Subject: [PATCH] powerpc: fix pgtable pmd cache init

From: Nicholas Piggin <[email-masked]>
Date: Wed, 4 Jan 2017 01:55:17 +1000

Commit 9b081e10805cd ("powerpc: port 64 bits pgtable_cache to 32 bits")
mixed up PMD_INDEX_SIZE and PMD_CACHE_INDEX a couple of times. This
resulted in 64s/hash/4k configs to panic at boot with a false positive
error check.

Fix that and simplify error handling by moving the check to the caller.

Fixes: 9b081e10805cd ("powerpc: port 64 bits pgtable_cache to 32 bits")
Cc: Christophe Leroy <[email-masked]>
Cc: Aneesh Kumar K.V <[email-masked]>
Cc: Scott Wood <[email-masked]>
Cc: [email-masked]
Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/mm/hugetlbpage.c |  6 +-----
 arch/powerpc/mm/init-common.c | 11 +++--------
 2 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 289df38fb7e0..f21f6b907d99 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -810,12 +810,8 @@ static int __init hugetlbpage_init(void)
 		 * if we have pdshift and shift value same, we don't
 		 * use pgt cache for hugepd.
 		 */
-		if (pdshift > shift) {
+		if (pdshift > shift)
 			pgtable_cache_add(pdshift - shift, NULL);
-			if (!PGT_CACHE(pdshift - shift))
-				panic("hugetlbpage_init(): could not create "
-				      "pgtable cache for %d bit pagesize\n", shift);
-		}
 #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
 		else if (!hugepte_cache) {
 			/*
diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index a175cd82ae8c..1a3be5ae1d07 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -80,6 +80,8 @@ void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
 	new = kmem_cache_create(name, table_size, align, 0, ctor);
 	kfree(name);
 	pgtable_cache[shift - 1] = new;
+	if (!new)
+		panic("Could not allocate pgtable cache for order %d", shift);
 	pr_debug("Allocated pgtable cache for order %d\n", shift);
 }
 
@@ -88,7 +90,7 @@ void pgtable_cache_init(void)
 {
 	pgtable_cache_add(PGD_INDEX_SIZE, pgd_ctor);
 
-	if (PMD_INDEX_SIZE && !PGT_CACHE(PMD_INDEX_SIZE))
+	if (PMD_CACHE_INDEX && !PGT_CACHE(PMD_CACHE_INDEX))
 		pgtable_cache_add(PMD_CACHE_INDEX, pmd_ctor);
 	/*
 	 * In all current configs, when the PUD index exists it's the
@@ -97,11 +99,4 @@ void pgtable_cache_init(void)
 	 */
 	if (PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE))
 		pgtable_cache_add(PUD_INDEX_SIZE, pud_ctor);
-
-	if (!PGT_CACHE(PGD_INDEX_SIZE))
-		panic("Couldn't allocate pgd cache");
-	if (PMD_INDEX_SIZE && !PGT_CACHE(PMD_INDEX_SIZE))
-		panic("Couldn't allocate pmd pgtable caches");
-	if (PUD_INDEX_SIZE && !PGT_CACHE(PUD_INDEX_SIZE))
-		panic("Couldn't allocate pud pgtable caches");
 }
-- 
2.11.0