[ 24/72] sfc: Avoid generating over-length MC_CMD_FLUSH_RX_QUEUES request

Greg Kroah-Hartman
2013-03-26T22:52:21Z

From: Ben Hutchings <bhutchings@solarflare.com>

[ Upstream commit 450783747f42dfa3883920acfad4acdd93ce69af ]

MCDI supports requests up to 252 bytes long, which is only enough to
pass 63 RX queue IDs to MC_CMD_FLUSH_RX_QUEUES. However a VF may have
up to 64 RX queues, and if we try to flush them all we will generate
an over-length request and BUG() in efx_mcdi_copyin(). Currently
all VF drivers limit themselves to 32 RX queues, so reducing the
limit to 63 does no harm.

Also add a BUILD_BUG_ON in efx_mcdi_flush_rxqs() so we remember to
deal with the same problem there if EFX_MAX_CHANNELS is increased.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/sfc/mcdi.c | 3 +++
drivers/net/ethernet/sfc/siena_sriov.c | 7 +++++++
2 files changed, 10 insertions(+)

--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -1168,6 +1168,9 @@ int efx_mcdi_flush_rxqs(struct efx_nic *
__le32 *qid;
int rc, count;

+ BUILD_BUG_ON(EFX_MAX_CHANNELS >
+ MC_CMD_FLUSH_RX_QUEUES_IN_QID_OFST_MAXNUM);
+
qid = kmalloc(EFX_MAX_CHANNELS * sizeof(*qid), GFP_KERNEL);
if (qid == NULL)
return -ENOMEM;
--- a/drivers/net/ethernet/sfc/siena_sriov.c
+++ b/drivers/net/ethernet/sfc/siena_sriov.c
@@ -21,6 +21,9 @@
/* Number of longs required to track all the VIs in a VF */
#define VI_MASK_LENGTH BITS_TO_LONGS(1 << EFX_VI_SCALE_MAX)

+/* Maximum number of RX queues supported */
+#define VF_MAX_RX_QUEUES 63
+
/**
* enum efx_vf_tx_filter_mode - TX MAC filtering behaviour
* @VF_TX_FILTER_OFF: Disabled
@@ -578,6 +581,7 @@ static int efx_vfdi_init_rxq(struct efx_
efx_oword_t reg;

if (bad_vf_index(efx, vf_evq) || bad_vf_index(efx, vf_rxq) ||
+ vf_rxq >= VF_MAX_RX_QUEUES ||
bad_buf_count(buf_count, EFX_MAX_DMAQ_SIZE)) {
if (net_ratelimit())
netif_err(efx, hw, efx->net_dev,
@@ -683,6 +687,9 @@ static int efx_vfdi_fini_all_queues(stru
__le32 *rxqs;
int rc;

+ BUILD_BUG_ON(VF_MAX_RX_QUEUES >
+ MC_CMD_FLUSH_RX_QUEUES_IN_QID_OFST_MAXNUM);
+
rxqs = kmalloc(count * sizeof(*rxqs), GFP_KERNEL);
if (rxqs == NULL)
return VFDI_RC_ENOMEM;