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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, anshuman.khandual@arm.com,
	christophe.leroy@csgroup.eu, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, npiggin@gmail.com,
	torvalds@linux-foundation.org
Subject: [patch 13/13] mm/ioremap: fix iomap_max_page_shift
Date: Fri, 14 May 2021 17:27:39 -0700	[thread overview]
Message-ID: <20210515002739.KFnavN0-K%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210514172634.9018621171d5334ceee97e95@linux-foundation.org>

From: Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: mm/ioremap: fix iomap_max_page_shift

iomap_max_page_shift is expected to contain a page shift, so it can't be a
'bool', has to be an 'unsigned int'

And fix the default values: P4D_SHIFT is when huge iomap is allowed.

However, on some architectures (eg: powerpc book3s/64), P4D_SHIFT is not a
constant so it can't be used to initialise a static variable.  So,
initialise iomap_max_page_shift with a maximum shift supported by the
architecture, it is gated by P4D_SHIFT in vmap_try_huge_p4d() anyway.

Link: https://lkml.kernel.org/r/ad2d366015794a9f21320dcbdd0a8eb98979e9df.1620898113.git.christophe.leroy@csgroup.eu
Fixes: bbc180a5adb0 ("mm: HUGE_VMAP arch support cleanup")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/ioremap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/mm/ioremap.c~mm-ioremap-fix-iomap_max_page_shift
+++ a/mm/ioremap.c
@@ -16,16 +16,16 @@
 #include "pgalloc-track.h"
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-static bool __ro_after_init iomap_max_page_shift = PAGE_SHIFT;
+static unsigned int __ro_after_init iomap_max_page_shift = BITS_PER_LONG - 1;
 
 static int __init set_nohugeiomap(char *str)
 {
-	iomap_max_page_shift = P4D_SHIFT;
+	iomap_max_page_shift = PAGE_SHIFT;
 	return 0;
 }
 early_param("nohugeiomap", set_nohugeiomap);
 #else /* CONFIG_HAVE_ARCH_HUGE_VMAP */
-static const bool iomap_max_page_shift = PAGE_SHIFT;
+static const unsigned int iomap_max_page_shift = PAGE_SHIFT;
 #endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
 
 int ioremap_page_range(unsigned long addr,
_


      parent reply	other threads:[~2021-05-15  0:27 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-15  0:26 incoming Andrew Morton
2021-05-15  0:27 ` [patch 01/13] mm/hugetlb: fix F_SEAL_FUTURE_WRITE Andrew Morton
2021-05-15  0:27 ` [patch 02/13] mm/hugetlb: fix cow where page writtable in child Andrew Morton
2021-05-15  0:27 ` [patch 03/13] mm, slub: move slub_debug static key enabling outside slab_mutex Andrew Morton
2021-05-15  0:27 ` [patch 04/13] kernel/resource: fix return code check in __request_free_mem_region Andrew Morton
2021-05-15  0:27 ` [patch 05/13] squashfs: fix divide error in calculate_skip() Andrew Morton
2021-05-15  0:27 ` [patch 06/13] userfaultfd: release page in error path to avoid BUG_ON Andrew Morton
2021-05-15  0:27 ` [patch 07/13] ksm: revert "use GET_KSM_PAGE_NOLOCK to get ksm page in remove_rmap_item_from_tree()" Andrew Morton
2021-05-15  0:27 ` [patch 08/13] mm: fix struct page layout on 32-bit systems Andrew Morton
2021-05-15  0:27 ` [patch 09/13] kasan: fix unit tests with CONFIG_UBSAN_LOCAL_BOUNDS enabled Andrew Morton
2021-05-15  0:27 ` [patch 10/13] mm/filemap: fix readahead return types Andrew Morton
2021-05-15  0:27 ` [patch 11/13] hfsplus: prevent corruption in shrinking truncate Andrew Morton
2021-05-15  0:27 ` [patch 12/13] docs: admin-guide: update description for kernel.modprobe sysctl Andrew Morton
2021-05-15  0:27 ` Andrew Morton [this message]

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