sfc: don't update stats on VF when called in atomic context

The ifenslave command to set up a bond runs in an atomic
context, and it queries the stats on the devices that are
being enslaved. A VF needs to make an MCDI call to update
its stats, which is not allowed in atomic context.

The releasing of the stats_lock is moved to the beginning of
the VF stats update function so that in_interrupt() can be
used; it must be taken again before returning from this
function.

Signed-off-by: Shradha Shah <sshah@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 03f464f..6b8d8f2 100644 (file)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1306,11 +1306,24 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
        __le64 *dma_stats;
        int rc;
 
+       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);
-       if (rc)
+       if (rc) {
+               spin_lock_bh(&efx->stats_lock);
                return rc;
+       }
 
        dma_stats = stats_buf.addr;
        dma_stats[MC_CMD_MAC_GENERATION_END] = EFX_MC_STATS_GENERATION_INVALID;
@@ -1321,7 +1334,6 @@ static int efx_ef10_try_update_nic_stats_vf(struct efx_nic *efx)
        MCDI_SET_DWORD(inbuf, MAC_STATS_IN_DMA_LEN, dma_len);
        MCDI_SET_DWORD(inbuf, MAC_STATS_IN_PORT_ID, EVB_PORT_ID_ASSIGNED);
 
-       spin_unlock_bh(&efx->stats_lock);
        rc = efx_mcdi_rpc_quiet(efx, MC_CMD_MAC_STATS, inbuf, sizeof(inbuf),
                                NULL, 0, NULL);
        spin_lock_bh(&efx->stats_lock);