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sfc: Rework IRQ enable/disable 

There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():

1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.

2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues.  (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)

3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers.  Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.

To fix this:

a. Introduce a software IRQ enable flag.  So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.

b. Define a new struct efx_msi_context as the context for MSIs.  This
is never reallocated and is sufficient to find the software enable
flag and the channel structure.  It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.

c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts().  The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
This commit is contained in:
Ben Hutchings 2012-10-05 23:35:41 +01:00
parent 514bedbc3a
commit d829118705
4 changed files with 119 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

105
drivers/net/ethernet/sfc/efx.c
View File

@ -191,8 +191,8 @@ MODULE_PARM_DESC(debug, "Bitmapped debugging message enable value");
*
*************************************************************************/
static void efx_start_interrupts(struct efx_nic *efx, bool may_keep_eventq);
static void efx_stop_interrupts(struct efx_nic *efx, bool may_keep_eventq);
static void efx_soft_enable_interrupts(struct efx_nic *efx);
static void efx_soft_disable_interrupts(struct efx_nic *efx);
static void efx_remove_channel(struct efx_channel *channel);
static void efx_remove_channels(struct efx_nic *efx);
static const struct efx_channel_type efx_default_channel_type;
@ -520,8 +520,8 @@ static void efx_set_channel_names(struct efx_nic *efx)
efx_for_each_channel(channel, efx)
channel->type->get_name(channel,
efx->channel_name[channel->channel],
sizeof(efx->channel_name[0]));
efx->msi_context[channel->channel].name,
sizeof(efx->msi_context[0].name));
}
static int efx_probe_channels(struct efx_nic *efx)
@ -746,7 +746,7 @@ efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
efx_device_detach_sync(efx);
efx_stop_all(efx);
efx_stop_interrupts(efx, true);
efx_soft_disable_interrupts(efx);
/* Clone channels (where possible) */
memset(other_channel, 0, sizeof(other_channel));
@ -796,7 +796,7 @@ out:
}
}
efx_start_interrupts(efx, true);
efx_soft_enable_interrupts(efx);
efx_start_all(efx);
netif_device_attach(efx->net_dev);
return rc;
@ -1329,8 +1329,50 @@ static int efx_probe_interrupts(struct efx_nic *efx)
return 0;
}
/* Enable interrupts, then probe and start the event queues */
static void efx_start_interrupts(struct efx_nic *efx, bool may_keep_eventq)
static void efx_soft_enable_interrupts(struct efx_nic *efx)
{
struct efx_channel *channel;
BUG_ON(efx->state == STATE_DISABLED);
efx->irq_soft_enabled = true;
smp_wmb();
efx_for_each_channel(channel, efx) {
if (!channel->type->keep_eventq)
efx_init_eventq(channel);
efx_start_eventq(channel);
}
efx_mcdi_mode_event(efx);
}
static void efx_soft_disable_interrupts(struct efx_nic *efx)
{
struct efx_channel *channel;
if (efx->state == STATE_DISABLED)
return;
efx_mcdi_mode_poll(efx);
efx->irq_soft_enabled = false;
smp_wmb();
if (efx->legacy_irq)
synchronize_irq(efx->legacy_irq);
efx_for_each_channel(channel, efx) {
if (channel->irq)
synchronize_irq(channel->irq);
efx_stop_eventq(channel);
if (!channel->type->keep_eventq)
efx_fini_eventq(channel);
}
}
static void efx_enable_interrupts(struct efx_nic *efx)
{
struct efx_channel *channel;
@ -1340,42 +1382,29 @@ static void efx_start_interrupts(struct efx_nic *efx, bool may_keep_eventq)
enable_irq(efx->legacy_irq);
