[PATCH 5/6] alpha: align hugetlb mappings in arch_get_unmapped_area()

[Matt Turner]

hugetlb_get_unmapped_area() does not align the address itself; it
delegates to mm_get_unmapped_area_vmaflags(), and the huge page
alignment is applied by generic_get_unmapped_area() and
generic_get_unmapped_area_topdown() via info.align_mask.

Alpha defines HAVE_ARCH_UNMAPPED_AREA and supplies its own
arch_get_unmapped_area(), which never sets align_mask. An
mmap(MAP_HUGETLB) with no address hint would therefore return a merely
page-aligned address.

Pass the file down to arch_get_unmapped_area_1() and set align_mask for
hugetlbfs mappings, as x86, s390, sparc and loongarch already do. This
is a no-op until alpha gains hugetlb support.

Signed-off-by: Matt Turner <mattst88@xxxxxxxxx>
---
 arch/alpha/kernel/osf_sys.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
index 7b6543d2cca3..61d806176213 100644
--- a/arch/alpha/kernel/osf_sys.c
+++ b/arch/alpha/kernel/osf_sys.c
@@ -38,6 +38,7 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/uio.h>
+#include <linux/hugetlb.h>
 #include <linux/vfs.h>
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
@@ -1201,14 +1202,16 @@ SYSCALL_DEFINE1(old_adjtimex, struct timex32 __user *, txc_p)
 /* Get an address range which is currently unmapped. */
 
 static unsigned long
-arch_get_unmapped_area_1(unsigned long addr, unsigned long len,
-		         unsigned long limit)
+arch_get_unmapped_area_1(struct file *filp, unsigned long addr,
+			 unsigned long len, unsigned long limit)
 {
 	struct vm_unmapped_area_info info = {};
 
 	info.length = len;
 	info.low_limit = addr;
 	info.high_limit = limit;
+	if (filp && is_file_hugepages(filp))
+		info.align_mask = huge_page_mask_align(filp);
 	return vm_unmapped_area(&info);
 }
 
@@ -1236,19 +1239,20 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	   this feature should be incorporated into all ports?  */
 
 	if (addr) {
-		addr = arch_get_unmapped_area_1 (PAGE_ALIGN(addr), len, limit);
+		addr = arch_get_unmapped_area_1 (filp, PAGE_ALIGN(addr), len,
+						 limit);
 		if (addr != (unsigned long) -ENOMEM)
 			return addr;
 	}
 
 	/* Next, try allocating at TASK_UNMAPPED_BASE.  */
-	addr = arch_get_unmapped_area_1 (PAGE_ALIGN(TASK_UNMAPPED_BASE),
+	addr = arch_get_unmapped_area_1 (filp, PAGE_ALIGN(TASK_UNMAPPED_BASE),
 					 len, limit);
 	if (addr != (unsigned long) -ENOMEM)
 		return addr;
 
 	/* Finally, try allocating in low memory.  */
-	addr = arch_get_unmapped_area_1 (PAGE_SIZE, len, limit);
+	addr = arch_get_unmapped_area_1 (filp, PAGE_SIZE, len, limit);
 
 	return addr;
 }

-- 
2.54.0