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    Subject[PATCH v8 13/14] selftests/vm: gup_test: fix test flag
    Date
    In gup_test both gup_flags and test_flags use the same flags field.
    This is broken.

    Farther, in the actual gup_test.c all the passed gup_flags are erased and
    unconditionally replaced with FOLL_WRITE.

    Which means that test_flags are ignored, and code like this always
    performs pin dump test:

    155 if (gup->flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)
    156 nr = pin_user_pages(addr, nr, gup->flags,
    157 pages + i, NULL);
    158 else
    159 nr = get_user_pages(addr, nr, gup->flags,
    160 pages + i, NULL);
    161 break;

    Add a new test_flags field, to allow raw gup_flags to work.
    Add a new subcommand for DUMP_USER_PAGES_TEST to specify that pin test
    should be performed.
    Remove unconditional overwriting of gup_flags via FOLL_WRITE. But,
    preserve the previous behaviour where FOLL_WRITE was the default flag,
    and add a new option "-W" to unset FOLL_WRITE.

    Rename flags with gup_flags.

    With the fix, dump works like this:

    root@virtme:/# gup_test -c
    ---- page #0, starting from user virt addr: 0x7f8acb9e4000
    page:00000000d3d2ee27 refcount:2 mapcount:1 mapping:0000000000000000
    index:0x0 pfn:0x100bcf
    anon flags: 0x300000000080016(referenced|uptodate|lru|swapbacked)
    raw: 0300000000080016 ffffd0e204021608 ffffd0e208df2e88 ffff8ea04243ec61
    raw: 0000000000000000 0000000000000000 0000000200000000 0000000000000000
    page dumped because: gup_test: dump_pages() test
    DUMP_USER_PAGES_TEST: done

    root@virtme:/# gup_test -c -p
    ---- page #0, starting from user virt addr: 0x7fd19701b000
    page:00000000baed3c7d refcount:1025 mapcount:1 mapping:0000000000000000
    index:0x0 pfn:0x108008
    anon flags: 0x300000000080014(uptodate|lru|swapbacked)
    raw: 0300000000080014 ffffd0e204200188 ffffd0e205e09088 ffff8ea04243ee71
    raw: 0000000000000000 0000000000000000 0000040100000000 0000000000000000
    page dumped because: gup_test: dump_pages() test
    DUMP_USER_PAGES_TEST: done

    Refcount shows the difference between pin vs no-pin case.
    Also change type of nr from int to long, as it counts number of pages.

    Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
    Reviewed-by: John Hubbard <jhubbard@nvidia.com>
    ---
    mm/gup_test.c | 23 ++++++++++-------------
    mm/gup_test.h | 3 ++-
    tools/testing/selftests/vm/gup_test.c | 15 +++++++++++----
    3 files changed, 23 insertions(+), 18 deletions(-)

    diff --git a/mm/gup_test.c b/mm/gup_test.c
    index e3cf78e5873e..a6ed1c877679 100644
    --- a/mm/gup_test.c
    +++ b/mm/gup_test.c
    @@ -94,7 +94,7 @@ static int __gup_test_ioctl(unsigned int cmd,
    {
    ktime_t start_time, end_time;
    unsigned long i, nr_pages, addr, next;
    - int nr;
    + long nr;
    struct page **pages;
    int ret = 0;
    bool needs_mmap_lock =
    @@ -126,37 +126,34 @@ static int __gup_test_ioctl(unsigned int cmd,
    nr = (next - addr) / PAGE_SIZE;
    }

