From patchwork Tue Jul 18 07:25:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Stanner X-Patchwork-Id: 13316815 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 E6247EB64DC for ; Tue, 18 Jul 2023 07:26:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231709AbjGRH0u (ORCPT ); Tue, 18 Jul 2023 03:26:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231655AbjGRH0q (ORCPT ); Tue, 18 Jul 2023 03:26:46 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6BF8EC for ; Tue, 18 Jul 2023 00:26:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689665163; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=a2DjjjM4FGyKHuuM5I0RdnKN+Rz/1iCrCtnKqTggf0w=; b=d5oId6SnVsywQNkuBnO5jZkLcBsuCdRET3Me4HIYFNCNOruX4tNpozQABCTyZIeixq5GXj XhiAbTZcqDjy4FhDLRFXNXCCqYjVyFVppABxCg8JQLJQNxLw4kiPybchrlPjyiJMj4Uotw y8GF+nD5BVqLL4hM4iTbgpnGb8L1VUk= Received: from mail-ej1-f69.google.com (mail-ej1-f69.google.com [209.85.218.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-195-iBgJyNXFMd2Bc7GWA-cV6w-1; Tue, 18 Jul 2023 03:25:59 -0400 X-MC-Unique: iBgJyNXFMd2Bc7GWA-cV6w-1 Received: by mail-ej1-f69.google.com with SMTP id a640c23a62f3a-993b803c391so60399066b.1 for ; Tue, 18 Jul 2023 00:25:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689665158; x=1690269958; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=a2DjjjM4FGyKHuuM5I0RdnKN+Rz/1iCrCtnKqTggf0w=; b=hoK7j7IsjJEHvqExsxgY1u9dZJl7eC8+GGr1hKqEQLQtx2fra69mXVY9yh6CVUxhEQ cQVk/0PpyzK9ouIw/kpH5GTEuacjz2M78bwPjScAVEe9/YczJo+wXI+EU8Tiy5yI38Wo iOqvYSqyOsiByNxZS/HqUJJWsc8ir8Vt90PyV25Xcn7QcPlYxYpacrs+J10d1xbNVD3D G1lp92l7Rm8i+9gJNN5WbiNuTWbUDG6UjBJBo9+TvmWwoPFDII9ZQ6Skj997WAFSwtc6 CPiAw+g+28X1XE7G7pAmlSVJv7tZErTC+cjiyKZio1RxPcB6apmtlwLV4ziaN/vsAG7q Y21Q== X-Gm-Message-State: ABy/qLauN9w44CrXTdirhFjbtyaRfLmHuuYaE0eUFQTqPxgw8KDbwKwA CNkFgxO4y+Gwui8Fid0TouDOa+08fLhE4rZuFHa8I7mihZwM/BiSmEhUHu5CS4jSv7AMBjggxfw JuqeEXwqAkS/jyMILe+ourWHA1w== X-Received: by 2002:a17:906:54:b0:993:f349:c989 with SMTP id 20-20020a170906005400b00993f349c989mr10269303ejg.7.1689665158577; Tue, 18 Jul 2023 00:25:58 -0700 (PDT) X-Google-Smtp-Source: APBJJlGrcxToIhvi9pZkYvgvkHEy7/T+z+0ZGTKH6gDMN7h9Tf78M3vRIMAt9t7XyJ2PXGXp2U1Bjw== X-Received: by 2002:a17:906:54:b0:993:f349:c989 with SMTP id 20-20020a170906005400b00993f349c989mr10269288ejg.7.1689665158219; Tue, 18 Jul 2023 00:25:58 -0700 (PDT) Received: from fedora.fritz.box ([2001:9e8:32ec:1b00:f440:b055:3d37:de8]) by smtp.gmail.com with ESMTPSA id n10-20020a170906378a00b00992025654c1sm632721ejc.179.2023.07.18.00.25.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Jul 2023 00:25:57 -0700 (PDT) From: Philipp Stanner To: willy@infradead.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Philipp Stanner Subject: [PATCH v2] xarray: Document necessary flag in alloc functions Date: Tue, 18 Jul 2023 09:25:34 +0200 Message-ID: <20230718072533.4305-2-pstanner@redhat.com> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Adds a new line to the docstrings of functions wrapping __xa_alloc() and __xa_alloc_cyclic(), informing about the necessity of flag XA_FLAGS_ALLOC being set previously. The documentation so far says that functions wrapping __xa_alloc() and __xa_alloc_cyclic() are supposed to return either -ENOMEM or -EBUSY in case of an error. If the xarray has been initialized without the flag XA_FLAGS_ALLOC, however, they fail with a different, undocumented error code. As hinted at in Documentation/core-api/xarray.rst, wrappers around these functions should only be invoked when the flag has been set. The functions' documentation should reflect that as well. Signed-off-by: Philipp Stanner --- Version 2 of the proposed documentation update. As Matthew requested, I added the sentence to all functions wrapping the above mentioned two core functions. Additionally, I added it to themselves, too, as