efx->eeh_disabled_legacy_irq = false;
}
if (efx->legacy_irq)
efx->legacy_irq_enabled = true;
efx_nic_enable_interrupts(efx);
efx_for_each_channel(channel, efx) {
if (!channel->type->keep_eventq || !may_keep_eventq)
if (channel->type->keep_eventq)
efx_init_eventq(channel);
efx_start_eventq(channel);
}
efx_mcdi_mode_event(efx);
efx_soft_enable_interrupts(efx);
}
static void efx_stop_interrupts(struct efx_nic *efx, bool may_keep_eventq)
static void efx_disable_interrupts(struct efx_nic *efx)
{
struct efx_channel *channel;
if (efx->state == STATE_DISABLED)
return;
efx_mcdi_mode_poll(efx);
efx_nic_disable_interrupts(efx);
if (efx->legacy_irq) {
synchronize_irq(efx->legacy_irq);
efx->legacy_irq_enabled = false;
}
efx_soft_disable_interrupts(efx);
efx_for_each_channel(channel, efx) {
if (channel->irq)
synchronize_irq(channel->irq);
efx_stop_eventq(channel);
if (!channel->type->keep_eventq || !may_keep_eventq)
if (channel->type->keep_eventq)
efx_fini_eventq(channel);
}
efx_nic_disable_interrupts(efx);
}
static void efx_remove_interrupts(struct efx_nic *efx)
@ -2160,7 +2189,7 @@ void efx_reset_down(struct efx_nic *efx, enum reset_type method)
EFX_ASSERT_RESET_SERIALISED(efx);
efx_stop_all(efx);
efx_stop_interrupts(efx, false);
efx_disable_interrupts(efx);
mutex_lock(&efx->mac_lock);
if (efx->port_initialized && method != RESET_TYPE_INVISIBLE)
@ -2199,7 +2228,7 @@ int efx_reset_up(struct efx_nic *efx, enum reset_type method, bool ok)
efx->type->reconfigure_mac(efx);
efx_start_interrupts(efx, false);
efx_enable_interrupts(efx);
efx_restore_filters(efx);
efx_sriov_reset(efx);
@ -2464,6 +2493,8 @@ static int efx_init_struct(struct efx_nic *efx,
efx->channel[i] = efx_alloc_channel(efx, i, NULL);
if (!efx->channel[i])
goto fail;
efx->msi_context[i].efx = efx;
efx->msi_context[i].index = i;
}
EFX_BUG_ON_PARANOID(efx->type->phys_addr_channels > EFX_MAX_CHANNELS);
@ -2516,7 +2547,7 @@ static void efx_pci_remove_main(struct efx_nic *efx)
BUG_ON(efx->state == STATE_READY);
cancel_work_sync(&efx->reset_work);
efx_stop_interrupts(efx, false);
efx_disable_interrupts(efx);
efx_nic_fini_interrupt(efx);
efx_fini_port(efx);
efx->type->fini(efx);
@ -2538,7 +2569,7 @@ static void efx_pci_remove(struct pci_dev *pci_dev)
/* Mark the NIC as fini, then stop the interface */
rtnl_lock();
dev_close(efx->net_dev);
efx_stop_interrupts(efx, false);
efx_disable_interrupts(efx);
rtnl_unlock();
efx_sriov_fini(efx);
@ -2640,7 +2671,7 @@ static int efx_pci_probe_main(struct efx_nic *efx)
rc = efx_nic_init_interrupt(efx);
if (rc)
goto fail5;
efx_start_interrupts(efx, false);
efx_enable_interrupts(efx);
return 0;
@ -2761,7 +2792,7 @@ static int efx_pm_freeze(struct device *dev)
efx_device_detach_sync(efx);
efx_stop_all(efx);
efx_stop_interrupts(efx, false);
efx_disable_interrupts(efx);
}
rtnl_unlock();
@ -2776,7 +2807,7 @@ static int efx_pm_thaw(struct device *dev)
rtnl_lock();
if (efx->state != STATE_DISABLED) {
efx_start_interrupts(efx, false);
efx_enable_interrupts(efx);
mutex_lock(&efx->mac_lock);
efx->phy_op->reconfigure(efx);
@ -2879,7 +2910,7 @@ static pci_ers_result_t efx_io_error_detected(struct pci_dev *pdev,
efx_device_detach_sync(efx);
efx_stop_all(efx);
efx_stop_interrupts(efx, false);
efx_disable_interrupts(efx);
status = PCI_ERS_RESULT_NEED_RESET;
} else {

3
drivers/net/ethernet/sfc/falcon.c
View File

@ -367,6 +367,9 @@ irqreturn_t falcon_legacy_interrupt_a1(int irq, void *dev_id)
"IRQ %d on CPU %d status " EFX_OWORD_FMT "\n",
irq, raw_smp_processor_id(), EFX_OWORD_VAL(*int_ker));
if (!likely(ACCESS_ONCE(efx->irq_soft_enabled)))
return IRQ_HANDLED;
/* Check to see if we have a serious error condition */
syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
if (unlikely(syserr))

