diff mbox

be2net: Bugfix for packet drop with kernel param swiotlb=force

Message ID OF433C3BAF.359D84C5-ON48257C84.002D80B1-48257C84.002E4C8C@zte.com.cn
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Jiang Biao Feb. 19, 2014, 8:25 a.m. UTC 
From: Li Fengmao <li.fengmao@zte.com.cn>

There will be packet drop with kernel param "swiotlb = force" on
Emulex 10Gb NIC using be2net driver. The problem is caused by
receiving skb without calling pci_unmap_page() in get_rx_page_info().
rx_page_info->last_page_user is initialized to false in
be_post_rx_frags() when current frag are mapped in the first half of
the same page with another frag. But in that case with
"swiotlb = force" param, data can not be copied into the page of
rx_page_info without calling pci_unmap_page, so the data frag mapped
in the first half of the page will be dropped.

It can be solved by creating only a mapping relation between frag
and page, and deleting rx_page_info->last_page_user to ensure
calling pci_unmap_page when handling each receiving frag.

Steps to reproduce the bug:
1. Prepare a Emulex Corporation OneConnect 10Gb NIC.
2. Add the kernel param like "swiotlb = force" in /boot/grub/grub.conf .
3. Reboot the system. (e.g exec reboot command)
3. Activate the interface. (e.g ifconfig eth0 192.168.1.2 up)
4. There will be packet drop when ping 192.168.1.2 from another host.

Signed-off-by: Li Fengmao <li.fengmao@zte.com.cn>
Signed-off-by: Long Chun <long.chun@zte.com.cn>
Reviewed-by: Wang Liang <wang.liang82@zte.com.cn>
Reviewed-by: Cai Qu <cai.qu@zte.com.cn>
Reviewed-by: Jiang Biao <jiang.biao2@zte.com.cn>


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Comments

David Miller Feb. 19, 2014, 9:44 p.m. UTC | #1 
From: jiang.biao2@zte.com.cn
Date: Wed, 19 Feb 2014 16:25:40 +0800

> +        dma_unmap_page(&adapter->pdev->dev,
> +               dma_unmap_addr(rx_page_info, bus),
> +               rx_frag_size, DMA_FROM_DEVICE);

This is not indented properly.

Arguments on the second and subsequent lines of a function call must
start exactly at the first column after the openning parenthesis of the
function call on the first line.

You must use the appropriate number of TAB and SPACE characters
necessary to do so.

If you are indenting only using TAB characters, you are doing it wrong.
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diff mbox

Patch

--- old/drivers/net/ethernet/emulex/benet/be_main.c	2014-02-18 03:34:15.206388270 -0500
+++ new/drivers/net/ethernet/emulex/benet/be_main.c	2014-02-18 03:44:17.368388223 -0500
@@ -1018,13 +1018,9 @@  get_rx_page_info(struct be_adapter *adap
 	rx_page_info = &rxo->page_info_tbl[frag_idx];
 	BUG_ON(!rx_page_info->page);

-	if (rx_page_info->last_page_user) {
-		dma_unmap_page(&adapter->pdev->dev,
-			       dma_unmap_addr(rx_page_info, bus),
-			       adapter->big_page_size, DMA_FROM_DEVICE);
-		rx_page_info->last_page_user = false;
-	}
-
+        dma_unmap_page(&adapter->pdev->dev,
+               dma_unmap_addr(rx_page_info, bus),
+               rx_frag_size, DMA_FROM_DEVICE);
 	atomic_dec(&rxq->used);
 	return rx_page_info;
 }
@@ -1344,20 +1340,15 @@  static void be_post_rx_frags(struct be_r

 	page_info = &rxo->page_info_tbl[rxq->head];
 	for (posted = 0; posted < MAX_RX_POST && !page_info->page; posted++) {
-		if (!pagep) {
-			pagep = be_alloc_pages(adapter->big_page_size, gfp);
-			if (unlikely(!pagep)) {
-				rx_stats(rxo)->rx_post_fail++;
-				break;
-			}
-			page_dmaaddr = dma_map_page(&adapter->pdev->dev, pagep,
-						    0, adapter->big_page_size,
-						    DMA_FROM_DEVICE);
-			page_info->page_offset = 0;
-		} else {
-			get_page(pagep);
-			page_info->page_offset = page_offset + rx_frag_size;
+		pagep = be_alloc_pages(rx_frag_size, gfp);
+		if (unlikely(!pagep)) {
+			rx_stats(rxo)->rx_post_fail++;
+			break;
 		}
+		page_dmaaddr = dma_map_page(&adapter->pdev->dev, pagep,
+						    0, rx_frag_size,
+						    DMA_FROM_DEVICE);
+		page_info->page_offset = 0;
 		page_offset = page_info->page_offset;
 		page_info->page = pagep;
 		dma_unmap_addr_set(page_info, bus, page_dmaaddr);
@@ -1367,12 +1358,7 @@  static void be_post_rx_frags(struct be_r
 		rxd->fragpa_lo = cpu_to_le32(frag_dmaaddr & 0xFFFFFFFF);
 		rxd->fragpa_hi = cpu_to_le32(upper_32_bits(frag_dmaaddr));

-		/* Any space left in the current big page for another frag? */
-		if ((page_offset + rx_frag_size + rx_frag_size) >
-					adapter->big_page_size) {
-			pagep = NULL;
-			page_info->last_page_user = true;
-		}
+		pagep = NULL;

 		prev_page_info = page_info;
 		queue_head_inc(rxq);