[PATCH v2 bpf-next] xdp: xdp_umem: fix umem pages mapping for 32bits systems

[Ivan Khoronzhuk]

Use kmap instead of page_address as it's not always in low memory.

Acked-by: Björn Töpel <bjorn.to...@intel.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronz...@linaro.org>
---

Based on bpf-next/master
v2..v1:
        included highmem.h

v1: https://lkml.org/lkml/2019/6/26/693

 net/xdp/xdp_umem.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 83de74ca729a..a0607969f8c0 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -14,6 +14,7 @@
 #include <linux/netdevice.h>
 #include <linux/rtnetlink.h>
 #include <linux/idr.h>
+#include <linux/highmem.h>
 
 #include "xdp_umem.h"
 #include "xsk_queue.h"
@@ -164,6 +165,14 @@ void xdp_umem_clear_dev(struct xdp_umem *umem)
        umem->zc = false;
 }
 
+static void xdp_umem_unmap_pages(struct xdp_umem *umem)
+{
+       unsigned int i;
+
+       for (i = 0; i < umem->npgs; i++)
+               kunmap(umem->pgs[i]);
+}
+
 static void xdp_umem_unpin_pages(struct xdp_umem *umem)
 {
        unsigned int i;
@@ -207,6 +216,7 @@ static void xdp_umem_release(struct xdp_umem *umem)
 
        xsk_reuseq_destroy(umem);
 
+       xdp_umem_unmap_pages(umem);
        xdp_umem_unpin_pages(umem);
 
        kfree(umem->pages);
@@ -369,7 +379,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct 
xdp_umem_reg *mr)
        }
 
        for (i = 0; i < umem->npgs; i++)
-               umem->pages[i].addr = page_address(umem->pgs[i]);
+               umem->pages[i].addr = kmap(umem->pgs[i]);
 
        return 0;
 
-- 
2.17.1