs/ctree.h | 25 +++++++++++++++++++++++++ 2 files changed, 60 insertions(+) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index a7db3f6f1b7b..13f1011bf2b4 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2277,6 +2277,41 @@ int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, return ret; } +/* + * Search for a valid slot for the given path. + * + * @root: The root node of the tree. + * @key: Will contain a valid item if found. + * @path: The starting point to validate the slot. + * + * Return 0 if the item is valid, 1 if not found and < 0 if error. + */ +int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, + struct btrfs_path *path) +{ + while (1) { + int ret; + const int slot = path->slots[0]; + const struct extent_buffer *leaf = path->nodes[0]; + + /* This is where we start walking through the path. */ + if (slot >= btrfs_header_nritems(leaf)) { + /* + * If we've reached the last slot in this leaf we need + * to go to the next leaf and reset the path. + */ + ret = btrfs_next_leaf(root, path); + if (ret) + return ret; + continue; + } + /* Store the found, valid item in @key. */ + btrfs_item_key_to_cpu(leaf, key, slot); + break; + } + return 0; +} + /* * adjust the pointers going up the tree, starting at level * making sure the right key of each node is points to 'key'. diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index ebb2d109e8bb..5bacfa69457c 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -2986,6 +2986,31 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path, int btrfs_search_backwards(struct btrfs_root *root, struct btrfs_key *key, struct btrfs_path *path); +int btrfs_get_next_valid_item(struct btrfs_root *root, struct btrfs_key *key, + struct btrfs_path *path); + +/* + * Search in @root for a given @key, and store the slot found in @found_key. + * + * @root: The root node of the tree. + * @key: The key we are looking for. + * @found_key: Will hold the found item. + * @path: Holds the current slot/leaf. + * @iter_ret: Contains the value returned from btrfs_search_slot or + * btrfs_get_next_valid_item, whichever was executed last. + * + * The iter_ret is an output variable that will contain the return value of + * btrfs_search_slot, if it encountered an error, or the value returned from + * btrfs_get_next_valid_item, otherwise. That return value can be 0, if a valid + * slot was found, 1 if there were no more leaves, and <0 if there was an error. + */ +#define btrfs_for_each_slot(root, key, found_key, path, iter_ret) \ + for (iter_ret = btrfs_search_slot(NULL, (root), (key), (path), 0, 0); \ + (iter_ret) >= 0 && \ + (iter_ret = btrfs_get_next_valid_item((root), (found_key), (path))) == 0; \ + (path)->slots[0]++ \ + ) + static inline int btrfs_next_old_item(struct btrfs_root *root, struct btrfs_path *p, u64 time_seq) { -- 2.35.1