these functions can also be called by the user directly. I also rephrased the commit message so that the implemented change is mentioned first. --- include/linux/xarray.h | 18 ++++++++++++++++++ lib/xarray.c | 6 ++++++ 2 files changed, 24 insertions(+) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 741703b45f61..cb571dfcf4b1 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -856,6 +856,9 @@ static inline int __must_check xa_insert_irq(struct xarray *xa, * stores the index into the @id pointer, then stores the entry at * that index. A concurrent lookup will not see an uninitialised @id. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Any context. Takes and releases the xa_lock. May sleep if * the @gfp flags permit. * Return: 0 on success, -ENOMEM if memory could not be allocated or @@ -886,6 +889,9 @@ static inline __must_check int xa_alloc(struct xarray *xa, u32 *id, * stores the index into the @id pointer, then stores the entry at * that index. A concurrent lookup will not see an uninitialised @id. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Any context. Takes and releases the xa_lock while * disabling softirqs. May sleep if the @gfp flags permit. * Return: 0 on success, -ENOMEM if memory could not be allocated or @@ -916,6 +922,9 @@ static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id, * stores the index into the @id pointer, then stores the entry at * that index. A concurrent lookup will not see an uninitialised @id. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Process context. Takes and releases the xa_lock while * disabling interrupts. May sleep if the @gfp flags permit. * Return: 0 on success, -ENOMEM if memory could not be allocated or @@ -949,6 +958,9 @@ static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id, * The search for an empty entry will start at @next and will wrap * around if necessary. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Any context. Takes and releases the xa_lock. May sleep if * the @gfp flags permit. * Return: 0 if the allocation succeeded without wrapping. 1 if the @@ -983,6 +995,9 @@ static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, * The search for an empty entry will start at @next and will wrap * around if necessary. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Any context. Takes and releases the xa_lock while * disabling softirqs. May sleep if the @gfp flags permit. * Return: 0 if the allocation succeeded without wrapping. 1 if the @@ -1017,6 +1032,9 @@ static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry, * The search for an empty entry will start at @next and will wrap * around if necessary. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Process context. Takes and releases the xa_lock while * disabling interrupts. May sleep if the @gfp flags permit. * Return: 0 if the allocation succeeded without wrapping. 1 if the diff --git a/lib/xarray.c b/lib/xarray.c index 2071a3718f4e..73b3f8b33a56 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1802,6 +1802,9 @@ EXPORT_SYMBOL(xa_get_order); * stores the index into the @id pointer, then stores the entry at * that index. A concurrent lookup will not see an uninitialised @id. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Any context. Expects xa_lock to be held on entry. May * release and reacquire xa_lock if @gfp flags permit. * Return: 0 on success, -ENOMEM if memory could not be allocated or @@ -1850,6 +1853,9 @@ EXPORT_SYMBOL(__xa_alloc); * The search for an empty entry will start at @next and will wrap * around if necessary. * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * * Context: Any context. Expects xa_lock to be held on entry. May * release and reacquire xa_lock if @gfp flags permit. * Return: 0 if the allocation succeeded without wrapping. 1 if the