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[209.132.183.28]) by mx.google.com with ESMTPS id o37si4358957qte.143.2019.05.07.11.38.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 May 2019 11:38:56 -0700 (PDT) Received-SPF: pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of david@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8C55C309B15B; Tue, 7 May 2019 18:38:55 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-95.ams2.redhat.com [10.36.116.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id 663664123; Tue, 7 May 2019 18:38:52 +0000 (UTC) From: David Hildenbrand To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, akpm@linux-foundation.org, Dan Williams , David Hildenbrand , Greg Kroah-Hartman , "Rafael J. Wysocki" , Alex Deucher , "David S. Miller" , Mark Brown , Chris Wilson , Oscar Salvador , Jonathan Cameron Subject: [PATCH v2 7/8] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail Date: Tue, 7 May 2019 20:38:03 +0200 Message-Id: <20190507183804.5512-8-david@redhat.com> In-Reply-To: <20190507183804.5512-1-david@redhat.com> References: <20190507183804.5512-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Tue, 07 May 2019 18:38:55 +0000 (UTC) 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: We really don't want anything during memory hotunplug to fail. We always pass a valid memory block device, that check can go. Avoid allocating memory and eventually failing. As we are always called under lock, we can use a static piece of memory. This avoids having to put the structure onto the stack, having to guess about the stack size of callers. Patch inspired by a patch from Oscar Salvador. In the future, there might be no need to iterate over nodes at all. mem->nid should tell us exactly what to remove. Memory block devices with mixed nodes (added during boot) should properly fenced off and never removed. Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Alex Deucher Cc: "David S. Miller" Cc: Mark Brown Cc: Chris Wilson Cc: David Hildenbrand Cc: Oscar Salvador Cc: Andrew Morton Cc: Jonathan Cameron Signed-off-by: David Hildenbrand --- drivers/base/node.c | 18 +++++------------- include/linux/node.h | 5 ++--- 2 files changed, 7 insertions(+), 16 deletions(-) diff --git a/drivers/base/node.c b/drivers/base/node.c index 04fdfa99b8bc..9be88fd05147 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -803,20 +803,14 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg) /* * Unregister memory block device under all nodes that it spans. + * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes). */ -int unregister_memory_block_under_nodes(struct memory_block *mem_blk) +void unregister_memory_block_under_nodes(struct memory_block *mem_blk) { - NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL); unsigned long pfn, sect_start_pfn, sect_end_pfn; + static nodemask_t unlinked_nodes; - if (!mem_blk) { - NODEMASK_FREE(unlinked_nodes); - return -EFAULT; - } - if (!unlinked_nodes) - return -ENOMEM; - nodes_clear(*unlinked_nodes); - + nodes_clear(unlinked_nodes); sect_start_pfn = section_nr_to_pfn(mem_blk->start_section_nr); sect_end_pfn = section_nr_to_pfn(mem_blk->end_section_nr); for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) { @@ -827,15 +821,13 @@ int unregister_memory_block_under_nodes(struct memory_block *mem_blk) continue; if (!node_online(nid)) continue; - if (node_test_and_set(nid, *unlinked_nodes)) + if (node_test_and_set(nid, unlinked_nodes)) continue; sysfs_remove_link(&node_devices[nid]->dev.kobj, kobject_name(&mem_blk->dev.kobj)); sysfs_remove_link(&mem_blk->dev.kobj, kobject_name(&node_devices[nid]->dev.kobj)); } - NODEMASK_FREE(unlinked_nodes); - return 0; } int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn) diff --git a/include/linux/node.h b/include/linux/node.h index 02a29e71b175..548c226966a2 100644 --- a/include/linux/node.h +++ b/include/linux/node.h @@ -139,7 +139,7 @@ extern int register_cpu_under_node(unsigned int cpu, unsigned int nid); extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid); extern int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg); -extern int unregister_memory_block_under_nodes(struct memory_block *mem_blk); +extern void unregister_memory_block_under_nodes(struct memory_block *mem_blk); extern int register_memory_node_under_compute_node(unsigned int mem_nid, unsigned int cpu_nid, @@ -175,9 +175,8 @@ static inline int register_mem_sect_under_node(struct memory_block *mem_blk, { return 0; } -static inline int unregister_memory_block_under_nodes(struct memory_block *mem_blk) +static inline void unregister_memory_block_under_nodes(struct memory_block *mem_blk) { - return 0; } static inline void register_hugetlbfs_with_node(node_registration_func_t reg, -- 2.20.1