powerpc/mm: Limit resize_hpt_for_hotplug() call to hash guests only

During memory hotplug and unplug, resize_hpt_for_hotplug() gets called
for both hash and radix guests but it should be called only for hash
guests. Though the call does nothing in the radix guest case, it is
cleaner to push this call into hash specific memory hotplug routines.
Reported-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200727095704.1432916-1-bharata@linux.ibm.com

arch/powerpc/include/asm/sparsemem.h

@@ -17,12 +17,6 @@ extern int create_section_mapping(unsigned long start, unsigned long end,
 				  int nid, pgprot_t prot);
 extern int remove_section_mapping(unsigned long start, unsigned long end);
 
-#ifdef CONFIG_PPC_BOOK3S_64
-extern int resize_hpt_for_hotplug(unsigned long new_mem_size);
-#else
-static inline int resize_hpt_for_hotplug(unsigned long new_mem_size) { return 0; }
-#endif
-
 #ifdef CONFIG_NUMA
 extern int hot_add_scn_to_nid(unsigned long scn_addr);
 #else

arch/powerpc/mm/book3s64/hash_utils.c

@@ -785,7 +785,7 @@ static unsigned long __init htab_get_table_size(void)
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
-int resize_hpt_for_hotplug(unsigned long new_mem_size)
+static int resize_hpt_for_hotplug(unsigned long new_mem_size)
 {
 	unsigned target_hpt_shift;
 
@@ -819,6 +819,8 @@ int hash__create_section_mapping(unsigned long start, unsigned long end,
 		return -1;
 	}
 
+	resize_hpt_for_hotplug(memblock_phys_mem_size());
+
 	rc = htab_bolt_mapping(start, end, __pa(start),
 			       pgprot_val(prot), mmu_linear_psize,
 			       mmu_kernel_ssize);
@@ -836,6 +838,10 @@ int hash__remove_section_mapping(unsigned long start, unsigned long end)
 	int rc = htab_remove_mapping(start, end, mmu_linear_psize,
 				     mmu_kernel_ssize);
 	WARN_ON(rc < 0);
+
+	if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC)
+		pr_warn("Hash collision while resizing HPT\n");
+
 	return rc;
 }
 #endif /* CONFIG_MEMORY_HOTPLUG */

arch/powerpc/mm/mem.c

@@ -127,8 +127,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
 	unsigned long nr_pages = size >> PAGE_SHIFT;
 	int rc;
 
-	resize_hpt_for_hotplug(memblock_phys_mem_size());
-
 	start = (unsigned long)__va(start);
 	rc = create_section_mapping(start, start + size, nid,
 				    params->pgprot);
@@ -161,9 +159,6 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
 	 * hit that section of memory
 	 */
 	vm_unmap_aliases();
-
-	if (resize_hpt_for_hotplug(memblock_phys_mem_size()) == -ENOSPC)
-		pr_warn("Hash collision while resizing HPT\n");
 }
 #endif