powerpc/powernv: hold device_hotplug_lock when calling memtrace_offline_pages()

davidhildenbrand · torvalds · commit 5666848774ef · 2018-10-31T08:54:17.000-07:00
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>
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
@@ -70,6 +70,7 @@ 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;
@@ -110,6 +111,7 @@ 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) {
 			/*
@@ -118,7 +120,6 @@ 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);
@@ -127,6 +128,7 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)
 			return base_pfn << PAGE_SHIFT;
 		}
 	}
+	unlock_device_hotplug();
 
 	return 0;
 }

Original file line number	Diff line number	Diff line change
`@@ -70,6 +70,7 @@ static int change_memblock_state(struct memory_block mem, void arg)`
`70`	`70`	`return 0;`
`71`	`71`	`}`
`72`	`72`
	`73`	`+/* called with device_hotplug_lock held */`
`73`	`74`	`static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)`
`74`	`75`	`{`
`75`	`76`	`u64 end_pfn = start_pfn + nr_pages - 1;`
`@@ -110,6 +111,7 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)`
`110`	`111`	`/* Trace memory needs to be aligned to the size */`
`111`	`112`	`end_pfn = round_down(end_pfn - nr_pages, nr_pages);`
`112`	`113`
	`114`	`+ lock_device_hotplug();`
`113`	`115`	`for (base_pfn = end_pfn; base_pfn > start_pfn; base_pfn -= nr_pages) {`
`114`	`116`	`if (memtrace_offline_pages(nid, base_pfn, nr_pages) == true) {`
`115`	`117`	`/*`
`@@ -118,7 +120,6 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)`
`118`	`120`	`* we never try to remove memory that spans two iomem`
`119`	`121`	`* resources.`
`120`	`122`	`*/`
`121`		`- lock_device_hotplug();`
`122`	`123`	`end_pfn = base_pfn + nr_pages;`
`123`	`124`	`for (pfn = base_pfn; pfn < end_pfn; pfn += bytes>> PAGE_SHIFT) {`
`124`	`125`	`__remove_memory(nid, pfn << PAGE_SHIFT, bytes);`
`@@ -127,6 +128,7 @@ static u64 memtrace_alloc_node(u32 nid, u64 size)`
`127`	`128`	`return base_pfn << PAGE_SHIFT;`
`128`	`129`	`}`
`129`	`130`	`}`
	`131`	`+ unlock_device_hotplug();`
`130`	`132`
`131`	`133`	`return 0;`
`132`	`134`	`}`