From patchwork Tue Aug 29 14:25:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Philipp Stanner X-Patchwork-Id: 13369079 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 3F72BC6FA8F for ; Tue, 29 Aug 2023 14:26:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233034AbjH2O0G (ORCPT ); Tue, 29 Aug 2023 10:26:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236963AbjH2OZ4 (ORCPT ); Tue, 29 Aug 2023 10:25:56 -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 CE336AB for ; Tue, 29 Aug 2023 07:25:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693319107; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=72jjJIsr12NXRU7aDK4GbDjvA7ef38LcvCbu/brjroY=; b=jM1uH5au6IDpdLsmKPLzAAFD3ShGhBl7TKjLxUEUV3H4NgWhQ1eYfg7KGYr97Aga53nDiG WUE92JeKl6mK8vKbZXxtB86epVVHJMkB2lbsL1PbBy82XV9EclJwDYPzNhpfe8X23bUUc2 sjFK8knsaIf1QQ1Uq9MzPg0XzVVkWA4= Received: from mail-ej1-f72.google.com (mail-ej1-f72.google.com [209.85.218.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-107-wtVE9DrCNKGX2Z_VT7fiSQ-1; Tue, 29 Aug 2023 10:25:05 -0400 X-MC-Unique: wtVE9DrCNKGX2Z_VT7fiSQ-1 Received: by mail-ej1-f72.google.com with SMTP id a640c23a62f3a-9a1c4506e1eso68502366b.1 for ; Tue, 29 Aug 2023 07:25:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693319104; x=1693923904; h=mime-version:user-agent:content-transfer-encoding:date:cc:to:from :subject:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=72jjJIsr12NXRU7aDK4GbDjvA7ef38LcvCbu/brjroY=; b=OEfvd6qo7wukEmJbgAlHp6ja6RilvKHBwCEZtgtMIVRNoyWuO2gcyueimStBnVX1ws nR6PuaslYQPAJGKxBCTUuNbwVvLE7Z8kbdXag04o9VfVTTgotzkuOdRp0QM24z5UPmmU 0WnxCaDIuPscnZf5hcKEIYjVvM4uJhelvDqWgSY1EO2dtHgLmxjvSz0iMK2TDCZVE/YL /gZRMP6VRkOmveTYSuMG4CGhbCdZwng0XEeXz0B/YDpmfru7n9ryPf4SXNjlx68z5wer Br6XvCfY/5nT14P7Ibl98rF7qFKp9L5a4PqZ8vzXDtc+XGuUCa0kHSHoijmkKSGwWZ/A a8Tg== X-Gm-Message-State: AOJu0YzKZgZDZ1Y8J/xeQWdypZeBC7TjGObt7gS0W3LlolM8oMbMaoPw 7IsJ/9xgn+k0Z/y5HmRIu7bA5JlUHKHoAnBaSaydNsxTd3X4KndwuZR6CgcD0B6cXIigOuRSA+t iaT0hfFD6/bOdADIABtONOkyXlw== X-Received: by 2002:a17:906:257:b0:9a1:eb67:c0d2 with SMTP id 23-20020a170906025700b009a1eb67c0d2mr12931439ejl.6.1693319104109; Tue, 29 Aug 2023 07:25:04 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHKi2VXt+Ovw7zv8607SLKgZhnUivVO6erEvkOL/iqaS7Wn9pyraiegUPmPO3FzcCzxQroolQ== X-Received: by 2002:a17:906:257:b0:9a1:eb67:c0d2 with SMTP id 23-20020a170906025700b009a1eb67c0d2mr12931432ejl.6.1693319103814; Tue, 29 Aug 2023 07:25:03 -0700 (PDT) Received: from ?IPv6:2001:9e8:32d7:ba00:5749:c26e:a109:dac4? ([2001:9e8:32d7:ba00:5749:c26e:a109:dac4]) by smtp.gmail.com with ESMTPSA id lv12-20020a170906bc8c00b009a19701e7b5sm6015949ejb.96.2023.08.29.07.25.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Aug 2023 07:25:03 -0700 (PDT) Message-ID: Subject: [RESEND PATCH v2] xarray: Document necessary flag in alloc functions From: pstanner@redhat.com To: willy@infradead.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Philipp Stanner Date: Tue, 29 Aug 2023 16:25:02 +0200 User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) 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