book3s64/hash: Add hash_debug_pagealloc_alloc_slots() function

This adds hash_debug_pagealloc_alloc_slots() function instead of open
coding that in htab_initialize(). This is required since we will be
separating the kfence functionality to not depend upon debug_pagealloc.

Now that everything required for debug_pagealloc is under a #ifdef
config. Bring in linear_map_hash_slots and linear_map_hash_count
variables under the same config too.

Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/d1d5aabe1e4c693a983e59ccf3de08e3c28c5161.1729271995.git.ritesh.list@gmail.com

arch/powerpc/mm/book3s64/hash_utils.c

@@ -123,8 +123,6 @@ EXPORT_SYMBOL_GPL(mmu_slb_size);
 #ifdef CONFIG_PPC_64K_PAGES
 int mmu_ci_restrictions;
 #endif
-static u8 *linear_map_hash_slots;
-static unsigned long linear_map_hash_count;
 struct mmu_hash_ops mmu_hash_ops __ro_after_init;
 EXPORT_SYMBOL(mmu_hash_ops);
 
@@ -274,6 +272,8 @@ void hash__tlbiel_all(unsigned int action)
 }
 
 #ifdef CONFIG_DEBUG_PAGEALLOC
+static u8 *linear_map_hash_slots;
+static unsigned long linear_map_hash_count;
 static DEFINE_RAW_SPINLOCK(linear_map_hash_lock);
 
 static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
@@ -328,6 +328,19 @@ static void kernel_unmap_linear_page(unsigned long vaddr, unsigned long lmi)
 				     mmu_kernel_ssize, 0);
 }
 
+static inline void hash_debug_pagealloc_alloc_slots(void)
+{
+	if (!debug_pagealloc_enabled())
+		return;
+	linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
+	linear_map_hash_slots = memblock_alloc_try_nid(
+			linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT,
+			ppc64_rma_size,	NUMA_NO_NODE);
+	if (!linear_map_hash_slots)
+		panic("%s: Failed to allocate %lu bytes max_addr=%pa\n",
+		      __func__, linear_map_hash_count, &ppc64_rma_size);
+}
+
 static inline void hash_debug_pagealloc_add_slot(phys_addr_t paddr, int slot)
 {
 	if (!debug_pagealloc_enabled())
@@ -361,6 +374,7 @@ int hash__kernel_map_pages(struct page *page, int numpages,
 {
 	return 0;
 }
+static inline void hash_debug_pagealloc_alloc_slots(void) {}
 static inline void hash_debug_pagealloc_add_slot(phys_addr_t paddr, int slot) {}
 #endif /* CONFIG_DEBUG_PAGEALLOC */
 
@@ -1223,16 +1237,7 @@ static void __init htab_initialize(void)
 
 	prot = pgprot_val(PAGE_KERNEL);
 
-	if (debug_pagealloc_enabled()) {
-		linear_map_hash_count = memblock_end_of_DRAM() >> PAGE_SHIFT;
-		linear_map_hash_slots = memblock_alloc_try_nid(
-				linear_map_hash_count, 1, MEMBLOCK_LOW_LIMIT,
-				ppc64_rma_size,	NUMA_NO_NODE);
-		if (!linear_map_hash_slots)
-			panic("%s: Failed to allocate %lu bytes max_addr=%pa\n",
-			      __func__, linear_map_hash_count, &ppc64_rma_size);
-	}
-
+	hash_debug_pagealloc_alloc_slots();
 	/* create bolted the linear mapping in the hash table */
 	for_each_mem_range(i, &base, &end) {
 		size = end - base;