[PATCH v2 net-next 04/15] sfc: don't try to create more channels than we can have VIs

[Edward Cree]

Calculate efx->max_vis at probe time, and check against it in
 efx_allocate_msix_channels() when considering whether to create XDP TX
 channels.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 drivers/net/ethernet/sfc/ef10.c         | 18 ++++++++++++++----
 drivers/net/ethernet/sfc/efx_channels.c |  7 +++++++
 drivers/net/ethernet/sfc/net_driver.h   |  1 +
 drivers/net/ethernet/sfc/siena.c        |  1 +
 4 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 4b0e3695a71a..c99fedb315fe 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -601,10 +601,14 @@ static int efx_ef10_probe(struct efx_nic *efx)
         * However, until we use TX option descriptors we need two TX queues
         * per channel.
         */
-       efx->max_channels = min_t(unsigned int,
-                                 EFX_MAX_CHANNELS,
-                                 efx_ef10_mem_map_size(efx) /
-                                 (efx->vi_stride * EFX_TXQ_TYPES));
+       efx->max_vis = efx_ef10_mem_map_size(efx) / efx->vi_stride;
+       if (!efx->max_vis) {
+               netif_err(efx, drv, efx->net_dev, "error determining max 
VIs\n");
+               rc = -EIO;
+               goto fail5;
+       }
+       efx->max_channels = min_t(unsigned int, EFX_MAX_CHANNELS,
+                                 efx->max_vis / EFX_TXQ_TYPES);
        efx->max_tx_channels = efx->max_channels;
        if (WARN_ON(efx->max_channels == 0)) {
                rc = -EIO;
@@ -1129,6 +1133,12 @@ static int efx_ef10_dimension_resources(struct efx_nic 
*efx)
                          ((efx->n_tx_channels + efx->n_extra_tx_channels) *
                           EFX_TXQ_TYPES) +
                           efx->n_xdp_channels * efx->xdp_tx_per_channel);
+       if (efx->max_vis && efx->max_vis < channel_vis) {
+               netif_dbg(efx, drv, efx->net_dev,
+                         "Reducing channel VIs from %u to %u\n",
+                         channel_vis, efx->max_vis);
+               channel_vis = efx->max_vis;
+       }
 
 #ifdef EFX_USE_PIO
        /* Try to allocate PIO buffers if wanted and if the full
diff --git a/drivers/net/ethernet/sfc/efx_channels.c 
b/drivers/net/ethernet/sfc/efx_channels.c
index c492523b986c..2c3510b0524a 100644
--- a/drivers/net/ethernet/sfc/efx_channels.c
+++ b/drivers/net/ethernet/sfc/efx_channels.c
@@ -175,6 +175,13 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
                efx->n_xdp_channels = 0;
                efx->xdp_tx_per_channel = 0;
                efx->xdp_tx_queue_count = 0;
+       } else if (n_channels + n_xdp_tx > efx->max_vis) {
+               netif_err(efx, drv, efx->net_dev,
+                         "Insufficient resources for %d XDP TX queues (%d 
other channels, max VIs %d)\n",
+                         n_xdp_tx, n_channels, efx->max_vis);
+               efx->n_xdp_channels = 0;
+               efx->xdp_tx_per_channel = 0;
+               efx->xdp_tx_queue_count = 0;
        } else {
                efx->n_xdp_channels = n_xdp_ev;
                efx->xdp_tx_per_channel = EFX_TXQ_TYPES;
diff --git a/drivers/net/ethernet/sfc/net_driver.h 
b/drivers/net/ethernet/sfc/net_driver.h
index 1afb58feb9ab..7bc4d1cbb398 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -1022,6 +1022,7 @@ struct efx_nic {
        unsigned next_buffer_table;
 
        unsigned int max_channels;
+       unsigned int max_vis;
        unsigned int max_tx_channels;
        unsigned n_channels;
        unsigned n_rx_channels;
diff --git a/drivers/net/ethernet/sfc/siena.c b/drivers/net/ethernet/sfc/siena.c
index 891e9fb6abec..6462bbe2448a 100644
--- a/drivers/net/ethernet/sfc/siena.c
+++ b/drivers/net/ethernet/sfc/siena.c
@@ -276,6 +276,7 @@ static int siena_probe_nic(struct efx_nic *efx)
        }
 
        efx->max_channels = EFX_MAX_CHANNELS;
+       efx->max_vis = EFX_MAX_CHANNELS;
        efx->max_tx_channels = EFX_MAX_CHANNELS;
 
        efx_reado(efx, &reg, FR_AZ_CS_DEBUG);