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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAA1FC369C2 for ; Wed, 16 Apr 2025 14:28:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CD6A0280128; Wed, 16 Apr 2025 10:28:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C8474280126; Wed, 16 Apr 2025 10:28:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B4966280128; Wed, 16 Apr 2025 10:28:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 95405280126 for ; Wed, 16 Apr 2025 10:28:48 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 8FDC3140964 for ; Wed, 16 Apr 2025 14:28:48 +0000 (UTC) X-FDA: 83340138336.10.409F59C Received: from mail-lf1-f47.google.com (mail-lf1-f47.google.com [209.85.167.47]) by imf01.hostedemail.com (Postfix) with ESMTP id 8AED540011 for ; Wed, 16 Apr 2025 14:28:46 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="Vc/IE45F"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf01.hostedemail.com: domain of urezki@gmail.com designates 209.85.167.47 as permitted sender) smtp.mailfrom=urezki@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1744813726; a=rsa-sha256; cv=none; b=xEjm1lC/JmvgbwJcEy+DNx8whFRhGUh7t/6T05FbQ/khYXctsng5r3oiOcxVQfFH+2VSCu nAzmVuIjK0QTMH1zr8q1cwapR8HFfTlmwttIYdq7h8xhmgmu9v8pxSdq3uXyfNjKTyueHI IlCC6vgGbOLl5dxHagSBqCiBFqt+xec= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b="Vc/IE45F"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf01.hostedemail.com: domain of urezki@gmail.com designates 209.85.167.47 as permitted sender) smtp.mailfrom=urezki@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1744813726; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=3kyW/XsCpCzvhbHUFh2dTXvyn07Nk4P1pRXH/bo59qM=; b=5qZwkLWs0gFtJLkj0eR5QAqQmETNjJaiz1jid4ku/FWy5cg1ihcGbtWvNtR/gKogBu4vFQ 0RgffWIMZvU87w5GdvGIdcp2pR6eRcgvGcF0M4/osnx+3gkAOn4OxVp3FXaScktKlNVsTH G5vrvSDhBBqnlIF3k1ilblTsTGKOrD8= Received: by mail-lf1-f47.google.com with SMTP id 2adb3069b0e04-54c0fa6d455so7915444e87.1 for ; Wed, 16 Apr 2025 07:28:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1744813724; x=1745418524; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=3kyW/XsCpCzvhbHUFh2dTXvyn07Nk4P1pRXH/bo59qM=; b=Vc/IE45F2AWI9ObsNIqxJqKETZsCBrBYjq/uDuGdA1daLhxCLOsxz91KPmor3AayWR EOvc2Xneo38y7nPQZROw1MqP74KFQ0DgISi8+CwUZvw+PuwYSI4ks2cRwELlNTxtIEIh Oa6kB41AR0ytqK71rPzSso5Hl+YHpt61632YhoQ2HX1hgYQaZ7dIo/XoquWPHGVbXY3W BuVkKmxfUtAYaIlkOWDKhs5YrGyN4qNvbcufDI0T/rhhR7JHsZzTKomzfiBa3tdDuPYh tyAvB4Qjzl7BMo2YJWoQbrnIeP9gxFRAhVhbTsCrdbvze9TZkW/oWDxba4Yp5pEjR65r 5Ykw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744813724; x=1745418524; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=3kyW/XsCpCzvhbHUFh2dTXvyn07Nk4P1pRXH/bo59qM=; b=IKSS2fwx7FSM4qwi8WbktwxTfhW1I4IAHRAajd2zLNdXk3ExmxOZGLEAwUn26t3UkA 8J8E7zIprXgWex+i14vWe1jObctaggcu/mcNrneMnCKBqfy0p83TMY+VcAvXs7bA5VOe MRmoVIvC8eURU1+d+GpbKEhDnmrgCScw8jlhKgt+lkLMZImchLxydZ0gIUvEeU6HaY3f zkopbaQ7FBlSYdk5k1Yw+AgRpowbJfeIVCMNlTCmObn/DZU6DTNeq21JsW2xt8xRwK86 8Id7+BL1BSeNbFc2fB8HQw9/GZU1q2prnVNDfANjLyDryWfZssqwsnJ0jXft1dZrUnM6 0/oA== X-Gm-Message-State: