Commit a7d529ae authored by Ben Hutchings's avatar Ben Hutchings
Browse files

sfc: Allow resets to be upgraded; use atomic ops for safety 



Currently an attempt to schedule any reset is ignored if a reset
is already pending.  This ignores the relative scopes - if the
requested reset is greater in scope then the scheduled reset should
be upgraded accordingly.

There are also some race conditions which could lead to a reset
request being lost.  Deal with them by using atomic operations on a
bitmask.  This also makes tests on reset_pending easier to get right.

Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
parent 4017dbdc

drivers/net/sfc/efx.c

+17 −21
Original line number Diff line number Diff line
@@ -229,8 +229,7 @@ static int efx_process_channel(struct efx_channel *channel, int budget) 
	struct efx_nic *efx = channel->efx;

	int spent;



	if (unlikely(efx->reset_pending != RESET_TYPE_NONE ||

		     !channel->enabled))

	if (unlikely(efx->reset_pending || !channel->enabled))

		return 0;



	spent = efx_nic_process_eventq(channel, budget);
@@ -1461,7 +1460,7 @@ static void efx_start_all(struct efx_nic *efx) 
	 * reset_pending [modified from an atomic context], we instead guarantee

	 * that efx_mcdi_mode_poll() isn't reverted erroneously */

	efx_mcdi_mode_event(efx);

	if (efx->reset_pending != RESET_TYPE_NONE)

	if (efx->reset_pending)

		efx_mcdi_mode_poll(efx);



	/* Start the hardware monitor if there is one. Otherwise (we're link
@@ -2118,8 +2117,10 @@ int efx_reset(struct efx_nic *efx, enum reset_type method) 
		goto out;

	}



	/* Allow resets to be rescheduled. */

	efx->reset_pending = RESET_TYPE_NONE;

	/* Clear flags for the scopes we covered.  We assume the NIC and

	 * driver are now quiescent so that there is no race here.

	 */

	efx->reset_pending &= -(1 << (method + 1));



	/* Reinitialise bus-mastering, which may have been turned off before

	 * the reset was scheduled. This is still appropriate, even in the
@@ -2154,12 +2155,13 @@ out: 
static void efx_reset_work(struct work_struct *data)

{

	struct efx_nic *efx = container_of(data, struct efx_nic, reset_work);

	unsigned long pending = ACCESS_ONCE(efx->reset_pending);



	if (efx->reset_pending == RESET_TYPE_NONE)

	if (!pending)

		return;



	/* If we're not RUNNING then don't reset. Leave the reset_pending

	 * flag set so that efx_pci_probe_main will be retried */

	 * flags set so that efx_pci_probe_main will be retried */

	if (efx->state != STATE_RUNNING) {

		netif_info(efx, drv, efx->net_dev,

			   "scheduled reset quenched. NIC not RUNNING\n");
@@ -2167,7 +2169,7 @@ static void efx_reset_work(struct work_struct *data) 
	}



	rtnl_lock();

	(void)efx_reset(efx, efx->reset_pending);

	(void)efx_reset(efx, fls(pending) - 1);

	rtnl_unlock();

}
@@ -2175,12 +2177,6 @@ void efx_schedule_reset(struct efx_nic *efx, enum reset_type type) 
{

	enum reset_type method;



	if (efx->reset_pending != RESET_TYPE_NONE) {

		netif_info(efx, drv, efx->net_dev,

			   "quenching already scheduled reset\n");

		return;

	}



	switch (type) {

	case RESET_TYPE_INVISIBLE:

	case RESET_TYPE_ALL:
@@ -2208,7 +2204,7 @@ void efx_schedule_reset(struct efx_nic *efx, enum reset_type type) 
		netif_dbg(efx, drv, efx->net_dev, "scheduling %s reset\n",

			  RESET_TYPE(method));



	efx->reset_pending = method;

	set_bit(method, &efx->reset_pending);



