From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC0592750EC for ; Tue, 15 Apr 2025 06:44:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744699487; cv=none; b=gAeqkZax7O1/Ww6wujyhVS0JlcfbmEVMA4Od34Y3+J6dmw1HtKLK0Zp2rvXqgnnISZO3xr0Qn4SPiadVQdtQRcjt07TOkddPZybGF98FTo+C7gX1xfE011yIwOJDpXbEG6M77iBwp6Djj7KKgN5llfSsR86pTaLdl5ujWN6Dvn8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744699487; c=relaxed/simple; bh=tPEz55PQ9rXlr2hf1Exf91Zz3e31R+9I5onFcqtQOA4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=K6EM6zpJV5OkJnxr52v0t0t0RMOalSsFz9NhIuKrV6+OzC8qWi8LaEk3k5l4AFj/Oq8k+o7Z0cUP92mevI0RGw0DNhSNLAXjy7XggyE9M8tp0NVsOAOyw2rfm4MAVnd7lj6qBsSzSNg6AM8tQCH+zAcWg8FlniBxhQRtC0WvcAg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=F0YP+kRX; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="F0YP+kRX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744699482; 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: in-reply-to:in-reply-to:references:references; bh=SutGNxLhkdu4G6mctAW9YWzgG+lju1obYh/lVOUIxqc=; b=F0YP+kRX128tp0u2j1YBkpVDxdJfYvpuo+bfRWkgmsbUo2o4Zn6Hyz7VQSU4LkcnPss4mZ 6beSfKg2tOeEhS0EZWys1KhR4Au1lXvD7ngMPy6iLIRE0gCRz7elcJVQpoYFiiBBnRqGow ndRRDkV6wZTqb0Is4zS8X2jDeu4xWUY= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-141-gw7uLWJdOj-6ft0pGCtvow-1; Tue, 15 Apr 2025 02:44:41 -0400 X-MC-Unique: gw7uLWJdOj-6ft0pGCtvow-1 X-Mimecast-MFC-AGG-ID: gw7uLWJdOj-6ft0pGCtvow_1744699479 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E113A1800361; Tue, 15 Apr 2025 06:44:38 +0000 (UTC) Received: from localhost (unknown [10.72.112.37]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 96BEC19560AD; Tue, 15 Apr 2025 06:44:37 +0000 (UTC) Date: Tue, 15 Apr 2025 14:44:33 +0800 From: Baoquan He To: linux-mm@kvack.org Cc: 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250415023952.27850-6-bhe@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 On 04/15/25 at 10:39am, 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 ^^^^^^^^^ Sorry, above line was added mistakenly in log draft, should be removed. > > 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; > + 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)) > + 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. */ > + if ((unlikely(ret))) { > + WARN_ONCE(1, "%s error: errno (%d)\n", __func__, ret); > goto recovery; > + } > > /* Allocated area. */ > va = vas[area]; > -- > 2.41.0 >