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From: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
To: davem@davemloft.net
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Subject: [net-next 2/4] e1000: remove workaround for Errata 23 from jumbo alloc
Date: Thu, 17 May 2012 05:31:50 -0700	[thread overview]
Message-ID: <1337257912-8487-3-git-send-email-jeffrey.t.kirsher@intel.com> (raw)
In-Reply-To: <1337257912-8487-1-git-send-email-jeffrey.t.kirsher@intel.com>

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

According to the comment, errata 23 says that the memory we allocate
can't cross a 64KiB boundary. In case of jumbo frames we allocate
complete pages which can never cross the 64KiB boundary because
PAGE_SIZE should be a multiple of 64KiB so we stop either before the
boundary or start after it but never cross it. Furthermore the check
seems bogus because it looks at skb->data which is not seen by the HW
at all because we only pass the DMA address of the page we allocated. So
I *think* the workaround is not required here.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/e1000/e1000_main.c |   24 ------------------------
 1 files changed, 0 insertions(+), 24 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index f1aef68..fefbf4d 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -4391,30 +4391,6 @@ e1000_alloc_jumbo_rx_buffers(struct e1000_adapter *adapter,
 			break;
 		}
 
-		/* Fix for errata 23, can't cross 64kB boundary */
-		if (!e1000_check_64k_bound(adapter, skb->data, bufsz)) {
-			struct sk_buff *oldskb = skb;
-			e_err(rx_err, "skb align check failed: %u bytes at "
-			      "%p\n", bufsz, skb->data);
-			/* Try again, without freeing the previous */
-			skb = netdev_alloc_skb_ip_align(netdev, bufsz);
-			/* Failed allocation, critical failure */
-			if (!skb) {
-				dev_kfree_skb(oldskb);
-				adapter->alloc_rx_buff_failed++;
-				break;
-			}
-
-			if (!e1000_check_64k_bound(adapter, skb->data, bufsz)) {
-				/* give up */
-				dev_kfree_skb(skb);
-				dev_kfree_skb(oldskb);
-				break; /* while (cleaned_count--) */
-			}
-
-			/* Use new allocation */
-			dev_kfree_skb(oldskb);
-		}
 		buffer_info->skb = skb;
 		buffer_info->length = adapter->rx_buffer_len;
 check_page:
-- 
1.7.7.6

  parent reply	other threads:[~2012-05-17 12:31 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-17 12:31 [net-next v2 0/4][pull request] Intel Wired LAN Driver Updates Jeff Kirsher
2012-05-17 12:31 ` [net-next 1/4] e1000e: fix typo in definition of E1000_CTRL_EXT_FORCE_SMBUS Jeff Kirsher
2012-05-17 12:31 ` Jeff Kirsher [this message]
2012-05-17 12:31 ` [net-next v2 3/4] e1000: look in the page and not in skb->data for the last byte Jeff Kirsher
2012-05-17 12:31 ` [net-next 4/4] igb: Disable the BMC-to-OS Watchdog Enable bit for DMAC Jeff Kirsher
  -- strict thread matches above, loose matches on Subject: below --
2012-05-17 11:27 [net-next 0/4][pull request] Intel Wired LAN Driver Updates Jeff Kirsher
2012-05-17 11:27 ` [net-next 2/4] e1000: remove workaround for Errata 23 from jumbo alloc Jeff Kirsher
2012-05-17 14:40   ` Ben Hutchings
2012-05-17 19:32     ` David Miller

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