mm/gup_benchmark: use proper FOLL_WRITE flags instead of hard-coding "1"

Fix the gup benchmark flags to use the symbolic FOLL_WRITE, instead of a
hard-coded "1" value.

Also, clean up the filtering of gup flags a little, by just doing it
once before issuing any of the get_user_pages*() calls.  This makes it
harder to overlook, instead of having little "gup_flags & 1" phrases in
the function calls.

Link: http://lkml.kernel.org/r/20200107224558.2362728-22-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
index ad9d5b1..8dba38e 100644 (file)
--- a/mm/gup_benchmark.c
+++ b/mm/gup_benchmark.c
@@ -49,18 +49,21 @@ static int __gup_benchmark_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 & 1,
+                       nr = get_user_pages_fast(addr, nr, gup->flags,
                                                 pages + i);
                        break;
                case GUP_LONGTERM_BENCHMARK:
                        nr = get_user_pages(addr, nr,
-                                           (gup->flags & 1) | FOLL_LONGTERM,
+                                           gup->flags | FOLL_LONGTERM,
                                            pages + i, NULL);
                        break;
                case GUP_BENCHMARK:
-                       nr = get_user_pages(addr, nr, gup->flags & 1, pages + i,
+                       nr = get_user_pages(addr, nr, gup->flags, pages + i,
                                            NULL);
                        break;
                default:

diff --git a/tools/testing/selftests/vm/gup_benchmark.c b/tools/testing/selftests/vm/gup_benchmark.c
index 485cf06..389327e 100644 (file)
--- a/tools/testing/selftests/vm/gup_benchmark.c
+++ b/tools/testing/selftests/vm/gup_benchmark.c
@@ -18,6 +18,9 @@
 #define GUP_LONGTERM_BENCHMARK _IOWR('g', 2, struct gup_benchmark)
 #define GUP_BENCHMARK          _IOWR('g', 3, struct gup_benchmark)
 
+/* Just the flags we need, copied from mm.h: */
+#define FOLL_WRITE     0x01    /* check pte is writable */
+
 struct gup_benchmark {
        __u64 get_delta_usec;
        __u64 put_delta_usec;
@@ -85,7 +88,8 @@ int main(int argc, char **argv)
        }
 
        gup.nr_pages_per_call = nr_pages;
-       gup.flags = write;
+       if (write)
+               gup.flags |= FOLL_WRITE;
 
        fd = open("/sys/kernel/debug/gup_benchmark", O_RDWR);
        if (fd == -1)