Hello Vladimir, On Mon, Jul 08, 2024 at 04:37:46PM +0300, Vladimir Oltean wrote: > On Thu, Jun 27, 2024 at 11:40:24AM -0700, Breno Leitao wrote:
> > > > 454 | static int dpaa_set_coalesce(struct net_device *dev, > > > > | ^ > > > > 1 warning generated. > > > > > > Arrays of NR_CPUS elements are what it probably doesn't like? > > Can it use the number of online CPUs instead of NR_CPUS? > I don't see how, given that variable length arrays are something which > should be avoided in the kernel? I thought about a patch like the following (compile tested only). What do you think? Author: Breno Leitao <lei...@debian.org> Date: Mon Jul 8 11:57:33 2024 -0700 net: dpaa: Allocate only for online CPUs in dpaa_set_coalesce Currently, dpaa_set_coalesce allocates a boolean for every possible CPU (NR_CPUS). This approach is suboptimal and causes failures in COMPILE_TEST. For reference, see: https://lore.kernel.org/all/202406261920.l5pzm1rj-...@intel.com/ Modify the allocation to consider only online CPUs instead of NR_CPUs. This change reduces the function's memory footprint and resolves the COMPILE_TEST issues. Signed-off-by: Breno Leitao <lei...@debian.org> diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c b/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c index 5bd0b36d1feb..7202a5310045 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_ethtool.c @@ -457,7 +457,7 @@ 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}; + bool *needs_revert; struct qman_portal *portal; u32 period, prev_period; u8 thresh, prev_thresh; @@ -466,6 +466,11 @@ static int dpaa_set_coalesce(struct net_device *dev, period = c->rx_coalesce_usecs; thresh = c->rx_max_coalesced_frames; + needs_revert = kmalloc_array(num_possible_cpus(), sizeof(bool), GFP_KERNEL); + if (!needs_revert) + return -ENOMEM; + memset(needs_revert, 0, num_online_cpus() * sizeof(bool)); + /* save previous values */ portal = qman_get_affine_portal(smp_processor_id()); qman_portal_get_iperiod(portal, &prev_period); @@ -498,6 +503,7 @@ static int dpaa_set_coalesce(struct net_device *dev, qman_dqrr_set_ithresh(portal, prev_thresh); } + kfree(needs_revert); return res; }