powerpc/powernv/memtrace: Let the arch hotunplug code flush cache

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.

The existing flush doesn't work because it uses ppc64_caches.l1d.size
instead of ppc64_caches.l1d.line_size.

Fixes: 9d5171a8f248 ("powerpc/powernv: Enable removal of memory for in memory tracing")
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index de470caf07848e28864cbb8ff0129e4ed7aaf021..fc222a0c2ac46b06095ed831827d40e84994e3ca 100644 (file)
--- 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();