From: David Hildenbrand david@redhat.com
[ Upstream commit 5666848774ef43d3db5151ec518f1deb63515c20 ]
Let's perform all checking + offlining + removing under device_hotplug_lock, so nobody can mess with these devices via sysfs concurrently.
[david@redhat.com: take device_hotplug_lock outside of loop] Link: http://lkml.kernel.org/r/20180927092554.13567-6-david@redhat.com Link: http://lkml.kernel.org/r/20180925091457.28651-6-david@redhat.com Signed-off-by: David Hildenbrand david@redhat.com Reviewed-by: Pavel Tatashin pavel.tatashin@microsoft.com Reviewed-by: Rashmica Gupta rashmica.g@gmail.com Acked-by: Balbir Singh bsingharora@gmail.com Cc: Benjamin Herrenschmidt benh@kernel.crashing.org Cc: Paul Mackerras paulus@samba.org Cc: Michael Ellerman mpe@ellerman.id.au Cc: Rashmica Gupta rashmica.g@gmail.com Cc: Michael Neuling mikey@neuling.org Cc: Boris Ostrovsky boris.ostrovsky@oracle.com Cc: Dan Williams dan.j.williams@intel.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Haiyang Zhang haiyangz@microsoft.com Cc: Heiko Carstens heiko.carstens@de.ibm.com Cc: John Allen jallen@linux.vnet.ibm.com Cc: Jonathan Corbet corbet@lwn.net Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Juergen Gross jgross@suse.com Cc: Kate Stewart kstewart@linuxfoundation.org Cc: "K. Y. Srinivasan" kys@microsoft.com Cc: Len Brown lenb@kernel.org Cc: Martin Schwidefsky schwidefsky@de.ibm.com Cc: Mathieu Malaterre malat@debian.org Cc: Michal Hocko mhocko@suse.com Cc: Nathan Fontenot nfont@linux.vnet.ibm.com Cc: Oscar Salvador osalvador@suse.de Cc: Philippe Ombredanne pombredanne@nexb.com Cc: Rafael J. Wysocki rafael.j.wysocki@intel.com Cc: "Rafael J. Wysocki" rjw@rjwysocki.net Cc: Stephen Hemminger sthemmin@microsoft.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Vlastimil Babka vbabka@suse.cz Cc: YASUAKI ISHIMATSU yasu.isimatu@gmail.com 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 --- arch/powerpc/platforms/powernv/memtrace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c index c9a6d4f3403ce..cfbd242c3e011 100644 --- a/arch/powerpc/platforms/powernv/memtrace.c +++ b/arch/powerpc/platforms/powernv/memtrace.c @@ -99,6 +99,7 @@ static int change_memblock_state(struct memory_block *mem, void *arg) return 0; }
+/* called with device_hotplug_lock held */ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages) { u64 end_pfn = start_pfn + nr_pages - 1; @@ -139,6 +140,7 @@ static u64 memtrace_alloc_node(u32 nid, u64 size) /* Trace memory needs to be aligned to the size */ end_pfn = round_down(end_pfn - nr_pages, nr_pages);
+ lock_device_hotplug(); for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) { if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) { /* @@ -147,7 +149,6 @@ static u64 memtrace_alloc_node(u32 nid, u64 size) * we never try to remove memory that spans two iomem * resources. */ - lock_device_hotplug(); end_pfn = base_pfn + nr_pages; for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) { remove_memory(nid, pfn << PAGE_SHIFT, bytes); @@ -156,6 +157,7 @@ static u64 memtrace_alloc_node(u32 nid, u64 size) return base_pfn << PAGE_SHIFT; } } + unlock_device_hotplug();
return 0; }