From: John Hubbard <jhubbard@xxxxxxxxxx> Subject: 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@xxxxxxxxxx Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx> Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Reviewed-by: Christoph Hellwig <hch@xxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> Cc: Alex Williamson <alex.williamson@xxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Cc: Björn Töpel <bjorn.topel@xxxxxxxxx> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Hans Verkuil <hverkuil-cisco@xxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/infiniband/core/umem.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) --- a/drivers/infiniband/core/umem.c~ib-umem-use-get_user_pages_fast-to-pin-dma-pages +++ a/drivers/infiniband/core/umem.c @@ -257,16 +257,13 @@ struct ib_umem *ib_umem_get(struct ib_de 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_de 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); _
