[PATCH 2/5] mm/hugetlb: Remove prepare_hugepage_range()

Peter Xu
2025-06-13T13:41:26Z

Only mips and loongarch implemented this API, however what it does was
checking against stack overflow for either len or addr. That's already
done in arch's arch_get_unmapped_area*() functions, hence not needed.

It means the whole API is pretty much obsolete at least now, remove it
completely.

Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: loongarch@lists.linux.dev
Cc: linux-mips@vger.kernel.org
Signed-off-by: Peter Xu <peterx@redhat.com>
---
arch/loongarch/include/asm/hugetlb.h | 14 --------------
arch/mips/include/asm/hugetlb.h | 14 --------------
fs/hugetlbfs/inode.c | 8 ++------
include/asm-generic/hugetlb.h | 8 --------
include/linux/hugetlb.h | 6 ------
5 files changed, 2 insertions(+), 48 deletions(-)

diff --git a/arch/loongarch/include/asm/hugetlb.h b/arch/loongarch/include/asm/hugetlb.h
index 4dc4b3e04225..ab68b594f889 100644
--- a/arch/loongarch/include/asm/hugetlb.h
+++ b/arch/loongarch/include/asm/hugetlb.h
@@ -10,20 +10,6 @@

uint64_t pmd_to_entrylo(unsigned long pmd_val);

-#define __HAVE_ARCH_PREPARE_HUGEPAGE_RANGE
-static inline int prepare_hugepage_range(struct file *file,
- unsigned long addr,
- unsigned long len)
-{
- unsigned long task_size = STACK_TOP;
-
- if (len > task_size)
- return -ENOMEM;
- if (task_size - len < addr)
- return -EINVAL;
- return 0;
-}
-
#define __HAVE_ARCH_HUGE_PTE_CLEAR
static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long sz)
diff --git a/arch/mips/include/asm/hugetlb.h b/arch/mips/include/asm/hugetlb.h
index fbc71ddcf0f6..8c460ce01ffe 100644
--- a/arch/mips/include/asm/hugetlb.h
+++ b/arch/mips/include/asm/hugetlb.h
@@ -11,20 +11,6 @@

#include <asm/page.h>

-#define __HAVE_ARCH_PREPARE_HUGEPAGE_RANGE
-static inline int prepare_hugepage_range(struct file *file,
- unsigned long addr,
- unsigned long len)
-{
- unsigned long task_size = STACK_TOP;
-
- if (len > task_size)
- return -ENOMEM;
- if (task_size - len < addr)
- return -EINVAL;
- return 0;
-}
-
#define __HAVE_ARCH_HUGE_PTEP_GET_AND_CLEAR
static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep,
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index fc03dd541b4d..32dff13463d2 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -179,12 +179,8 @@ hugetlb_get_unmapped_area(struct file *file, unsigned long addr,

if (len & ~huge_page_mask(h))
return -EINVAL;
- if (flags & MAP_FIXED) {
- if (addr & ~huge_page_mask(h))
- return -EINVAL;
- if (prepare_hugepage_range(file, addr, len))
- return -EINVAL;
- }
+ if ((flags & MAP_FIXED) && (addr & ~huge_page_mask(h)))
+ return -EINVAL;
if (addr)
addr0 = ALIGN(addr, huge_page_size(h));

diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
index 3e0a8fe9b108..4bce4f07f44f 100644
--- a/include/asm-generic/hugetlb.h
+++ b/include/asm-generic/hugetlb.h
@@ -114,14 +114,6 @@ static inline int huge_pte_none_mostly(pte_t pte)
}
#endif

-#ifndef __HAVE_ARCH_PREPARE_HUGEPAGE_RANGE
-static inline int prepare_hugepage_range(struct file *file,
- unsigned long addr, unsigned long len)
-{
- return 0;
-}
-#endif
-
#ifndef __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 42f374e828a2..85acdfdbe9f0 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -359,12 +359,6 @@ static inline void hugetlb_show_meminfo_node(int nid)
{
}

-static inline int prepare_hugepage_range(struct file *file,
- unsigned long addr, unsigned long len)
-{
- return -EINVAL;
-}
-
static inline void hugetlb_vma_lock_read(struct vm_area_struct *vma)
{
}
--
2.49.0