AOJu0YysdHtd+xWMmMA3R07wvySP73DhxHKbxFRKqVF+bxg+UsMQ4wGC p8JR1xqoneYX/rYMphM0eyykcHBg8RWmo1WIwFoeo6yVNHjObqbW X-Gm-Gg: ASbGncshF6D/td6eOUXstXqjyLtsCn4Mlt0d3JGN0G8NsRhNrgHBWxMHKRLifcWCqHI FYa7sYtT8d8KqoS3NQU/e3vcp+kwpK/9eZrXdVKD44kz6HJdJ7U9oLIrO9ZhzU920XsN1z1BShe gGc64InC1xNVTg8GhvvQbi3+O+Ze7kacHYgCj63Ezmnw8qume23DiNeMZHvxDvfmEd6+sPg4d/D JrWXHGaxvm13nEc83FROxHyELg+XbCiRHe/9lDv3AZ8JIPlQBJj+VDHoaqr5Q2T7qRbbxX/C4uI dobAcmFEqb2eZYUfvMr7mYgLKSvyIpMLXpe2MfVP7wuNlD+bgszWV3Qdg4CjLYj66km1 X-Google-Smtp-Source: AGHT+IG1/FK8wn68GgtHVXwCCIRHOtuozJgWvmPbSfomD+QfGzJGIid2SP4QeeIOcnPu29qdAOxlqg== X-Received: by 2002:a05:6512:2310:b0:545:8f0:e1a4 with SMTP id 2adb3069b0e04-54d64ae848fmr694308e87.45.1744813724162; Wed, 16 Apr 2025 07:28:44 -0700 (PDT) Received: from pc636 (host-90-233-217-52.mobileonline.telia.com. [90.233.217.52]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-54d3d503d08sm1679026e87.135.2025.04.16.07.28.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Apr 2025 07:28:43 -0700 (PDT) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Wed, 16 Apr 2025 16:28:41 +0200 To: Baoquan He Cc: linux-mm@kvack.org, akpm@linux-foundation.org, urezki@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/5] mm/vmalloc.c: return explicit error value in alloc_vmap_area() Message-ID: References: <20250415023952.27850-1-bhe@redhat.com> <20250415023952.27850-6-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250415023952.27850-6-bhe@redhat.com> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 8AED540011 X-Stat-Signature: 1zj9366o48rpacmx3qzu85e1xbrgnz33 X-HE-Tag: 1744813726-508505 X-HE-Meta: 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 8j0fVYIQ zZf68PqoR9r1sp7dQOqdj7m9Vqx6UHHdWYTMlskVNxCKm3k/dyk5lLOV2X1TrVtA6qIWp60eK/bDRx2qcqZAWpu2HZ1iBCS4XPq9p4tao1F2tfEEDw03ng8cOSZL2u76d8gI0oJLuhOSIF1C4KGaNS/2QdTnudVEsCWT1KeWC57aVfnW/OuybA0VJiuHssh+1+snApfmFRD/KTQYhL6tO63sxqeuSxyiufIvJTelKY88u4P2Di1IQ39J0C8AxKwhd3zX51/NX5ELI1J/E5SGlujVVDWSiaXYl2l0PzyQR31Rw3PR48BZ0VEasMCh5n0WD9XR+HTQs6x4YnWZO43BTkgrQxR8ubkvDg9U/US5XidbsFgc6vZEFp3FrIGx5AvOjm9xe4788SFI0WjBt5eGOUnGjqZIUpVMeouB7QEL9+6GR2Jc1qAHhRDjtry1I2W0KpY4H53SrWiPtRezFxerKJ1f7/g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Apr 15, 2025 at 10:39:52AM +0800, Baoquan He wrote: > In codes of alloc_vmap_area(), it returns the upper bound 'vend' to > indicate if the allocation is successful or failed. That is not very clear. > > Here change to return explicit error values and check them to judge if > allocation is successful. > > IS_ERR_VALUE already uses unlikely() internally > > Signed-off-by: Baoquan He > --- > mm/vmalloc.c | 34 +++++++++++++++++----------------- > 1 file changed, 17 insertions(+), 17 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 3f38a232663b..5b21cd09b2b4 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1715,7 +1715,7 @@ va_clip(struct rb_root *root, struct list_head *head, > */ > lva = kmem_cache_alloc(vmap_area_cachep, GFP_NOWAIT); > if (!lva) > - return -1; > + return -ENOMEM; > } > > /* > @@ -1729,7 +1729,7 @@ va_clip(struct rb_root *root, struct list_head *head, > */ > va->va_start = nva_start_addr + size; > } else { > - return -1; > + return -EINVAL; > } > > if (type != FL_FIT_TYPE) { > @@ -1758,19 +1758,19 @@ va_alloc(struct vmap_area *va, > > /* Check the "vend" restriction. */ > if (nva_start_addr + size > vend) > - return vend; > + return -ERANGE; > > /* Update the free vmap_area. */ > ret = va_clip(root, head, va, nva_start_addr, size); > - if (WARN_ON_ONCE(ret)) > - return vend; > Not clear why you remove this WARN_ON by this patch. It should be a separate patch or just keep it as is. The warning here can mean that something is really wrong, especially if NOTHING_FIT. So we definitely want the warning. > + if (ret) > + return ret; > > return nva_start_addr; > } > > /* > * Returns a start address of the newly allocated area, if success. > - * Otherwise a vend is returned that indicates failure. > + * Otherwise an error value is returned that indicates failure. > */ > static __always_inline unsigned long > __alloc_vmap_area(struct rb_root *root, struct list_head *head, > @@ -1795,14 +1795,13 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head, > > va = find_vmap_lowest_match(root, size, align, vstart, adjust_search_size); > if (unlikely(!va)) > - return vend; > + return -ENOENT; > > nva_start_addr = va_alloc(va, root, head, size, align, vstart, vend); > - if (nva_start_addr == vend) > - return vend; > > #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK > - find_vmap_lowest_match_check(root, head, size, align); > + if (!IS_ERR_VALUE(nva_start_addr)) > Just keep it as it was. No need to check if addr is valid or not. > + find_vmap_lowest_match_check(root, head, size, align); > #endif > > return nva_start_addr; > @@ -1932,7 +1931,7 @@ node_alloc(unsigned long size, unsigned long align, > struct vmap_area *va; > > *vn_id = 0; > - *addr = vend; > + *addr = -EINVAL; > > /* > * Fallback to a global heap if not vmalloc or there > @@ -2012,20 +2011,20 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > } > > retry: > - if (addr == vend) { > + if (IS_ERR_VALUE(addr)) { > preload_this_cpu_lock(&free_vmap_area_lock, gfp_mask, node); > addr = __alloc_vmap_area(&free_vmap_area_root, &free_vmap_area_list, > size, align, vstart, vend); > spin_unlock(&free_vmap_area_lock); > } > > - trace_alloc_vmap_area(addr, size, align, vstart, vend, addr == vend); > + trace_alloc_vmap_area(addr, size, align, vstart, vend, IS_ERR_VALUE(addr)); > > /* > - * If an allocation fails, the "vend" address is > + * If an allocation fails, the error value is > * returned. Therefore trigger the overflow path. > */ > - if (unlikely(addr == vend)) > + if (IS_ERR_VALUE(addr)) > goto overflow; > > va->va_start = addr; > @@ -4753,9 +4752,10 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, > > ret = va_clip(&free_vmap_area_root, > &free_vmap_area_list, va, start, size); > - if (WARN_ON_ONCE(unlikely(ret))) > - /* It is a BUG(), but trigger recovery instead. */ Keep the comment. > + if ((unlikely(ret))) { > + WARN_ONCE(1, "%s error: errno (%d)\n", __func__, ret); > goto recovery; > + } > -- Uladzislau Rezki