    - /* Filter out most gup flags: only allow a tiny subset here: */
    - gup->flags &= FOLL_WRITE;
    -
    switch (cmd) {
    case GUP_FAST_BENCHMARK:
    - nr = get_user_pages_fast(addr, nr, gup->flags,
    + nr = get_user_pages_fast(addr, nr, gup->gup_flags,
    pages + i);
    break;
    case GUP_BASIC_TEST:
    - nr = get_user_pages(addr, nr, gup->flags, pages + i,
    + nr = get_user_pages(addr, nr, gup->gup_flags, pages + i,
    NULL);
    break;
    case PIN_FAST_BENCHMARK:
    - nr = pin_user_pages_fast(addr, nr, gup->flags,
    + nr = pin_user_pages_fast(addr, nr, gup->gup_flags,
    pages + i);
    break;
    case PIN_BASIC_TEST:
    - nr = pin_user_pages(addr, nr, gup->flags, pages + i,
    + nr = pin_user_pages(addr, nr, gup->gup_flags, pages + i,
    NULL);
    break;
    case PIN_LONGTERM_BENCHMARK:
    nr = pin_user_pages(addr, nr,
    - gup->flags | FOLL_LONGTERM,
    + gup->gup_flags | FOLL_LONGTERM,
    pages + i, NULL);
    break;
    case DUMP_USER_PAGES_TEST:
    - if (gup->flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)
    - nr = pin_user_pages(addr, nr, gup->flags,
    + if (gup->test_flags & GUP_TEST_FLAG_DUMP_PAGES_USE_PIN)
    + nr = pin_user_pages(addr, nr, gup->gup_flags,
    pages + i, NULL);
    else
    - nr = get_user_pages(addr, nr, gup->flags,
    + nr = get_user_pages(addr, nr, gup->gup_flags,
    pages + i, NULL);
    break;
    default:
    @@ -187,7 +184,7 @@ static int __gup_test_ioctl(unsigned int cmd,

    start_time = ktime_get();

    - put_back_pages(cmd, pages, nr_pages, gup->flags);
    + put_back_pages(cmd, pages, nr_pages, gup->test_flags);

    end_time = ktime_get();
    gup->put_delta_usec = ktime_us_delta(end_time, start_time);
    diff --git a/mm/gup_test.h b/mm/gup_test.h
    index 90a6713d50eb..887ac1d5f5bc 100644
    --- a/mm/gup_test.h
    +++ b/mm/gup_test.h
    @@ -21,7 +21,8 @@ struct gup_test {
    __u64 addr;
    __u64 size;
    __u32 nr_pages_per_call;
    - __u32 flags;
    + __u32 gup_flags;
    + __u32 test_flags;
    /*
    * Each non-zero entry is the number of the page (1-based: first page is
    * page 1, so that zero entries mean "do nothing") from the .addr base.
    diff --git a/tools/testing/selftests/vm/gup_test.c b/tools/testing/selftests/vm/gup_test.c
    index 6c6336dd3b7f..943cc2608dc2 100644
    --- a/tools/testing/selftests/vm/gup_test.c
    +++ b/tools/testing/selftests/vm/gup_test.c
    @@ -37,13 +37,13 @@ int main(int argc, char **argv)
    {
    struct gup_test gup = { 0 };
    unsigned long size = 128 * MB;
    - int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 0;
    + int i, fd, filed, opt, nr_pages = 1, thp = -1, repeats = 1, write = 1;
    unsigned long cmd = GUP_FAST_BENCHMARK;
    int flags = MAP_PRIVATE;
    char *file = "/dev/zero";
    char *p;

    - while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwSH")) != -1) {
    + while ((opt = getopt(argc, argv, "m:r:n:F:f:abctTLUuwWSHp")) != -1) {
    switch (opt) {
    case 'a':
    cmd = PIN_FAST_BENCHMARK;
    @@ -65,9 +65,13 @@ int main(int argc, char **argv)
    */
    gup.which_pages[0] = 1;
    break;
    + case 'p':
    + /* works only with DUMP_USER_PAGES_TEST */
    + gup.test_flags |= GUP_TEST_FLAG_DUMP_PAGES_USE_PIN;
    + break;
    case 'F':
    /* strtol, so you can pass flags in hex form */
    - gup.flags = strtol(optarg, 0, 0);
    + gup.gup_flags = strtol(optarg, 0, 0);
    break;
    case 'm':
    size = atoi(optarg) * MB;
    @@ -93,6 +97,9 @@ int main(int argc, char **argv)
    case 'w':
    write = 1;
    break;
    + case 'W':
    + write = 0;
    + break;
    case 'f':
    file = optarg;
    break;
    @@ -140,7 +147,7 @@ int main(int argc, char **argv)

    gup.nr_pages_per_call = nr_pages;
    if (write)
    - gup.flags |= FOLL_WRITE;
    + gup.gup_flags |= FOLL_WRITE;

    fd = open("/sys/kernel/debug/gup_test", O_RDWR);
    if (fd == -1) {
    --
    2.25.1
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