	/* efx_process_channel() will no longer read events once a

	 * reset is scheduled. So switch back to poll'd MCDI completions. */
@@ -2288,7 +2284,6 @@ static int efx_init_struct(struct efx_nic *efx, const struct efx_nic_type *type, 
	efx->pci_dev = pci_dev;

	efx->msg_enable = debug;

	efx->state = STATE_INIT;

	efx->reset_pending = RESET_TYPE_NONE;

	strlcpy(efx->name, pci_name(pci_dev), sizeof(efx->name));



	efx->net_dev = net_dev;
@@ -2510,7 +2505,7 @@ static int __devinit efx_pci_probe(struct pci_dev *pci_dev, 
		cancel_work_sync(&efx->reset_work);



		if (rc == 0) {

			if (efx->reset_pending != RESET_TYPE_NONE) {

			if (efx->reset_pending) {

				/* If there was a scheduled reset during

				 * probe, the NIC is probably hosed anyway */

				efx_pci_remove_main(efx);
@@ -2521,11 +2516,12 @@ static int __devinit efx_pci_probe(struct pci_dev *pci_dev, 
		}



		/* Retry if a recoverably reset event has been scheduled */

		if ((efx->reset_pending != RESET_TYPE_INVISIBLE) &&

		    (efx->reset_pending != RESET_TYPE_ALL))

		if (efx->reset_pending &

		    ~(1 << RESET_TYPE_INVISIBLE | 1 << RESET_TYPE_ALL) ||

		    !efx->reset_pending)

			goto fail3;



		efx->reset_pending = RESET_TYPE_NONE;

		efx->reset_pending = 0;

	}



	if (rc) {
@@ -2609,7 +2605,7 @@ static int efx_pm_poweroff(struct device *dev) 


	efx->type->fini(efx);



	efx->reset_pending = RESET_TYPE_NONE;

	efx->reset_pending = 0;



	pci_save_state(pci_dev);

	return pci_set_power_state(pci_dev, PCI_D3hot);

drivers/net/sfc/enum.h

+2 −1
Original line number Diff line number Diff line
@@ -134,6 +134,8 @@ enum efx_loopback_mode { 
 * other valuesspecify reasons, which efx_schedule_reset() will choose

 * a method for.

 *

 * Reset methods are numbered in order of increasing scope.

 *

 * @RESET_TYPE_INVISIBLE: don't reset the PHYs or interrupts

 * @RESET_TYPE_ALL: reset everything but PCI core blocks

 * @RESET_TYPE_WORLD: reset everything, save & restore PCI config
@@ -147,7 +149,6 @@ enum efx_loopback_mode { 
 * @RESET_TYPE_MC_FAILURE: MC reboot/assertion

 */

enum reset_type {

	RESET_TYPE_NONE = -1,

	RESET_TYPE_INVISIBLE = 0,

	RESET_TYPE_ALL = 1,

	RESET_TYPE_WORLD = 2,

drivers/net/sfc/falcon.c

+1 −1
Original line number Diff line number Diff line
@@ -536,7 +536,7 @@ void falcon_reconfigure_mac_wrapper(struct efx_nic *efx) 
	efx_oword_t reg;

	int link_speed, isolate;



	isolate = (efx->reset_pending != RESET_TYPE_NONE);

	isolate = !!ACCESS_ONCE(efx->reset_pending);



	switch (link_state->speed) {

	case 10000: link_speed = 3; break;

drivers/net/sfc/net_driver.h

+2 −2
Original line number Diff line number Diff line
@@ -645,7 +645,7 @@ struct efx_filter_state; 
 * @irq_rx_moderation: IRQ moderation time for RX event queues

 * @msg_enable: Log message enable flags

 * @state: Device state flag. Serialised by the rtnl_lock.

 * @reset_pending: Pending reset method (normally RESET_TYPE_NONE)

 * @reset_pending: Bitmask for pending resets

 * @tx_queue: TX DMA queues

 * @rx_queue: RX DMA queues

 * @channel: Channels
@@ -728,7 +728,7 @@ struct efx_nic { 
	u32 msg_enable;



	enum nic_state state;

	enum reset_type reset_pending;

	unsigned long reset_pending;



	struct efx_channel *channel[EFX_MAX_CHANNELS];

	char channel_name[EFX_MAX_CHANNELS][IFNAMSIZ + 6];

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