From: John Hubbard <jhubb...@nvidia.com>

1. Bug fix: the error handling release pages starting
at the first page that experienced an error.

2. Refinement: release_pages() is better than put_page()
in a loop.

3. Dead code removal: the check for (user_virt & ~page_mask)
is checking for a condition that can never happen,
because earlier:

    user_virt = user_virt & page_mask;

...so, remove that entire phrase.

4. Minor: As long as I'm here, shorten up a couple of long lines
in the same function, without harming the ability to
grep for the printed error message.

Cc: Ira Weiny <ira.we...@intel.com>
Cc: Jason Gunthorpe <j...@ziepe.ca>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Doug Ledford <dledf...@redhat.com>
Cc: linux-r...@vger.kernel.org
Cc: linux...@kvack.org
Signed-off-by: John Hubbard <jhubb...@nvidia.com>
---

v2: Fixes a kbuild test robot reported build failure, by directly
    including pagemap.h

 drivers/infiniband/core/umem_odp.c | 25 ++++++++++---------------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/drivers/infiniband/core/umem_odp.c 
b/drivers/infiniband/core/umem_odp.c
index acb882f279cb..83872c1f3f2c 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -40,6 +40,7 @@
 #include <linux/vmalloc.h>
 #include <linux/hugetlb.h>
 #include <linux/interval_tree_generic.h>
+#include <linux/pagemap.h>
 
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_umem.h>
@@ -648,25 +649,17 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp 
*umem_odp, u64 user_virt,
 
                if (npages < 0) {
                        if (npages != -EAGAIN)
-                               pr_warn("fail to get %zu user pages with error 
%d\n", gup_num_pages, npages);
+                               pr_warn("fail to get %zu user pages with error 
%d\n",
+                                       gup_num_pages, npages);
                        else
-                               pr_debug("fail to get %zu user pages with error 
%d\n", gup_num_pages, npages);
+                               pr_debug("fail to get %zu user pages with error 
%d\n",
+                                        gup_num_pages, npages);
                        break;
                }
 
                bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);
                mutex_lock(&umem_odp->umem_mutex);
                for (j = 0; j < npages; j++, user_virt += PAGE_SIZE) {
-                       if (user_virt & ~page_mask) {
-                               p += PAGE_SIZE;
-                               if (page_to_phys(local_page_list[j]) != p) {
-                                       ret = -EFAULT;
-                                       break;
-                               }
-                               put_page(local_page_list[j]);
-                               continue;
-                       }
-
                        ret = ib_umem_odp_map_dma_single_page(
                                        umem_odp, k, local_page_list[j],
                                        access_mask, current_seq);
@@ -684,9 +677,11 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp 
*umem_odp, u64 user_virt,
                mutex_unlock(&umem_odp->umem_mutex);
 
                if (ret < 0) {
-                       /* Release left over pages when handling errors. */
-                       for (++j; j < npages; ++j)
-                               put_page(local_page_list[j]);
+                       /*
+                        * Release pages, starting at the the first page
+                        * that experienced an error.
+                        */
+                       release_pages(&local_page_list[j], npages - j);
                        break;
                }
        }
-- 
2.21.0

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