[PATCH] e1000: fix loss of multicast packets

[PATCH] e1000: fix loss of multicast packets

[Jeff Kirsher]

From: Jesse Brandeburg <jesse.brandeburg@intel.com>

e1000 (and e1000e, igb, ixgbe, ixgb) all do a series of
operations each time a multicast address is added.  The flow goes
something like

1) stack adds one multicast address
2) stack passes whole current list of unicast and multicast
   addresses to driver
3) driver clears entire list in hardware
4) driver programs each multicast address using iomem in a loop

This was causing multicast packets to be lost during the
reprogramming process.

reference with test program:
http://kerneltrap.org/mailarchive/linux-netdev/2009/3/14/5160514/thread

Thanks to Dave Boutcher for his report and test program.

This driver fix prepares an array all at once in memory and
programs it in one shot to the hardware, not requiring an "erase"
cycle.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Dave Boutcher <daveboutcher@gmail.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---

 drivers/net/e1000/e1000_main.c |   34 ++++++++++++++++++++++++++--------
 1 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 93b861d..a65023d 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -2335,6 +2335,12 @@ static void e1000_set_rx_mode(struct net_device *netdev)
 	int mta_reg_count = (hw->mac_type == e1000_ich8lan) ?
 				E1000_NUM_MTA_REGISTERS_ICH8LAN :
 				E1000_NUM_MTA_REGISTERS;
+	u32 *mcarray = kcalloc(mta_reg_count, sizeof(u32), GFP_ATOMIC);
+
+	if (!mcarray) {
+		DPRINTK(PROBE, ERR, "memory allocation failed\n");
+		return;
+	}
 
 	if (hw->mac_type == e1000_ich8lan)
 		rar_entries = E1000_RAR_ENTRIES_ICH8LAN;
@@ -2401,22 +2407,34 @@ static void e1000_set_rx_mode(struct net_device *netdev)
 	}
 	WARN_ON(uc_ptr != NULL);
 
-	/* clear the old settings from the multicast hash table */
-
-	for (i = 0; i < mta_reg_count; i++) {
-		E1000_WRITE_REG_ARRAY(hw, MTA, i, 0);
-		E1000_WRITE_FLUSH();
-	}
-
 	/* load any remaining addresses into the hash table */
 
 	for (; mc_ptr; mc_ptr = mc_ptr->next) {
+		u32 hash_reg, hash_bit, mta;
 		hash_value = e1000_hash_mc_addr(hw, mc_ptr->da_addr);
-		e1000_mta_set(hw, hash_value);
+		hash_reg = (hash_value >> 5) & 0x7F;
+		hash_bit = hash_value & 0x1F;
+		mta = (1 << hash_bit);
+		mcarray[hash_reg] |= mta;
 	}
 
+	/* write the hash table completely, write from bottom to avoid
+	 * both stupid write combining chipsets, and flushing each write */
+	for (i = mta_reg_count - 1; i >= 0 ; i--) {
+		/*
+		 * If we are on an 82544 has an errata where writing odd
+		 * offsets overwrites the previous even offset, but writing
+		 * backwards over the range solves the issue by always
+		 * writing the odd offset first
+		 */
+		E1000_WRITE_REG_ARRAY(hw, MTA, i, mcarray[i]);
+	}
+	E1000_WRITE_FLUSH();
+
 	if (hw->mac_type == e1000_82542_rev2_0)
 		e1000_leave_82542_rst(adapter);
+
+	kfree(mcarray);
 }
 
 /* Need to wait a few seconds after link up to get diagnostic information from

Re: [PATCH] e1000: fix loss of multicast packets

[David Miller]

From: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Date: Thu, 02 Apr 2009 19:00:32 -0700

> e1000 (and e1000e, igb, ixgbe, ixgb) all do a series of
> operations each time a multicast address is added.  The flow goes
> something like
> 
> 1) stack adds one multicast address
> 2) stack passes whole current list of unicast and multicast
>    addresses to driver
> 3) driver clears entire list in hardware
> 4) driver programs each multicast address using iomem in a loop
> 
> This was causing multicast packets to be lost during the
> reprogramming process.
> 
> reference with test program:
> http://kerneltrap.org/mailarchive/linux-netdev/2009/3/14/5160514/thread
> 
> Thanks to Dave Boutcher for his report and test program.
> 
> This driver fix prepares an array all at once in memory and
> programs it in one shot to the hardware, not requiring an "erase"
> cycle.
> 
> Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

Applied, thanks.

Re: [PATCH] e1000: fix loss of multicast packets

[Dave Boutcher]

On Fri, Mar 20, 2009 at 3:44 PM, Jesse Brandeburg
<jesse.brandeburg@intel.com> wrote:
> From: Jesse Brandeburg <jesse.brandeburg@intel.com>
> This driver fix prepares an array all at once in memory and programs it in
> one shot to the hardware, not requiring an "erase" cycle.
>
> Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> CC: Dave Boutcher <daveboutcher@gmail.com>

Jesse, I just with this patch in my e1000 environment and it works
great.  Almost 1,000,000 packets exchanged with active
membership join/drops going on and no packets lost.  Thanks
for the fast turnaround.

