Subject: [PATCH 2/2] powerpc/mm/memtrace: Let the arch hotunplug code flush cache

From: Balbir Singh <[email-masked]>
Date: Fri, 6 Apr 2018 15:24:24 +1000

Don't do this via custom code, instead now that we have support
in the arch hotplug/hotunplug code, rely on those routines
to do the right thing.

Fixes: 9d5171a8f248 ("powerpc/powernv: Enable removal of memory for in memory tracing")
because the older code uses ppc64_caches.l1d.size instead of
ppc64_caches.l1d.line_size

Signed-off-by: Balbir Singh <[email-masked]>
---
 arch/powerpc/platforms/powernv/memtrace.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index de470caf0784..fc222a0c2ac4 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -82,19 +82,6 @@ static const struct file_operations memtrace_fops = {
 	.open	= simple_open,
 };
 
-static void flush_memory_region(u64 base, u64 size)
-{
-	unsigned long line_size = ppc64_caches.l1d.size;
-	u64 end = base + size;
-	u64 addr;
-
-	base = round_down(base, line_size);
-	end = round_up(end, line_size);
-
-	for (addr = base; addr < end; addr += line_size)
-		asm volatile("dcbf 0,%0" : "=r" (addr) :: "memory");
-}
-
 static int check_memblock_online(struct memory_block *mem, void *arg)
 {
 	if (mem->state != MEM_ONLINE)
@@ -132,10 +119,6 @@ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
 	walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE,
 			  change_memblock_state);
 
-	/* RCU grace period? */
-	flush_memory_region((u64)__va(start_pfn << PAGE_SHIFT),
-			    nr_pages << PAGE_SHIFT);
-
 	lock_device_hotplug();
 	remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
 	unlock_device_hotplug();
-- 
2.13.6