[PATCH 3.14 120/228] igb: Unset IGB_FLAG_HAS_MSIX-flag when falling back to msi-only

Greg Kroah-Hartman
2014-06-05T00:25:45Z

From: Christoph Paasch <christoph.paasch@uclouvain.be>

commit b709323d2477614823a38c2f2a9a206e087e28fc upstream.

Prior to cd14ef54d25 (igb: Change to use statically allocated array for
MSIx entries), having msix_entries different from NULL was an indicator
that MSIX is enabled.
In igb_set_interrupt_capabiliy we may fall back to MSI-only. Prior to
the above patch msix_entries was set to NULL by
igb_reset_interrupt_capability.

However, now we are checking the flag for IGB_FLAG_HAS_MSIX and so the
stack gets completly confused:

[ 42.659791] ------------[ cut here ]------------
[ 42.715032] WARNING: CPU: 7 PID: 0 at net/sched/sch_generic.c:264 dev_watchdog+0x15c/0x1fb()
[ 42.848263] NETDEV WATCHDOG: eth0 (igb): transmit queue 0 timed out
[ 42.923253] Modules linked in:
[ 42.959875] CPU: 7 PID: 0 Comm: swapper/7 Not tainted 3.14.0-rc2-mptcp #437
[ 43.043184] Hardware name: HP ProLiant DL165 G7, BIOS O37 01/26/2011
[ 43.119215] 0000000000000108 ffff88023fdc3da8 ffffffff81487847 0000000000000108
[ 43.208165] ffff88023fdc3df8 ffff88023fdc3de8 ffffffff81034e7d ffff88023fdc3dd8
[ 43.297120] ffffffff813fff10 ffff880236018000 ffff880236b178c0 0000000000000008
[ 43.386071] Call Trace:
[ 43.415303] <IRQ> [<ffffffff81487847>] dump_stack+0x49/0x62
[ 43.484174] [<ffffffff81034e7d>] warn_slowpath_common+0x77/0x91
[ 43.556049] [<ffffffff813fff10>] ? dev_watchdog+0x15c/0x1fb
[ 43.623759] [<ffffffff81034f2b>] warn_slowpath_fmt+0x41/0x43
[ 43.692511] [<ffffffff813fff10>] dev_watchdog+0x15c/0x1fb
[ 43.758141] [<ffffffff813ffdb4>] ? __netdev_watchdog_up+0x64/0x64
[ 43.832091] [<ffffffff8103cd04>] call_timer_fn+0x17/0x6f
[ 43.896682] [<ffffffff8103cebe>] run_timer_softirq+0x162/0x1a2
[ 43.967511] [<ffffffff81038520>] __do_softirq+0xcd/0x1cc
[ 44.032104] [<ffffffff81038689>] irq_exit+0x3a/0x48
[ 44.091492] [<ffffffff81026d43>] smp_apic_timer_interrupt+0x43/0x50
[ 44.167525] [<ffffffff8148c24a>] apic_timer_interrupt+0x6a/0x70
[ 44.239392] <EOI> [<ffffffff8100992c>] ? default_idle+0x6/0x8
[ 44.310343] [<ffffffff81009b31>] arch_cpu_idle+0x13/0x18
[ 44.374934] [<ffffffff81066126>] cpu_startup_entry+0xa7/0x101
[ 44.444724] [<ffffffff81025660>] start_secondary+0x1b2/0x1b7
[ 44.513472] ---[ end trace a5a075fd4e7f854f ]---
[ 44.568753] igb 0000:04:00.0 eth0: Reset adapter
[ 46.206945] random: nonblocking pool is initialized
[ 46.465670] irq 44: nobody cared (try booting with the "irqpoll" option)
[ 46.545862] CPU: 7 PID: 0 Comm: swapper/7 Tainted: G W 3.14.0-rc2-mptcp #437
[ 46.640610] Hardware name: HP ProLiant DL165 G7, BIOS O37 01/26/2011
[ 46.716641] ffff8802363f8c84 ffff88023fdc3e38 ffffffff81487847 00000000a03cdb6d
[ 46.805598] ffff8802363f8c00 ffff88023fdc3e68 ffffffff81068489 0000007f81825400
[ 46.894539] ffff8802363f8c00 0000000000000000 0000000000000000 ffff88023fdc3ea8
[ 46.983484] Call Trace:
[ 47.012714] <IRQ> [<ffffffff81487847>] dump_stack+0x49/0x62
[ 47.081585] [<ffffffff81068489>] __report_bad_irq+0x35/0xc1
[ 47.149295] [<ffffffff81068683>] note_interrupt+0x16e/0x1ea
[ 47.217006] [<ffffffff8106679e>] handle_irq_event_percpu+0x116/0x12e
[ 47.294075] [<ffffffff810667e9>] handle_irq_event+0x33/0x4f
[ 47.361787] [<ffffffff81068c95>] handle_fasteoi_irq+0x83/0xd1
[ 47.431577] [<ffffffff81003d5b>] handle_irq+0x1f/0x28
[ 47.493047] [<ffffffff81003567>] do_IRQ+0x4e/0xd4
[ 47.550358] [<ffffffff8148b06a>] common_interrupt+0x6a/0x6a
[ 47.618066] <EOI> [<ffffffff8100992c>] ? default_idle+0x6/0x8
[ 47.689016] [<ffffffff81009b31>] arch_cpu_idle+0x13/0x18
[ 47.753605] [<ffffffff81066126>] cpu_startup_entry+0xa7/0x101
[ 47.823397] [<ffffffff81025660>] start_secondary+0x1b2/0x1b7
[ 47.892146] handlers:
[ 47.919301] [<ffffffff812fbd7d>] igb_intr

So, this patch unsets the flag to indicate that we are not using MSIX.
This patch does exactly this: Unsetting the flag when falling back to MSI.

Fixes: cd14ef54d25b (igb: Change to use statically allocated array for MSIx entries)
Cc: Carolyn Wyborny <carolyn.wyborny@intel.com>
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/intel/igb/igb_main.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -1127,6 +1127,7 @@ static void igb_set_interrupt_capability

/* If we can't do MSI-X, try MSI */
msi_only:
+ adapter->flags &= ~IGB_FLAG_HAS_MSIX;
#ifdef CONFIG_PCI_IOV
/* disable SR-IOV for non MSI-X configurations */
if (adapter->vf_data) {