diff mbox series

[net] net: lan966x: Fix unmapping of received frames using FDMA

Message ID 20221031133421.1283196-1-horatiu.vultur@microchip.com (mailing list archive)
State Accepted
Commit fc57062f98b0b0ae52bc584d8fd5ac77c50df607
Delegated to: Netdev Maintainers
Headers show
Series [net] net: lan966x: Fix unmapping of received frames using FDMA | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 40 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Horatiu Vultur Oct. 31, 2022, 1:34 p.m. UTC 
When lan966x was receiving a frame, then it was building the skb and
after that it was calling dma_unmap_single with frame size as the
length. This actually has 2 issues:
1. It is using a length to map and a different length to unmap.
2. When the unmap was happening, the data was sync for cpu but it could
   be that this will overwrite what build_skb was initializing.

The fix for these two problems is to change the order of operations.
First to sync the frame for cpu, then to build the skb and in the end to
unmap using the correct size but without sync the frame again for cpu.

Fixes: c8349639324a ("net: lan966x: Add FDMA functionality")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
 .../ethernet/microchip/lan966x/lan966x_fdma.c  | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Nov. 2, 2022, 4:30 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 31 Oct 2022 14:34:21 +0100 you wrote:
> When lan966x was receiving a frame, then it was building the skb and
> after that it was calling dma_unmap_single with frame size as the
> length. This actually has 2 issues:
> 1. It is using a length to map and a different length to unmap.
> 2. When the unmap was happening, the data was sync for cpu but it could
>    be that this will overwrite what build_skb was initializing.
> 
> [...]

Here is the summary with links:
  - [net] net: lan966x: Fix unmapping of received frames using FDMA
    https://git.kernel.org/netdev/net/c/fc57062f98b0

You are awesome, thank you!
diff mbox series

Patch

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
index c235edd2b182a..e6948939ccc2b 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c
@@ -414,13 +414,15 @@  static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx)
 	/* Get the received frame and unmap it */
 	db = &rx->dcbs[rx->dcb_index].db[rx->db_index];
 	page = rx->page[rx->dcb_index][rx->db_index];
+
+	dma_sync_single_for_cpu(lan966x->dev, (dma_addr_t)db->dataptr,
+				FDMA_DCB_STATUS_BLOCKL(db->status),
+				DMA_FROM_DEVICE);
+
 	skb = build_skb(page_address(page), PAGE_SIZE << rx->page_order);
 	if (unlikely(!skb))
 		goto unmap_page;
 
-	dma_unmap_single(lan966x->dev, (dma_addr_t)db->dataptr,
-			 FDMA_DCB_STATUS_BLOCKL(db->status),
-			 DMA_FROM_DEVICE);
 	skb_put(skb, FDMA_DCB_STATUS_BLOCKL(db->status));
 
 	lan966x_ifh_get_src_port(skb->data, &src_port);
@@ -429,6 +431,10 @@  static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx)
 	if (WARN_ON(src_port >= lan966x->num_phys_ports))
 		goto free_skb;
 
+	dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr,
+			       PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE,
+			       DMA_ATTR_SKIP_CPU_SYNC);
+
 	skb->dev = lan966x->ports[src_port]->dev;
 	skb_pull(skb, IFH_LEN * sizeof(u32));
 
@@ -454,9 +460,9 @@  static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx)
 free_skb:
 	kfree_skb(skb);
 unmap_page:
-	dma_unmap_page(lan966x->dev, (dma_addr_t)db->dataptr,
-		       FDMA_DCB_STATUS_BLOCKL(db->status),
-		       DMA_FROM_DEVICE);
+	dma_unmap_single_attrs(lan966x->dev, (dma_addr_t)db->dataptr,
+			       PAGE_SIZE << rx->page_order, DMA_FROM_DEVICE,
+			       DMA_ATTR_SKIP_CPU_SYNC);
 	__free_pages(page, rx->page_order);
 
 	return NULL;