On Wed, 1 Apr 2026 17:05:20 +0800 Li Wang <[email protected]> wrote:
> hugetlb_dio test uses sub-page offsets (pagesize / 2) to verify that
> hugepages used as DIO user buffers are correctly unpinned at completion.
>
> However, on filesystems with a logical block size larger than half the
> page size (e.g., 4K-sector block devices), these unaligned DIO writes
> are rejected with -EINVAL, causing the test to fail unexpectedly.
>
> Add get_dio_alignment() to query the filesystem's required DIO alignment
> via statx(STATX_DIOALIGN) and skip individual test cases whose file
> offset or write size is not a multiple of that alignment. Aligned cases
> continue to run so the core coverage is preserved.
>
> While here, open the temporary file once in main() and share the fd
> across all test cases instead of reopening it in each invocation.
>
> === Reproduce Steps ===
>
> # dd if=/dev/zero of=/tmp/test.img bs=1M count=512
> # losetup --sector-size 4096 /dev/loop0 /tmp/test.img
> # mkfs.xfs /dev/loop0
> # mkdir -p /mnt/dio_test
> # mount /dev/loop0 /mnt/dio_test
>
> // Modify test to open /mnt/dio_test and rebuild it:
> - fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
> + fd = open("/mnt/dio_test", O_TMPFILE | O_RDWR | O_DIRECT, 0664);
>
> # getconf PAGESIZE
> 4096
>
> # echo 100 >/proc/sys/vm/nr_hugepages
>
> # ./hugetlb_dio
> TAP version 13
> 1..4
> # No. Free pages before allocation : 100
> # No. Free pages after munmap : 100
> ok 1 free huge pages from 0-12288
> Bail out! Error writing to file
> : Invalid argument (22)
> # Planned tests != run tests (4 != 1)
> # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
Thanks, I update mm.git to this version,
> Notes:
> v5:
> - Perform that align checks at the beginning of run_dio_using_hugetlb()
> but not addinital run_test().
Here's how v5 altered mm.git:
---
a/tools/testing/selftests/mm/hugetlb_dio.c~selftests-mm-skip-hugetlb_dio-tests-when-dio-alignment-is-incompatible-v5
+++ a/tools/testing/selftests/mm/hugetlb_dio.c
@@ -66,7 +66,7 @@ static bool check_dio_alignment(unsigned
}
static void run_dio_using_hugetlb(int fd, unsigned int start_off,
- unsigned int end_off)
+ unsigned int end_off, unsigned int align)
{
char *buffer = NULL;
char *orig_buffer = NULL;
@@ -77,6 +77,9 @@ static void run_dio_using_hugetlb(int fd
const int mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB;
const int mmap_prot = PROT_READ | PROT_WRITE;
+ if (!check_dio_alignment(start_off, end_off, align))
+ return;
+
writesize = end_off - start_off;
/* Get the default huge page size */
@@ -130,15 +133,6 @@ static void run_dio_using_hugetlb(int fd
"free huge pages from %u-%u\n", start_off, end_off);
}
-static void run_test(int fd, unsigned int start_off,
- unsigned int end_off, unsigned int align)
-{
- if (!check_dio_alignment(start_off, end_off, align))
- return;
-
- run_dio_using_hugetlb(fd, start_off, end_off);
-}
-
int main(void)
{
int fd, align;
@@ -161,16 +155,16 @@ int main(void)
ksft_set_plan(4);
/* start and end is aligned to pagesize */
- run_test(fd, 0, (pagesize * 3), align);
+ run_dio_using_hugetlb(fd, 0, (pagesize * 3), align);
/* start is aligned but end is not aligned */
- run_test(fd, 0, (pagesize * 3) - (pagesize / 2), align);
+ run_dio_using_hugetlb(fd, 0, (pagesize * 3) - (pagesize / 2), align);
/* start is unaligned and end is aligned */
- run_test(fd, pagesize / 2, (pagesize * 3), align);
+ run_dio_using_hugetlb(fd, pagesize / 2, (pagesize * 3), align);
/* both start and end are unaligned */
- run_test(fd, pagesize / 2, (pagesize * 3) + (pagesize / 2), align);
+ run_dio_using_hugetlb(fd, pagesize / 2, (pagesize * 3) + (pagesize /
2), align);
close(fd);
_
