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e1000e: Avoid receiver overrun interrupt bursts 

When e1000e_poll() is not fast enough to keep up with incoming traffic, the
adapter (when operating in msix mode) raises the Other interrupt to signal
Receiver Overrun.

This is a double problem because 1) at the moment e1000_msix_other()
assumes that it is only called in case of Link Status Change and 2) if the
condition persists, the interrupt is repeatedly raised again in quick
succession.

Ideally we would configure the Other interrupt to not be raised in case of
receiver overrun but this doesn't seem possible on this adapter. Instead,
we handle the first part of the problem by reverting to the practice of
reading ICR in the other interrupt handler, like before commit 16ecba59bc
("e1000e: Do not read ICR in Other interrupt"). Thanks to commit
0a8047ac68 ("e1000e: Fix msi-x interrupt automask") which cleared IAME
from CTRL_EXT, reading ICR doesn't interfere with RxQ0, TxQ0 interrupts
anymore. We handle the second part of the problem by not re-enabling the
Other interrupt right away when there is overrun. Instead, we wait until
traffic subsides, napi polling mode is exited and interrupts are
re-enabled.

Reported-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Fixes: 16ecba59bc ("e1000e: Do not read ICR in Other interrupt")
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Benjamin Poirier 2017-07-21 11:36:27 -07:00 committed by Jeff Kirsher
parent 19110cfbb3
commit 4aea7a5c5e
2 changed files with 26 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/net/ethernet/intel/e1000e/defines.h
View File

@ -398,6 +398,7 @@
#define E1000_ICR_LSC 0x00000004 /* Link Status Change */
#define E1000_ICR_RXSEQ 0x00000008 /* Rx sequence error */
#define E1000_ICR_RXDMT0 0x00000010 /* Rx desc min. threshold (0) */
#define E1000_ICR_RXO 0x00000040 /* Receiver Overrun */
#define E1000_ICR_RXT0 0x00000080 /* Rx timer intr (ring 0) */
#define E1000_ICR_ECCER 0x00400000 /* Uncorrectable ECC Error */
/* If this bit asserted, the driver should claim the interrupt */

33
drivers/net/ethernet/intel/e1000e/netdev.c
View File

@ -1910,14 +1910,30 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
struct net_device *netdev = data;
struct e1000_adapter *adapter = netdev_priv(netdev);
struct e1000_hw *hw = &adapter->hw;
u32 icr;
bool enable = true;
hw->mac.get_link_status = true;
/* guard against interrupt when we're going down */
if (!test_bit(__E1000_DOWN, &adapter->state)) {
mod_timer(&adapter->watchdog_timer, jiffies + 1);
ew32(IMS, E1000_IMS_OTHER);
icr = er32(ICR);
if (icr & E1000_ICR_RXO) {
ew32(ICR, E1000_ICR_RXO);
enable = false;
/* napi poll will re-enable Other, make sure it runs */
if (napi_schedule_prep(&adapter->napi)) {
adapter->total_rx_bytes = 0;
adapter->total_rx_packets = 0;
__napi_schedule(&adapter->napi);
}
}
if (icr & E1000_ICR_LSC) {
ew32(ICR, E1000_ICR_LSC);
hw->mac.get_link_status = true;
/* guard against interrupt when we're going down */
if (!test_bit(__E1000_DOWN, &adapter->state))
mod_timer(&adapter->watchdog_timer, jiffies + 1);
}
if (enable && !test_bit(__E1000_DOWN, &adapter->state))
ew32(IMS, E1000_IMS_OTHER);
return IRQ_HANDLED;
}
@ -2687,7 +2703,8 @@ static int e1000e_poll(struct napi_struct *napi, int weight)
napi_complete_done(napi, work_done);
if (!test_bit(__E1000_DOWN, &adapter->state)) {
if (adapter->msix_entries)
ew32(IMS, adapter->rx_ring->ims_val);
ew32(IMS, adapter->rx_ring->ims_val |
E1000_IMS_OTHER);
else
e1000_irq_enable(adapter);
}
@ -4204,7 +4221,7 @@ static void e1000e_trigger_lsc(struct e1000_adapter *adapter)
struct e1000_hw *hw = &adapter->hw;
if (adapter->msix_entries)
ew32(ICS, E1000_ICS_OTHER);
ew32(ICS, E1000_ICS_LSC | E1000_ICS_OTHER);
else
ew32(ICS, E1000_ICS_LSC);
}