24
drivers/net/ethernet/sfc/net_driver.h
View File

@ -419,6 +419,21 @@ struct efx_channel {
struct efx_tx_queue tx_queue[EFX_TXQ_TYPES];
};
/**
* struct efx_msi_context - Context for each MSI
* @efx: The associated NIC
* @index: Index of the channel/IRQ
* @name: Name of the channel/IRQ
*
* Unlike &struct efx_channel, this is never reallocated and is always
* safe for the IRQ handler to access.
*/
struct efx_msi_context {
struct efx_nic *efx;
unsigned int index;
char name[IFNAMSIZ + 6];
};
/**
* struct efx_channel_type - distinguishes traffic and extra channels
* @handle_no_channel: Handle failure to allocate an extra channel
@ -669,7 +684,6 @@ struct vfdi_status;
* @pci_dev: The PCI device
* @type: Controller type attributes
* @legacy_irq: IRQ number
* @legacy_irq_enabled: Are IRQs enabled on NIC (INT_EN_KER register)?
* @workqueue: Workqueue for port reconfigures and the HW monitor.
* Work items do not hold and must not acquire RTNL.
* @workqueue_name: Name of workqueue
@ -686,7 +700,7 @@ struct vfdi_status;
* @tx_queue: TX DMA queues
* @rx_queue: RX DMA queues
* @channel: Channels
* @channel_name: Names for channels and their IRQs
* @msi_context: Context for each MSI
* @extra_channel_types: Types of extra (non-traffic) channels that
* should be allocated for this NIC
* @rxq_entries: Size of receive queues requested by user.
@ -709,6 +723,8 @@ struct vfdi_status;
* @rx_scatter: Scatter mode enabled for receives
* @int_error_count: Number of internal errors seen recently
* @int_error_expire: Time at which error count will be expired
* @irq_soft_enabled: Are IRQs soft-enabled? If not, IRQ handler will
* acknowledge but do nothing else.
* @irq_status: Interrupt status buffer
* @irq_zero_count: Number of legacy IRQs seen with queue flags == 0
* @irq_level: IRQ level/index for IRQs not triggered by an event queue
@ -786,7 +802,6 @@ struct efx_nic {
unsigned int port_num;
const struct efx_nic_type *type;
int legacy_irq;
bool legacy_irq_enabled;
bool eeh_disabled_legacy_irq;
struct workqueue_struct *workqueue;
char workqueue_name[16];
@ -804,7 +819,7 @@ struct efx_nic {
unsigned long reset_pending;
struct efx_channel *channel[EFX_MAX_CHANNELS];
char channel_name[EFX_MAX_CHANNELS][IFNAMSIZ + 6];
struct efx_msi_context msi_context[EFX_MAX_CHANNELS];
const struct efx_channel_type *
extra_channel_type[EFX_MAX_EXTRA_CHANNELS];
@ -835,6 +850,7 @@ struct efx_nic {
unsigned int_error_count;
unsigned long int_error_expire;
bool irq_soft_enabled;
struct efx_buffer irq_status;
unsigned irq_zero_count;
unsigned irq_level;

