| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <461AA339.3040503@redhat.com>
Date: Mon, 09 Apr 2007 16:34:01 -0400
From: Chris Snook <csnook@...hat.com>
To: "Kok, Auke" <auke-jan.h.kok@...el.com>
CC: jeff@...zik.org, jacliburn@...lsouth.net, john.ronciak@...el.com,
jesse.brandeburg@...el.com, netdev@...r.kernel.org
Subject: Re: [PATCH 2/3] remove irq_sem from e1000
Kok, Auke wrote:
> Chris Snook wrote:
>> From: Chris Snook <csnook@...hat.com>
>>
>> Remove unnecessary irq_sem accounting from e1000. Tested with no
>> problems.
>
>
> the major problem with this is that one of the e1000 parts (82547) still
> requires the irq_sem. I doubt that you tested that card specifically.
> I'm still not convinced that this patch is therefore a good idea. the
> patch for ixgb is another thing, but for e1000 we definately want to
> keep the irq_sem around until we get some definitive testing on all
> adapters.
>
> So, this patch will stay under suspicion a bit longer. Same for the ixgb
> version.
>
> Auke
Requires? I acknowledge that the code is used in a special codepath for
those cards, but it appears to be used in the same unnecessary way it is
used everywhere else.
My testing was limited to an onboard NIC on a fairly old box I don't
have access to anymore, as well as the e1000-derived atl1 driver. My
primary justification is code inspection. The code just doesn't do
anything productive.
-- Chris
>>
>> Signed-off-by: Chris Snook <csnook@...hat.com>
>> --
>> diff -urp linux-2.6.20-git14.orig/drivers/net/e1000/e1000.h
>> linux-2.6.20-git14/drivers/net/e1000/e1000.h
>> --- linux-2.6.20-git14.orig/drivers/net/e1000/e1000.h 2007-02-19
>> 14:32:15.000000000 -0500
>> +++ linux-2.6.20-git14/drivers/net/e1000/e1000.h 2007-02-19
>> 15:07:37.000000000
>> -0500
>> @@ -252,7 +252,6 @@ struct e1000_adapter {
>> #ifdef CONFIG_E1000_NAPI
>> spinlock_t tx_queue_lock;
>> #endif
>> - atomic_t irq_sem;
>> unsigned int total_tx_bytes;
>> unsigned int total_tx_packets;
>> unsigned int total_rx_bytes;
>> diff -urp linux-2.6.20-git14.orig/drivers/net/e1000/e1000_main.c
>> linux-2.6.20-git14/drivers/net/e1000/e1000_main.c
>> --- linux-2.6.20-git14.orig/drivers/net/e1000/e1000_main.c 2007-02-19
>> 14:32:15.000000000 -0500
>> +++ linux-2.6.20-git14/drivers/net/e1000/e1000_main.c 2007-02-19
>> 15:09:28.000000000 -0500
>> @@ -349,7 +349,6 @@ static void e1000_free_irq(struct e1000_
>> static void
>> e1000_irq_disable(struct e1000_adapter *adapter)
>> {
>> - atomic_inc(&adapter->irq_sem);
>> E1000_WRITE_REG(&adapter->hw, IMC, ~0);
>> E1000_WRITE_FLUSH(&adapter->hw);
>> synchronize_irq(adapter->pdev->irq);
>> @@ -363,10 +362,8 @@ e1000_irq_disable(struct e1000_adapter *
>> static void
>> e1000_irq_enable(struct e1000_adapter *adapter)
>> {
>> - if (likely(atomic_dec_and_test(&adapter->irq_sem))) {
>> - E1000_WRITE_REG(&adapter->hw, IMS, IMS_ENABLE_MASK);
>> - E1000_WRITE_FLUSH(&adapter->hw);
>> - }
>> + E1000_WRITE_REG(&adapter->hw, IMS, IMS_ENABLE_MASK);
>> + E1000_WRITE_FLUSH(&adapter->hw);
>> }
>>
>> static void
>> @@ -1336,7 +1333,6 @@ e1000_sw_init(struct e1000_adapter *adap
>> spin_lock_init(&adapter->tx_queue_lock);
>> #endif
>>
>> - atomic_set(&adapter->irq_sem, 1);
>> spin_lock_init(&adapter->stats_lock);
>>
>> set_bit(__E1000_DOWN, &adapter->flags);
>> @@ -3758,11 +3754,6 @@ e1000_intr_msi(int irq, void *data)
>> #endif
>> uint32_t icr = E1000_READ_REG(hw, ICR);
>>
>> -#ifdef CONFIG_E1000_NAPI
>> - /* read ICR disables interrupts using IAM, so keep up with our
>> - * enable/disable accounting */
>> - atomic_inc(&adapter->irq_sem);
>> -#endif
>> if (icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC)) {
>> hw->get_link_status = 1;
>> /* 80003ES2LAN workaround-- For packet buffer work-around on
>> @@ -3832,13 +3823,6 @@ e1000_intr(int irq, void *data)
>> if (unlikely(hw->mac_type >= e1000_82571 &&
>> !(icr & E1000_ICR_INT_ASSERTED)))
>> return IRQ_NONE;
>> -
>> - /* Interrupt Auto-Mask...upon reading ICR,
>> - * interrupts are masked. No need for the
>> - * IMC write, but it does mean we should
>> - * account for it ASAP. */
>> - if (likely(hw->mac_type >= e1000_82571))
>> - atomic_inc(&adapter->irq_sem);
>> #endif
>>
>> if (unlikely(icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC))) {
>> @@ -3862,7 +3846,6 @@ e1000_intr(int irq, void *data)
>> #ifdef CONFIG_E1000_NAPI
>> if (unlikely(hw->mac_type < e1000_82571)) {
>> /* disable interrupts, without the synchronize_irq bit */
>> - atomic_inc(&adapter->irq_sem);
>> E1000_WRITE_REG(hw, IMC, ~0);
>> E1000_WRITE_FLUSH(hw);
>> }
>> @@ -3888,7 +3871,6 @@ e1000_intr(int irq, void *data)
>> * de-assertion state.
>> */
>> if (hw->mac_type == e1000_82547 || hw->mac_type ==
>> e1000_82547_rev_2) {
>> - atomic_inc(&adapter->irq_sem);
>> E1000_WRITE_REG(hw, IMC, ~0);
>> }
>>
>> -
>> To unsubscribe from this list: send the line "unsubscribe netdev" in
>> the body of a message to majordomo@...r.kernel.org
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists