[PATCH v2 bpf] xsk: Fix offset calculation in unaligned mode

[e.kubanski]

Bring back previous offset calculation behaviour
in AF_XDP unaligned umem mode.

In unaligned mode, upper 16 bits should contain
data offset, lower 48 bits should contain
only specific chunk location without offset.

Remove pool->headroom duplication into 48bit address.

Signed-off-by: Eryk Kubanski <e.kubanski@xxxxxxxxxxxxxxxxxxx>
Fixes: bea14124bacb ("xsk: Get rid of xdp_buff_xsk::orig_addr")
---
 include/net/xsk_buff_pool.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index 7f0a75d6563d..b3699a848844 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -232,8 +232,8 @@ static inline u64 xp_get_handle(struct xdp_buff_xsk *xskb,
 		return orig_addr;
 
 	offset = xskb->xdp.data - xskb->xdp.data_hard_start;
-	orig_addr -= offset;
 	offset += pool->headroom;
+	orig_addr -= offset;
 	return orig_addr + (offset << XSK_UNALIGNED_BUF_OFFSET_SHIFT);
 }
 
-- 
2.34.1