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mm/memory_hotplug: make add_memory() take the device_hotplug_lock

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[ Upstream commit 8df1d0e4a265f25dc1e7e7624ccdbcb4a6630c89 ]

add_memory() currently does not take the device_hotplug_lock, however
is aleady called under the lock from
	arch/powerpc/platforms/pseries/hotplug-memory.c
	drivers/acpi/acpi_memhotplug.c
to synchronize against CPU hot-remove and similar.

In general, we should hold the device_hotplug_lock when adding memory to
synchronize against online/offline request (e.g.  from user space) - which
already resulted in lock inversions due to device_lock() and
mem_hotplug_lock - see 30467e0b3b ("mm, hotplug: fix concurrent memory
hot-add deadlock").  add_memory()/add_memory_resource() will create memory
block devices, so this really feels like the right thing to do.

Holding the device_hotplug_lock makes sure that a memory block device
can really only be accessed (e.g. via .online/.state) from user space,
once the memory has been fully added to the system.

The lock is not held yet in
	drivers/xen/balloon.c
	arch/powerpc/platforms/powernv/memtrace.c
	drivers/s390/char/sclp_cmd.c
	drivers/hv/hv_balloon.c
So, let's either use the locked variants or take the lock.

Don't export add_memory_resource(), as it once was exported to be used by
XEN, which is never built as a module.  If somebody requires it, we also
have to export a locked variant (as device_hotplug_lock is never
exported).

Link: http://lkml.kernel.org/r/20180925091457.28651-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
David Hildenbrand 2018-10-30 15:10:24 -07:00 committed by Greg Kroah-Hartman
parent 023c071f10
commit 02735d5987
6 changed files with 32 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/powerpc/platforms/pseries/hotplug-memory.c
View file

@ -676,7 +676,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
nid = memory_add_physaddr_to_nid(lmb->base_addr);
/* Add the memory */
rc = add_memory(nid, lmb->base_addr, block_sz);
rc = __add_memory(nid, lmb->base_addr, block_sz);
if (rc) {
invalidate_lmb_associativity_index(lmb);
return rc;

2
drivers/acpi/acpi_memhotplug.c
View file

@ -228,7 +228,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
if (node < 0)
node = memory_add_physaddr_to_nid(info->start_addr);
result = add_memory(node, info->start_addr, info->length);
result = __add_memory(node, info->start_addr, info->length);
/*
* If the memory block has been used by the kernel, add_memory()

7
drivers/base/memory.c
View file

@ -519,8 +519,12 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
return -EINVAL;
ret = lock_device_hotplug_sysfs();
if (ret)
goto out;
nid = memory_add_physaddr_to_nid(phys_addr);
ret = add_memory(nid, phys_addr,
ret = __add_memory(nid, phys_addr,
MIN_MEMORY_BLOCK_SIZE * sections_per_block);
if (ret)
@ -528,6 +532,7 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
ret = count;
out:
unlock_device_hotplug();
return ret;
}

3
drivers/xen/balloon.c
View file

@ -350,7 +350,10 @@ static enum bp_state reserve_additional_memory(void)
* callers drop the mutex before trying again.
*/
mutex_unlock(&balloon_mutex);
/* add_memory_resource() requires the device_hotplug lock */
lock_device_hotplug();
rc = add_memory_resource(nid, resource, memhp_auto_online);
unlock_device_hotplug();
mutex_lock(&balloon_mutex);
if (rc) {

1
include/linux/memory_hotplug.h
View file

@ -322,6 +322,7 @@ static inline void remove_memory(int nid, u64 start, u64 size) {}
extern void __ref free_area_init_core_hotplug(int nid);
extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
void *arg, int (*func)(struct memory_block *, void *));
extern int __add_memory(int nid, u64 start, u64 size);
extern int add_memory(int nid, u64 start, u64 size);
extern int add_memory_resource(int nid, struct resource *resource, bool online);
extern int arch_add_memory(int nid, u64 start, u64 size,

22
mm/memory_hotplug.c
View file

@ -1077,7 +1077,12 @@ static int online_memory_block(struct memory_block *mem, void *arg)
return device_online(&mem->dev);
}
/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
/*
* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
* and online/offline operations (triggered e.g. by sysfs).
*
* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
*/
int __ref add_memory_resource(int nid, struct resource *res, bool online)
{
u64 start, size;
@ -1146,9 +1151,9 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
mem_hotplug_done();
return ret;
}
EXPORT_SYMBOL_GPL(add_memory_resource);
int __ref add_memory(int nid, u64 start, u64 size)
/* requires device_hotplug_lock, see add_memory_resource() */
int __ref __add_memory(int nid, u64 start, u64 size)
{
struct resource *res;
int ret;
@ -1162,6 +1167,17 @@ int __ref add_memory(int nid, u64 start, u64 size)
release_memory_resource(res);
return ret;
}
int add_memory(int nid, u64 start, u64 size)
{
int rc;
lock_device_hotplug();
rc = __add_memory(nid, start, size);
unlock_device_hotplug();
return rc;
}
EXPORT_SYMBOL_GPL(add_memory);
#ifdef CONFIG_MEMORY_HOTREMOVE