net: sfc: Replace in_interrupt() usage

efx_ef10_try_update_nic_stats_vf() used in_interrupt() to figure out
whether it is safe to sleep (for MCDI) or not.

The only caller from which it was not is efx_net_stats(), which can be
invoked under dev_base_lock from net-sysfs::netstat_show().

So add a new update_stats_atomic() method to struct efx_nic_type, and call
it from efx_net_stats(), removing the need for
efx_ef10_try_update_nic_stats_vf() to behave differently for this case
(which it wasn't doing correctly anyway).

For all nic_types other than EF10 VF, this method is NULL so the the
regular update_stats() methods are invoked , which are happy with being
called from atomic contexts.

Fixes: f00bf2305cab ("sfc: don't update stats on VF when called in atomic context")
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Martin Habets <mhabets@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index c9df2e9..b702ba5 100644 (file)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1871,15 +1871,6 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
 
        spin_unlock_bh(&efx->stats_lock);
 
-       if (in_interrupt()) {
-               /* If in atomic context, cannot update stats.  Just update the
-                * software stats and return so the caller can continue.
-                */
-               spin_lock_bh(&efx->stats_lock);
-               efx_update_sw_stats(efx, stats);
-               return 0;
-       }
-
        efx_ef10_get_stat_mask(efx, mask);
 
        rc = efx_nic_alloc_buffer(efx, &stats_buf, dma_len, GFP_ATOMIC);
@@ -1938,6 +1929,18 @@ static size_t efx_ef10_update_stats_vf(struct efx_nic *efx, u64 *full_stats,
        return efx_ef10_update_stats_common(efx, full_stats, core_stats);
 }
 
+static size_t efx_ef10_update_stats_atomic_vf(struct efx_nic *efx, u64 *full_stats,
+                                             struct rtnl_link_stats64 *core_stats)
+{
+       struct efx_ef10_nic_data *nic_data = efx->nic_data;
+
+       /* In atomic context, cannot update HW stats.  Just update the
+        * software stats and return so the caller can continue.
+        */
+       efx_update_sw_stats(efx, nic_data->stats);
+       return efx_ef10_update_stats_common(efx, full_stats, core_stats);
+}
+
 static void efx_ef10_push_irq_moderation(struct efx_channel *channel)
 {
        struct efx_nic *efx = channel->efx;
@@ -3998,6 +4001,7 @@ const struct efx_nic_type efx_hunt_a0_vf_nic_type = {
        .finish_flr = efx_port_dummy_op_void,
        .describe_stats = efx_ef10_describe_stats,
        .update_stats = efx_ef10_update_stats_vf,
+       .update_stats_atomic = efx_ef10_update_stats_atomic_vf,
        .start_stats = efx_port_dummy_op_void,
        .pull_stats = efx_port_dummy_op_void,
        .stop_stats = efx_port_dummy_op_void,

diff --git a/drivers/net/ethernet/sfc/efx_common.c b/drivers/net/ethernet/sfc/efx_common.c
index c256db2..72a3f0e 100644 (file)
--- a/drivers/net/ethernet/sfc/efx_common.c
+++ b/drivers/net/ethernet/sfc/efx_common.c
@@ -602,7 +602,7 @@ void efx_net_stats(struct net_device *net_dev, struct rtnl_link_stats64 *stats)
        struct efx_nic *efx = netdev_priv(net_dev);
 
        spin_lock_bh(&efx->stats_lock);
-       efx->type->update_stats(efx, NULL, stats);
+       efx_nic_update_stats_atomic(efx, NULL, stats);
        spin_unlock_bh(&efx->stats_lock);
 }
 

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 47aa753..9f7dfdf 100644 (file)
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -1172,6 +1172,9 @@ struct efx_udp_tunnel {
  * @describe_stats: Describe statistics for ethtool
  * @update_stats: Update statistics not provided by event handling.
  *     Either argument may be %NULL.
+ * @update_stats_atomic: Update statistics while in atomic context, if that
+ *     is more limiting than @update_stats.  Otherwise, leave %NULL and
+ *     driver core will call @update_stats.
  * @start_stats: Start the regular fetching of statistics
  * @pull_stats: Pull stats from the NIC and wait until they arrive.
  * @stop_stats: Stop the regular fetching of statistics
@@ -1316,6 +1319,8 @@ struct efx_nic_type {
        size_t (*describe_stats)(struct efx_nic *efx, u8 *names);
        size_t (*update_stats)(struct efx_nic *efx, u64 *full_stats,
                               struct rtnl_link_stats64 *core_stats);
+       size_t (*update_stats_atomic)(struct efx_nic *efx, u64 *full_stats,
+                                     struct rtnl_link_stats64 *core_stats);
        void (*start_stats)(struct efx_nic *efx);
        void (*pull_stats)(struct efx_nic *efx);
        void (*stop_stats)(struct efx_nic *efx);

diff --git a/drivers/net/ethernet/sfc/nic_common.h b/drivers/net/ethernet/sfc/nic_common.h
index 82271f0..b9cafe9 100644 (file)
--- a/drivers/net/ethernet/sfc/nic_common.h
+++ b/drivers/net/ethernet/sfc/nic_common.h
@@ -244,6 +244,13 @@ void efx_nic_update_stats(const struct efx_hw_stat_desc *desc, size_t count,
                          const unsigned long *mask, u64 *stats,
                          const void *dma_buf, bool accumulate);
 void efx_nic_fix_nodesc_drop_stat(struct efx_nic *efx, u64 *stat);
+static inline size_t efx_nic_update_stats_atomic(struct efx_nic *efx, u64 *full_stats,
+                                                struct rtnl_link_stats64 *core_stats)
+{
+       if (efx->type->update_stats_atomic)
+               return efx->type->update_stats_atomic(efx, full_stats, core_stats);
+       return efx->type->update_stats(efx, full_stats, core_stats);
+}
 
 #define EFX_MAX_FLUSH_TIME 5000