[ 3.5.y.z extended stable ] Patch "sfc: Avoid generating over-length MC_CMD_FLUSH_RX_QUEUES" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    sfc: Avoid generating over-length MC_CMD_FLUSH_RX_QUEUES

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From dcffe86789973bb047caa06c8328d54304dc5271 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <bhutchings at solarflare.com>
Date: Wed, 19 Sep 2012 02:53:34 +0100
Subject: [PATCH] sfc: Avoid generating over-length MC_CMD_FLUSH_RX_QUEUES
 request

commit 450783747f42dfa3883920acfad4acdd93ce69af upstream.

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 at solarflare.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/ethernet/sfc/mcdi.c        | 3 +++
 drivers/net/ethernet/sfc/siena_sriov.c | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
index b49012d..a423cd3 100644
--- 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 *efx)
 	__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;
diff --git a/drivers/net/ethernet/sfc/siena_sriov.c b/drivers/net/ethernet/sfc/siena_sriov.c
index 78f5408..4ad8082 100644
--- 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_vf *vf)
 	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(struct efx_vf *vf)
 	__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;
--
1.8.1.2