[PATCH] net/af_xdp: fix umem map size for zero copy

[Frank Du <frank.du@intel.com>]

The current calculation assumes that the mbufs are contiguous. However,
this assumption is incorrect when the memory spans across a huge page.
Correct to directly read the size from the mempool memory chunks.

Signed-off-by: Frank Du <frank.du@intel.com>
---
 drivers/net/af_xdp/rte_eth_af_xdp.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 268a130c49..cb95d17d13 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -1039,7 +1039,7 @@ eth_link_update(struct rte_eth_dev *dev __rte_unused,
 }
 
 #if defined(XDP_UMEM_UNALIGNED_CHUNK_FLAG)
-static inline uintptr_t get_base_addr(struct rte_mempool *mp, uint64_t *align)
+static inline uintptr_t get_memhdr_info(struct rte_mempool *mp, uint64_t *align, size_t *len)
 {
 	struct rte_mempool_memhdr *memhdr;
 	uintptr_t memhdr_addr, aligned_addr;
@@ -1048,6 +1048,7 @@ static inline uintptr_t get_base_addr(struct rte_mempool *mp, uint64_t *align)
 	memhdr_addr = (uintptr_t)memhdr->addr;
 	aligned_addr = memhdr_addr & ~(getpagesize() - 1);
 	*align = memhdr_addr - aligned_addr;
+	*len = memhdr->len;
 
 	return aligned_addr;
 }
@@ -1125,6 +1126,7 @@ xsk_umem_info *xdp_umem_configure(struct pmd_internals *internals,
 	void *base_addr = NULL;
 	struct rte_mempool *mb_pool = rxq->mb_pool;
 	uint64_t umem_size, align = 0;
+	size_t len = 0;
 
 	if (internals->shared_umem) {
 		if (get_shared_umem(rxq, internals->if_name, &umem) < 0)
@@ -1156,10 +1158,8 @@ xsk_umem_info *xdp_umem_configure(struct pmd_internals *internals,
 		}
 
 		umem->mb_pool = mb_pool;
-		base_addr = (void *)get_base_addr(mb_pool, &align);
-		umem_size = (uint64_t)mb_pool->populated_size *
-				(uint64_t)usr_config.frame_size +
-				align;
+		base_addr = (void *)get_memhdr_info(mb_pool, &align, &len);
+		umem_size = (uint64_t)len + align;
 
 		ret = xsk_umem__create(&umem->umem, base_addr, umem_size,
 				&rxq->fq, &rxq->cq, &usr_config);
-- 
2.34.1