53
drivers/net/ethernet/sfc/nic.c
View File

@ -1567,6 +1567,7 @@ irqreturn_t efx_nic_fatal_interrupt(struct efx_nic *efx)
static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
{
struct efx_nic *efx = dev_id;
bool soft_enabled = ACCESS_ONCE(efx->irq_soft_enabled);
efx_oword_t *int_ker = efx->irq_status.addr;
irqreturn_t result = IRQ_NONE;
struct efx_channel *channel;
@ -1574,12 +1575,6 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
u32 queues;
int syserr;
/* Could this be ours? If interrupts are disabled then the
* channel state may not be valid.
*/
if (!efx->legacy_irq_enabled)
return result;
/* Read the ISR which also ACKs the interrupts */
efx_readd(efx, &reg, FR_BZ_INT_ISR0);
queues = EFX_EXTRACT_DWORD(reg, 0, 31);
@ -1595,7 +1590,7 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
}
/* Handle non-event-queue sources */
if (queues & (1U << efx->irq_level)) {
if (queues & (1U << efx->irq_level) && soft_enabled) {
syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
if (unlikely(syserr))
return efx_nic_fatal_interrupt(efx);
@ -1607,10 +1602,12 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
efx->irq_zero_count = 0;
/* Schedule processing of any interrupting queues */
efx_for_each_channel(channel, efx) {
if (queues & 1)
efx_schedule_channel_irq(channel);
queues >>= 1;
if (likely(soft_enabled)) {
efx_for_each_channel(channel, efx) {
if (queues & 1)
efx_schedule_channel_irq(channel);
queues >>= 1;
}
}
result = IRQ_HANDLED;
@ -1623,12 +1620,15 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
result = IRQ_HANDLED;
/* Ensure we schedule or rearm all event queues */
efx_for_each_channel(channel, efx) {
event = efx_event(channel, channel->eventq_read_ptr);
if (efx_event_present(event))
efx_schedule_channel_irq(channel);
else
efx_nic_eventq_read_ack(channel);
if (likely(soft_enabled)) {
efx_for_each_channel(channel, efx) {
event = efx_event(channel,
channel->eventq_read_ptr);
if (efx_event_present(event))
efx_schedule_channel_irq(channel);
else
efx_nic_eventq_read_ack(channel);
}
}
}
@ -1649,8 +1649,8 @@ static irqreturn_t efx_legacy_interrupt(int irq, void *dev_id)
*/
static irqreturn_t efx_msi_interrupt(int irq, void *dev_id)
{
struct efx_channel *channel = *(struct efx_channel **)dev_id;
struct efx_nic *efx = channel->efx;
struct efx_msi_context *context = dev_id;
struct efx_nic *efx = context->efx;
efx_oword_t *int_ker = efx->irq_status.addr;
int syserr;
@ -1658,8 +1658,11 @@ static irqreturn_t efx_msi_interrupt(int irq, void *dev_id)
"IRQ %d on CPU %d status " EFX_OWORD_FMT "\n",
irq, raw_smp_processor_id(), EFX_OWORD_VAL(*int_ker));
if (!likely(ACCESS_ONCE(efx->irq_soft_enabled)))
return IRQ_HANDLED;
/* Handle non-event-queue sources */
if (channel->channel == efx->irq_level) {
if (context->index == efx->irq_level) {
syserr = EFX_OWORD_FIELD(*int_ker, FSF_AZ_NET_IVEC_FATAL_INT);
if (unlikely(syserr))
return efx_nic_fatal_interrupt(efx);
@ -1667,7 +1670,7 @@ static irqreturn_t efx_msi_interrupt(int irq, void *dev_id)
}
/* Schedule processing of the channel */
efx_schedule_channel_irq(channel);
efx_schedule_channel_irq(efx->channel[context->index]);
return IRQ_HANDLED;
}
@ -1739,8 +1742,8 @@ int efx_nic_init_interrupt(struct efx_nic *efx)
efx_for_each_channel(channel, efx) {
rc = request_irq(channel->irq, efx_msi_interrupt,
IRQF_PROBE_SHARED, /* Not shared */
efx->channel_name[channel->channel],
&efx->channel[channel->channel]);
efx->msi_context[channel->channel].name,
&efx->msi_context[channel->channel]);
if (rc) {
netif_err(efx, drv, efx->net_dev,
"failed to hook IRQ %d\n", channel->irq);
@ -1769,7 +1772,7 @@ int efx_nic_init_interrupt(struct efx_nic *efx)
efx_for_each_channel(channel, efx) {
if (n_irqs-- == 0)
break;
free_irq(channel->irq, &efx->channel[channel->channel]);
free_irq(channel->irq, &efx->msi_context[channel->channel]);
}
fail1:
return rc;
@ -1787,7 +1790,7 @@ void efx_nic_fini_interrupt(struct efx_nic *efx)
/* Disable MSI/MSI-X interrupts */
efx_for_each_channel(channel, efx)
free_irq(channel->irq, &efx->channel[channel->channel]);
free_irq(channel->irq, &efx->msi_context[channel->channel]);
/* ACK legacy interrupt */
if (efx_nic_rev(efx) >= EFX_REV_FALCON_B0)