5.15-stable review patch. If anyone has any objections, please let me know.
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From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit 555a05d84ca2c587e2d4777006e2c2fb3dfbd91d ]
The dpaa-eth driver is written for PowerPC and Arm SoCs which have 1-24 CPUs. It depends on CONFIG_NR_CPUS having a reasonably small value in Kconfig. Otherwise, there are 2 functions which allocate on-stack arrays of NR_CPUS elements, and these can quickly explode in size, leading to warnings such as:
drivers/net/ethernet/freescale/dpaa/dpaa_eth.c:3280:12: warning: stack frame size (16664) exceeds limit (2048) in 'dpaa_eth_probe' [-Wframe-larger-than]
The problem is twofold: - Reducing the array size to the boot-time num_possible_cpus() (rather than the compile-time NR_CPUS) creates a variable-length array, which should be avoided in the Linux kernel. - Using NR_CPUS as an array size makes the driver blow up in stack consumption with generic, as opposed to hand-crafted, .config files.
A simple solution is to use dynamic allocation for num_possible_cpus() elements (aka a small number determined at runtime).
Link: https://lore.kernel.org/all/202406261920.l5pzM1rj-lkp@intel.com/ Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Reviewed-by: Breno Leitao leitao@debian.org Acked-by: Madalin Bucur madalin.bucur@oss.nxp.com Link: https://patch.msgid.link/20240713225336.1746343-2-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../net/ethernet/freescale/dpaa/dpaa_eth.c | 20 ++++++++++++++----- .../ethernet/freescale/dpaa/dpaa_ethtool.c | 10 +++++++++- 2 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c index 1766b7d94ffa..119f560b2e65 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c @@ -910,14 +910,18 @@ static inline void dpaa_setup_egress(const struct dpaa_priv *priv, } }
-static void dpaa_fq_setup(struct dpaa_priv *priv, - const struct dpaa_fq_cbs *fq_cbs, - struct fman_port *tx_port) +static int dpaa_fq_setup(struct dpaa_priv *priv, + const struct dpaa_fq_cbs *fq_cbs, + struct fman_port *tx_port) { int egress_cnt = 0, conf_cnt = 0, num_portals = 0, portal_cnt = 0, cpu; const cpumask_t *affine_cpus = qman_affine_cpus(); - u16 channels[NR_CPUS]; struct dpaa_fq *fq; + u16 *channels; + + channels = kcalloc(num_possible_cpus(), sizeof(u16), GFP_KERNEL); + if (!channels) + return -ENOMEM;
for_each_cpu_and(cpu, affine_cpus, cpu_online_mask) channels[num_portals++] = qman_affine_channel(cpu); @@ -976,6 +980,10 @@ static void dpaa_fq_setup(struct dpaa_priv *priv, break; } } + + kfree(channels); + + return 0; }
static inline int dpaa_tx_fq_to_id(const struct dpaa_priv *priv, @@ -3444,7 +3452,9 @@ static int dpaa_eth_probe(struct platform_device *pdev) */ dpaa_eth_add_channel(priv->channel, &pdev->dev);
- dpaa_fq_setup(priv, &dpaa_fq_cbs, priv->mac_dev->port[TX]); + err = dpaa_fq_setup(priv, &dpaa_fq_cbs, priv->mac_dev->port[TX]); + if (err) + goto free_dpaa_bps;
/* Create a congestion group for this netdev, with * dynamically-allocated CGR ID. diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c b/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c index 5750f9a56393..df6af1097dd2 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c @@ -541,12 +541,16 @@ static int dpaa_set_coalesce(struct net_device *dev, struct netlink_ext_ack *extack) { const cpumask_t *cpus = qman_affine_cpus(); - bool needs_revert[NR_CPUS] = {false}; struct qman_portal *portal; u32 period, prev_period; u8 thresh, prev_thresh; + bool *needs_revert; int cpu, res;
+ needs_revert = kcalloc(num_possible_cpus(), sizeof(bool), GFP_KERNEL); + if (!needs_revert) + return -ENOMEM; + period = c->rx_coalesce_usecs; thresh = c->rx_max_coalesced_frames;
@@ -569,6 +573,8 @@ static int dpaa_set_coalesce(struct net_device *dev, needs_revert[cpu] = true; }
+ kfree(needs_revert); + return 0;
revert_values: @@ -582,6 +588,8 @@ static int dpaa_set_coalesce(struct net_device *dev, qman_dqrr_set_ithresh(portal, prev_thresh); }
+ kfree(needs_revert); + return res; }