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authorDavidlohr Bueso <dave@stgolabs.net>2018-01-25 11:27:27 -0800
committerDoug Ledford <dledford@redhat.com>2018-01-26 10:43:46 -0500
commit487f6683f1b738e40aca2386b9f73da4ebb8223d (patch)
treea3d7ee5b94a0db12b991120ed446bf06d7b8adc3
parentdc728f779a71769526531d3d8593ab4ab1d8e436 (diff)
IB/mthca: Fix gup usage in mthca_map_user_db()
get_user_pages() must be called with mmap_sem held, currently it is not. In fact it is called under the user db_table->mutex. To fix this we can convert gup to use the fast alternative, and safely avoid taking mmap_sem, if possible. Furthermore this is safe wrt to the mutex as other callers that take the lock (unmap and alloc_db) are not called under mmap_sem (hence possible deadlock). Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Doug Ledford <dledford@redhat.com>
-rw-r--r--drivers/infiniband/hw/mthca/mthca_memfree.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
index 2a41ed74add8..2fe503e86c1d 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.c
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -472,7 +472,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
goto out;
}
- ret = get_user_pages(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages, NULL);
+ ret = get_user_pages_fast(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages);
if (ret < 0)
goto out;