[PATCH net] net: mana: Switch to page pool for jumbo frames

[PATCH net] net: mana: Switch to page pool for jumbo frames

[Haiyang Zhang]

Since commit 8218f62c9c9b ("mm: page_frag: use initial zero offset for
page_frag_alloc_align()"), the netdev_alloc_frag() no longer works for
fragsz > PAGE_SIZE. And, this behavior is by design.

So, switch to page pool for jumbo frames instead of using page frag
allocators. This driver is using page pool for smaller MTUs already.

Cc: stable@vger.kernel.org
Fixes: 80f6215b450e ("net: mana: Add support for jumbo frame")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/net/ethernet/microsoft/mana/mana_en.c | 46 ++++---------------
 1 file changed, 9 insertions(+), 37 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 9a8171f099b6..4d41f4cca3d8 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -661,30 +661,16 @@ int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu, int num_qu
 	mpc->rxbpre_total = 0;
 
 	for (i = 0; i < num_rxb; i++) {
-		if (mpc->rxbpre_alloc_size > PAGE_SIZE) {
-			va = netdev_alloc_frag(mpc->rxbpre_alloc_size);
-			if (!va)
-				goto error;
-
-			page = virt_to_head_page(va);
-			/* Check if the frag falls back to single page */
-			if (compound_order(page) <
-			    get_order(mpc->rxbpre_alloc_size)) {
-				put_page(page);
-				goto error;
-			}
-		} else {
-			page = dev_alloc_page();
-			if (!page)
-				goto error;
+		page = dev_alloc_pages(get_order(mpc->rxbpre_alloc_size));
+		if (!page)
+			goto error;
 
-			va = page_to_virt(page);
-		}
+		va = page_to_virt(page);
 
 		da = dma_map_single(dev, va + mpc->rxbpre_headroom,
 				    mpc->rxbpre_datasize, DMA_FROM_DEVICE);
 		if (dma_mapping_error(dev, da)) {
-			put_page(virt_to_head_page(va));
+			put_page(page);
 			goto error;
 		}
 
@@ -1672,7 +1658,7 @@ static void mana_rx_skb(void *buf_va, bool from_pool,
 }
 
 static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,
-			     dma_addr_t *da, bool *from_pool, bool is_napi)
+			     dma_addr_t *da, bool *from_pool)
 {
 	struct page *page;
 	void *va;
@@ -1683,21 +1669,6 @@ static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,
 	if (rxq->xdp_save_va) {
 		va = rxq->xdp_save_va;
 		rxq->xdp_save_va = NULL;
-	} else if (rxq->alloc_size > PAGE_SIZE) {
-		if (is_napi)
-			va = napi_alloc_frag(rxq->alloc_size);
-		else
-			va = netdev_alloc_frag(rxq->alloc_size);
-
-		if (!va)
-			return NULL;
-
-		page = virt_to_head_page(va);
-		/* Check if the frag falls back to single page */
-		if (compound_order(page) < get_order(rxq->alloc_size)) {
-			put_page(page);
-			return NULL;
-		}
 	} else {
 		page = page_pool_dev_alloc_pages(rxq->page_pool);
 		if (!page)
@@ -1730,7 +1701,7 @@ static void mana_refill_rx_oob(struct device *dev, struct mana_rxq *rxq,
 	dma_addr_t da;
 	void *va;
 
-	va = mana_get_rxfrag(rxq, dev, &da, &from_pool, true);
+	va = mana_get_rxfrag(rxq, dev, &da, &from_pool);
 	if (!va)
 		return;
 
@@ -2172,7 +2143,7 @@ static int mana_fill_rx_oob(struct mana_recv_buf_oob *rx_oob, u32 mem_key,
 	if (mpc->rxbufs_pre)
 		va = mana_get_rxbuf_pre(rxq, &da);
 	else
-		va = mana_get_rxfrag(rxq, dev, &da, &from_pool, false);
+		va = mana_get_rxfrag(rxq, dev, &da, &from_pool);
 
 	if (!va)
 		return -ENOMEM;
@@ -2258,6 +2229,7 @@ static int mana_create_page_pool(struct mana_rxq *rxq, struct gdma_context *gc)
 	pprm.nid = gc->numa_node;
 	pprm.napi = &rxq->rx_cq.napi;
 	pprm.netdev = rxq->ndev;
+	pprm.order = get_order(rxq->alloc_size);
 
 	rxq->page_pool = page_pool_create(&pprm);
 
-- 
2.34.1

Re: [PATCH net] net: mana: Switch to page pool for jumbo frames

[Jakub Kicinski]

On Fri, 21 Mar 2025 18:04:35 -0700 Haiyang Zhang wrote:
> Since commit 8218f62c9c9b ("mm: page_frag: use initial zero offset for
> page_frag_alloc_align()"), the netdev_alloc_frag() no longer works for
> fragsz > PAGE_SIZE. And, this behavior is by design.

This is inaccurate, AFAIU. The user of frag allocator with fragsz >
PAGE_SIZE has _always_ been incorrect. It's just that it fails in
a more obvious way now? Please correct the commit message.
-- 
pw-bot: cr

RE: [EXTERNAL] Re: [PATCH net] net: mana: Switch to page pool for jumbo frames

[Haiyang Zhang]

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>
> Sent: Tuesday, March 25, 2025 12:14 PM
> To: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; Dexuan Cui
> <decui@microsoft.com>; stephen@networkplumber.org; KY Srinivasan
> <kys@microsoft.com>; Paul Rosswurm <paulros@microsoft.com>;
> olaf@aepfle.de; vkuznets <vkuznets@redhat.com>; davem@davemloft.net;
> wei.liu@kernel.org; edumazet@google.com; pabeni@redhat.com;
> leon@kernel.org; Long Li <longli@microsoft.com>;
> ssengar@linux.microsoft.com; linux-rdma@vger.kernel.org;
> daniel@iogearbox.net; john.fastabend@gmail.com; bpf@vger.kernel.org;
> ast@kernel.org; hawk@kernel.org; tglx@linutronix.de;
> shradhagupta@linux.microsoft.com; linux-kernel@vger.kernel.org;
> stable@vger.kernel.org
> Subject: [EXTERNAL] Re: [PATCH net] net: mana: Switch to page pool for
> jumbo frames
> 
> On Fri, 21 Mar 2025 18:04:35 -0700 Haiyang Zhang wrote:
> > Since commit 8218f62c9c9b ("mm: page_frag: use initial zero offset for
> > page_frag_alloc_align()"), the netdev_alloc_frag() no longer works for
> > fragsz > PAGE_SIZE. And, this behavior is by design.
> 
> This is inaccurate, AFAIU. The user of frag allocator with fragsz >
> PAGE_SIZE has _always_ been incorrect. It's just that it fails in
> a more obvious way now? Please correct the commit message.

Yes. I will correct the msg.