Thanks,
-- 
Dave B

Re: [PATCH] e1000: fix loss of multicast packets

[David Miller]

From: Dave Boutcher <daveboutcher@gmail.com>
Date: Sun, 22 Mar 2009 13:05:19 -0500

> On Fri, Mar 20, 2009 at 3:44 PM, Jesse Brandeburg
> <jesse.brandeburg@intel.com> wrote:
> > From: Jesse Brandeburg <jesse.brandeburg@intel.com>
> > This driver fix prepares an array all at once in memory and programs it in
> > one shot to the hardware, not requiring an "erase" cycle.
> >
> > Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> > CC: Dave Boutcher <daveboutcher@gmail.com>
> 
> Jesse, I just with this patch in my e1000 environment and it works
> great.  Almost 1,000,000 packets exchanged with active
> membership join/drops going on and no packets lost.  Thanks
> for the fast turnaround.

Thanks for testing Dave.

Intel folks, can we get this formally submitted soon?

Thanks.

Re: [PATCH] e1000: fix loss of multicast packets

[Jeff Kirsher]

On Mon, Mar 23, 2009 at 1:09 AM, David Miller <davem@davemloft.net> wrote:
> From: Dave Boutcher <daveboutcher@gmail.com>
> Date: Sun, 22 Mar 2009 13:05:19 -0500
>
>> On Fri, Mar 20, 2009 at 3:44 PM, Jesse Brandeburg
>> <jesse.brandeburg@intel.com> wrote:
>> > From: Jesse Brandeburg <jesse.brandeburg@intel.com>
>> > This driver fix prepares an array all at once in memory and programs it in
>> > one shot to the hardware, not requiring an "erase" cycle.
>> >
>> > Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
>> > CC: Dave Boutcher <daveboutcher@gmail.com>
>>
>> Jesse, I just with this patch in my e1000 environment and it works
>> great.  Almost 1,000,000 packets exchanged with active
>> membership join/drops going on and no packets lost.  Thanks
>> for the fast turnaround.
>
> Thanks for testing Dave.
>
> Intel folks, can we get this formally submitted soon?
>
> Thanks.
> --

Yes, I have it in my queue.  It should be in the next series of fixes
I will be sending out.

-- 
Cheers,
Jeff

Re: [PATCH] e1000: fix loss of multicast packets

[Dave Boutcher]

On Mon, Mar 23, 2009 at 9:53 PM, Jeff Kirsher
<jeffrey.t.kirsher@intel.com> wrote:
> On Mon, Mar 23, 2009 at 1:09 AM, David Miller <davem@davemloft.net> wrote:
>> From: Dave Boutcher <daveboutcher@gmail.com>
>> Date: Sun, 22 Mar 2009 13:05:19 -0500
>>
>>> On Fri, Mar 20, 2009 at 3:44 PM, Jesse Brandeburg
>>> <jesse.brandeburg@intel.com> wrote:
>>> > From: Jesse Brandeburg <jesse.brandeburg@intel.com>
>>> > This driver fix prepares an array all at once in memory and programs it in
>>> > one shot to the hardware, not requiring an "erase" cycle.
>>> >
>>> > Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
>>> > CC: Dave Boutcher <daveboutcher@gmail.com>
>>>
>>> Jesse, I just with this patch in my e1000 environment and it works
>>> great.  Almost 1,000,000 packets exchanged with active
>>> membership join/drops going on and no packets lost.  Thanks
>>> for the fast turnaround.
>>
>> Thanks for testing Dave.
>>
>> Intel folks, can we get this formally submitted soon?
>>
>> Thanks.
>> --
>
> Yes, I have it in my queue.  It should be in the next series of fixes
> I will be sending out.

At the risk of seeming demanding, an e1000e version as well?  That's
actually where the problem first showed up.

Thanks,

-- 
Dave B

Re: [PATCH] e1000: fix loss of multicast packets

[Jeff Kirsher]

On Tue, Mar 24, 2009 at 4:26 AM, Dave Boutcher <daveboutcher@gmail.com> wrote:
> On Mon, Mar 23, 2009 at 9:53 PM, Jeff Kirsher
> <jeffrey.t.kirsher@intel.com> wrote:
>> On Mon, Mar 23, 2009 at 1:09 AM, David Miller <davem@davemloft.net> wrote:
>>> From: Dave Boutcher <daveboutcher@gmail.com>
>>> Date: Sun, 22 Mar 2009 13:05:19 -0500
>>>
>>>> On Fri, Mar 20, 2009 at 3:44 PM, Jesse Brandeburg
>>>> <jesse.brandeburg@intel.com> wrote:
>>>> > From: Jesse Brandeburg <jesse.brandeburg@intel.com>
>>>> > This driver fix prepares an array all at once in memory and programs it in
>>>> > one shot to the hardware, not requiring an "erase" cycle.
>>>> >
>>>> > Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
>>>> > CC: Dave Boutcher <daveboutcher@gmail.com>
>>>>
>>>> Jesse, I just with this patch in my e1000 environment and it works
>>>> great.  Almost 1,000,000 packets exchanged with active
>>>> membership join/drops going on and no packets lost.  Thanks
>>>> for the fast turnaround.
>>>
>>> Thanks for testing Dave.
>>>
>>> Intel folks, can we get this formally submitted soon?
>>>
>>> Thanks.
>>> --
>>
>> Yes, I have it in my queue.  It should be in the next series of fixes
>> I will be sending out.
>
> At the risk of seeming demanding, an e1000e version as well?  That's
> actually where the problem first showed up.
>
> Thanks,
>
> --
> Dave B
> --

We also have a patch for e1000e as well. :)

-- 
Cheers,
Jeff