IB/umem: use get_user_pages_fast() to pin DMA pages

And get rid of the mmap_sem calls, as part of that.  Note that
get_user_pages_fast() will, if necessary, fall back to
__gup_longterm_unlocked(), which takes the mmap_sem as needed.

Link: http://lkml.kernel.org/r/20200107224558.2362728-10-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.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: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
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: 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/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 146f98fbf22b053f56530c83df04d8b77d890f09..f995b50ee1ccd8ee122adeaacc89e0077080dcbb 100644 (file)
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -257,16 +257,13 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
        sg = umem->sg_head.sgl;
 
        while (npages) {
-               down_read(&mm->mmap_sem);
-               ret = get_user_pages(cur_base,
-                                    min_t(unsigned long, npages,
-                                          PAGE_SIZE / sizeof (struct page *)),
-                                    gup_flags | FOLL_LONGTERM,
-                                    page_list, NULL);
-               if (ret < 0) {
-                       up_read(&mm->mmap_sem);
+               ret = get_user_pages_fast(cur_base,
+                                         min_t(unsigned long, npages,
+                                               PAGE_SIZE /
+                                               sizeof(struct page *)),
+                                         gup_flags | FOLL_LONGTERM, page_list);
+               if (ret < 0)
                        goto umem_release;
-               }
 
                cur_base += ret * PAGE_SIZE;
                npages   -= ret;
@@ -274,8 +271,6 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
                sg = ib_umem_add_sg_table(sg, page_list, ret,
                        dma_get_max_seg_size(device->dma_device),
                        &umem->sg_nents);
-
-               up_read(&mm->mmap_sem);
        }
 
        sg_mark_end(sg);