+ sparc-mm-fix-max_order-usage-in-tsb_grow.patch added to mm-unstable branch

+ sparc-mm-fix-max_order-usage-in-tsb_grow.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: sparc/mm: fix MAX_ORDER usage in tsb_grow()
has been added to the -mm mm-unstable branch.  Its filename is
     sparc-mm-fix-max_order-usage-in-tsb_grow.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/sparc-mm-fix-max_order-usage-in-tsb_grow.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: sparc/mm: fix MAX_ORDER usage in tsb_grow()
Date: Wed, 15 Mar 2023 14:31:24 +0300

Patch series "Fix confusion around MAX_ORDER".

MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.

This definition is counter-intuitive and lead to number of bugs all over
the kernel.

Fix the bugs and then change the definition of MAX_ORDER to be
inclusive: the range of orders user can ask from buddy allocator is
0..MAX_ORDER now.


This patch (of 10):

MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.

Fix MAX_ORDER usage in tsb_grow().

Link: https://lkml.kernel.org/r/20230315113133.11326-1-kirill.shutemov@linux.intel.com
Link: https://lkml.kernel.org/r/20230315113133.11326-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Miller <davem@davemloft.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/sparc/mm/tsb.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/sparc/mm/tsb.c~sparc-mm-fix-max_order-usage-in-tsb_grow
+++ a/arch/sparc/mm/tsb.c
@@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsi
 	unsigned long new_rss_limit;
 	gfp_t gfp_flags;
 
-	if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
-		max_tsb_size = (PAGE_SIZE << MAX_ORDER);
+	if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
+		max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
 
 	new_cache_index = 0;
 	for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
_

Patches currently in -mm which might be from kirill.shutemov@linux.intel.com are

sparc-mm-fix-max_order-usage-in-tsb_grow.patch
um-fix-max_order-usage-in-linux_main.patch
floppy-fix-max_order-usage.patch
drm-i915-fix-max_order-usage-in-i915_gem_object_get_pages_internal.patch
genwqe-fix-max_order-usage.patch
perf-core-fix-max_order-usage-in-rb_alloc_aux_page.patch
mm-page_reporting-fix-max_order-usage-in-page_reporting_register.patch
mm-slub-fix-max_order-usage-in-calculate_order.patch
iommu-fix-max_order-usage-in-__iommu_dma_alloc_pages.patch
mm-treewide-redefine-max_order-sanely.patch