[PATCH net-next v2 2/3] net: devmem: use memory provider helpers for net_iovs

[Stanislav Fomichev <sdf.kernel@gmail.com>]

Use public memory-provider helpers for DMA address storage and page-pool
association instead of open-coding page_pool state and accounting.

Zero the net_iov array because net_mp_niov_set_page_pool() ORs
PP_SIGNATURE into pp_magic. Reject DMA addresses that cannot be
represented in net_iov metadata.

Reviewed-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
 net/core/devmem.c | 31 +++++++++++--------------------
 1 file changed, 11 insertions(+), 20 deletions(-)

diff --git a/net/core/devmem.c b/net/core/devmem.c
index 704d02bd8bc8..71c83730d73d 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -17,11 +17,9 @@
 #include <net/page_pool/memory_provider.h>
 #include <net/sock.h>
 #include <net/tcp.h>
-#include <trace/events/page_pool.h>
 
 #include "devmem.h"
 #include "mp_dmabuf_devmem.h"
-#include "page_pool_priv.h"
 
 /* Device memory support */
 
@@ -273,7 +271,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, void *vdev,
 			goto err_unmap;
 		}
 	}
-	binding->area.niovs = kvmalloc_objs(*binding->area.niovs,
+	binding->area.niovs = kvzalloc_objs(*binding->area.niovs,
 					    binding->area.num_niovs);
 	if (!binding->area.niovs) {
 		err = -ENOMEM;
@@ -300,8 +298,12 @@ net_devmem_bind_dmabuf(struct net_device *dev, void *vdev,
 		for (i = 0; i < nr_niovs; i++, niov_idx++) {
 			niov = &binding->area.niovs[niov_idx];
 			net_iov_init(niov, &binding->area, NET_IOV_DMABUF);
-			page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov),
-						      dma_addr);
+			if (net_mp_niov_set_dma_addr(niov, dma_addr)) {
+				err = -EFAULT;
+				NL_SET_ERR_MSG(extack,
+					       "dmabuf DMA address cannot be represented");
+				goto err_free_niovs;
+			}
 			if (direction == DMA_TO_DEVICE)
 				binding->tx_vec[niov_idx] = niov;
 			else
@@ -467,19 +469,9 @@ netmem_ref mp_dmabuf_devmem_alloc_netmems(struct page_pool *pool, gfp_t gfp)
 	if (unlikely(!allocated))
 		return 0;
 
-	for (i = 0; i < allocated; i++) {
-		struct net_iov *niov = netmem_to_net_iov(netmems[i]);
-
-		niov->desc.pp_magic = 0;
-		niov->desc.pp = NULL;
-		atomic_long_set(&niov->desc.pp_ref_count, 0);
-
-		page_pool_set_pp_info(pool, netmems[i]);
-
-		pool->pages_state_hold_cnt++;
-		trace_page_pool_state_hold(pool, netmems[i],
-					   pool->pages_state_hold_cnt);
-	}
+	for (i = 0; i < allocated; i++)
+		net_mp_niov_set_page_pool(pool,
+					  netmem_to_net_iov(netmems[i]));
 
 	/* Return the last one, the rest stay in the page_pool cache. */
 	allocated--;
@@ -504,8 +496,7 @@ bool mp_dmabuf_devmem_release_page(struct page_pool *pool, netmem_ref netmem)
 	if (WARN_ON_ONCE(refcount != 1))
 		return false;
 
-	page_pool_clear_pp_info(netmem);
-
+	net_mp_niov_clear_page_pool(netmem_to_net_iov(netmem));
 	net_devmem_free_dmabuf(netmem_to_net_iov(netmem));
 
 	/* We don't want the page pool put_page()ing our net_iovs. */
-- 
2.53.0-Meta