commit a31b264c2b415b29660da0bc2ba291a98629ce51 upstream.
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.
Link: http://lkml.kernel.org/r/20190527111152.16324-11-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Wei Yang richardw.yang@linux.intel.com Reviewed-by: Oscar Salvador osalvador@suse.de Acked-by: Michal Hocko mhocko@suse.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "Rafael J. Wysocki" rafael@kernel.org Cc: Alex Deucher alexander.deucher@amd.com Cc: "David S. Miller" davem@davemloft.net Cc: Mark Brown broonie@kernel.org Cc: Chris Wilson chris@chris-wilson.co.uk Cc: David Hildenbrand david@redhat.com Cc: Jonathan Cameron Jonathan.Cameron@huawei.com Cc: Andrew Banman andrew.banman@hpe.com Cc: Andy Lutomirski luto@kernel.org Cc: Anshuman Khandual anshuman.khandual@arm.com Cc: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Arun KS arunks@codeaurora.org Cc: Baoquan He bhe@redhat.com Cc: Benjamin Herrenschmidt benh@kernel.crashing.org Cc: Borislav Petkov bp@alien8.de Cc: Catalin Marinas catalin.marinas@arm.com Cc: Chintan Pandya cpandya@codeaurora.org Cc: Christophe Leroy christophe.leroy@c-s.fr Cc: Dan Williams dan.j.williams@intel.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Fenghua Yu fenghua.yu@intel.com Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@kernel.org Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Jun Yao yaojun8558363@gmail.com Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Logan Gunthorpe logang@deltatee.com Cc: Mark Rutland mark.rutland@arm.com Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: Mathieu Malaterre malat@debian.org Cc: Michael Ellerman mpe@ellerman.id.au Cc: Mike Rapoport rppt@linux.vnet.ibm.com Cc: "mike.travis@hpe.com" mike.travis@hpe.com Cc: Nicholas Piggin npiggin@gmail.com Cc: Paul Mackerras paulus@samba.org Cc: Pavel Tatashin pasha.tatashin@soleen.com Cc: Peter Zijlstra peterz@infradead.org Cc: Qian Cai cai@lca.pw Cc: Rich Felker dalias@libc.org Cc: Rob Herring robh@kernel.org Cc: Robin Murphy robin.murphy@arm.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Tony Luck tony.luck@intel.com Cc: Vasily Gorbik gor@linux.ibm.com Cc: Will Deacon will.deacon@arm.com Cc: Yoshinori Sato ysato@users.sourceforge.jp Cc: Yu Zhao yuzhao@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: David Hildenbrand david@redhat.com --- 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 1211794d658c..bdff237f4167 100644 --- a/drivers/base/node.c +++ b/drivers/base/node.c @@ -455,20 +455,14 @@ 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++) { @@ -479,15 +473,13 @@ 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 9a6db437f2d1..708939bae9aa 100644 --- a/include/linux/node.h +++ b/include/linux/node.h @@ -72,7 +72,7 @@ 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);
#ifdef CONFIG_HUGETLBFS extern void register_hugetlbfs_with_node(node_registration_func_t doregister, @@ -104,9 +104,8 @@ 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,