powerpc/mm: factor out creating/removing linear mapping

We want to stop abusing memory hotplug infrastructure in memtrace code
to perform allocations and remove the linear mapping. Instead we will use
alloc_contig_pages() and remove the linear mapping manually.

Let's factor out creating/removing the linear mapping into
arch_create_linear_mapping() / arch_remove_linear_mapping() - so in the
future, we might be able to have whole arch_add_memory() /
arch_remove_memory() be implemented in common code.

Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201111145322.15793-4-david@redhat.com

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 01ec2a2..8a86d81 100644 (file)
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -120,34 +120,26 @@ static void flush_dcache_range_chunked(unsigned long start, unsigned long stop,
        }
 }
 
-int __ref arch_add_memory(int nid, u64 start, u64 size,
-                         struct mhp_params *params)
+int __ref arch_create_linear_mapping(int nid, u64 start, u64 size,
+                                    struct mhp_params *params)
 {
-       unsigned long start_pfn = start >> PAGE_SHIFT;
-       unsigned long nr_pages = size >> PAGE_SHIFT;
        int rc;
 
        start = (unsigned long)__va(start);
        rc = create_section_mapping(start, start + size, nid,
                                    params->pgprot);
        if (rc) {
-               pr_warn("Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n",
+               pr_warn("Unable to create linear mapping for 0x%llx..0x%llx: %d\n",
                        start, start + size, rc);
                return -EFAULT;
        }
-
-       return __add_pages(nid, start_pfn, nr_pages, params);
+       return 0;
 }
 
-void __ref arch_remove_memory(int nid, u64 start, u64 size,
-                            struct vmem_altmap *altmap)
+void __ref arch_remove_linear_mapping(u64 start, u64 size)
 {
-       unsigned long start_pfn = start >> PAGE_SHIFT;
-       unsigned long nr_pages = size >> PAGE_SHIFT;
        int ret;
 
-       __remove_pages(start_pfn, nr_pages, altmap);
-
        /* Remove htab bolted mappings for this section of memory */
        start = (unsigned long)__va(start);
        flush_dcache_range_chunked(start, start + size, FLUSH_CHUNK_SIZE);
@@ -160,6 +152,29 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
         */
        vm_unmap_aliases();
 }
+
+int __ref arch_add_memory(int nid, u64 start, u64 size,
+                         struct mhp_params *params)
+{
+       unsigned long start_pfn = start >> PAGE_SHIFT;
+       unsigned long nr_pages = size >> PAGE_SHIFT;
+       int rc;
+
+       rc = arch_create_linear_mapping(nid, start, size, params);
+       if (rc)
+               return rc;
+       return __add_pages(nid, start_pfn, nr_pages, params);
+}
+
+void __ref arch_remove_memory(int nid, u64 start, u64 size,
+                             struct vmem_altmap *altmap)
+{
+       unsigned long start_pfn = start >> PAGE_SHIFT;
+       unsigned long nr_pages = size >> PAGE_SHIFT;
+
+       __remove_pages(start_pfn, nr_pages, altmap);
+       arch_remove_linear_mapping(start, size);
+}
 #endif
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d65c6fd..00b9e9b 100644 (file)
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -375,6 +375,9 @@ extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
                                          unsigned long pnum);
 extern struct zone *zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
                unsigned long nr_pages);
+extern int arch_create_linear_mapping(int nid, u64 start, u64 size,
+                                     struct mhp_params *params);
+void arch_remove_linear_mapping(u64 start, u64 size);
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 #endif /* __LINUX_MEMORY_HOTPLUG_H */