[PATCH 4.4 28/31] IB/core: Avoid unsigned int overflow in sg_alloc_table

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mark Bloch <redacted>

commit 3c7ba5760ab8eedec01159b267bb9bfcffe522ac upstream.

sg_alloc_table gets unsigned int as parameter while the driver
returns it as size_t. Check npages isn't greater than maximum
unsigned int.

Fixes: eeb8461e36c9 ("IB: Refactor umem to use linear SG table")
Signed-off-by: Mark Bloch <redacted>
Signed-off-by: Maor Gottlieb <redacted>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/core/umem.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c

@@ -175,7 +175,7 @@ struct ib_umem *ib_umem_get(struct ib_uc
 
 	cur_base = addr & PAGE_MASK;
 
-	if (npages == 0) {
+	if (npages == 0 || npages > UINT_MAX) {
 		ret = -EINVAL;
 		goto out;
 	}