[PATCH v3] platforms/powernv: Avoid re-registration of imc debugfs directory
Nageswara R Sastry
nasastry at in.ibm.com
Thu Nov 28 21:20:36 AEDT 2019
"Anju T Sudhakar" <anju at linux.vnet.ibm.com> wrote on 27/11/2019 12:50:35
PM:
> From: "Anju T Sudhakar" <anju at linux.vnet.ibm.com>
> To: mpe at ellerman.id.au
> Cc: linuxppc-dev at lists.ozlabs.org, anju at linux.vnet.ibm.com,
> Nageswara R Sastry/India/IBM at IBMIN
> Date: 27/11/2019 12:50 PM
> Subject: [PATCH v3] platforms/powernv: Avoid re-registration of imc
> debugfs directory
>
> export_imc_mode_and_cmd() function which creates the debugfs interface
for
> imc-mode and imc-command, is invoked when each nest pmu units is
> registered.
> When the first nest pmu unit is registered, export_imc_mode_and_cmd()
> creates 'imc' directory under `/debug/powerpc/`. In the subsequent
> invocations debugfs_create_dir() function returns, since the directory
> already exists.
>
> The recent commit <c33d442328f55> (debugfs: make error message a bit more
> verbose), throws a warning if we try to invoke `debugfs_create_dir()`
> with an already existing directory name.
>
> Address this warning by making the debugfs directory registration
> in the opal_imc_counters_probe() function, i.e invoke
> export_imc_mode_and_cmd() function from the probe function.
>
> Signed-off-by: Anju T Sudhakar <anju at linux.vnet.ibm.com>
> ---
> Changes from v2 -> v3:
>
> * Invoke export_imc_mode_and_cmd(), which does the imc debugfs
> directory registration and deletion, from the probe fucntion.
> * Change the return type of imc_pmu_create() to get the
> control block address for nest units in the probe
> function
> * Remove unnecessary comments
Tested-by: Nageswara R Sastry <nasastry at in.ibm.com>
Not seeing any Kernel OOPs/warnings in dmesg
# cat /sys/kernel/debug/powerpc/imc/*
0x0000000000000000
0x0000000000000000
0x0000000000000000
0x0000000000000000
> ---
> arch/powerpc/platforms/powernv/opal-imc.c | 39 ++++++++++++
> +------------------
> 1 file changed, 16 insertions(+), 23 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/opal-imc.c b/arch/
> powerpc/platforms/powernv/opal-imc.c
> index e04b206..3b4518f 100644
> --- a/arch/powerpc/platforms/powernv/opal-imc.c
> +++ b/arch/powerpc/platforms/powernv/opal-imc.c
> @@ -59,10 +59,6 @@ static void export_imc_mode_and_cmd(struct
> device_node *node,
>
> imc_debugfs_parent = debugfs_create_dir("imc", powerpc_debugfs_root);
>
> - /*
> - * Return here, either because 'imc' directory already exists,
> - * Or failed to create a new one.
> - */
> if (!imc_debugfs_parent)
> return;
>
> @@ -135,7 +131,6 @@ static int imc_get_mem_addr_nest(struct device_node
*node,
> }
>
> pmu_ptr->imc_counter_mmaped = true;
> - export_imc_mode_and_cmd(node, pmu_ptr);
> kfree(base_addr_arr);
> kfree(chipid_arr);
> return 0;
> @@ -151,7 +146,7 @@ static int imc_get_mem_addr_nest(struct device_node
*node,
> * and domain as the inputs.
> * Allocates memory for the struct imc_pmu, sets up its domain,
> size and offsets
> */
> -static int imc_pmu_create(struct device_node *parent, int
> pmu_index, int domain)
> +static struct imc_pmu *imc_pmu_create(struct device_node *parent,
> int pmu_index, int domain)
> {
> int ret = 0;
> struct imc_pmu *pmu_ptr;
> @@ -159,27 +154,23 @@ static int imc_pmu_create(struct device_node
> *parent, int pmu_index, int domain)
>
> /* Return for unknown domain */
> if (domain < 0)
> - return -EINVAL;
> + return NULL;
>
> /* memory for pmu */
> pmu_ptr = kzalloc(sizeof(*pmu_ptr), GFP_KERNEL);
> if (!pmu_ptr)
> - return -ENOMEM;
> + return NULL;
>
> /* Set the domain */
> pmu_ptr->domain = domain;
>
> ret = of_property_read_u32(parent, "size", &pmu_ptr->
counter_mem_size);
> - if (ret) {
> - ret = -EINVAL;
> + if (ret)
> goto free_pmu;
> - }
>
> if (!of_property_read_u32(parent, "offset", &offset)) {
> - if (imc_get_mem_addr_nest(parent, pmu_ptr, offset)) {
> - ret = -EINVAL;
> + if (imc_get_mem_addr_nest(parent, pmu_ptr, offset))
> goto free_pmu;
> - }
> }
>
> /* Function to register IMC pmu */
> @@ -190,14 +181,14 @@ static int imc_pmu_create(struct device_node
> *parent, int pmu_index, int domain)
> if (pmu_ptr->domain == IMC_DOMAIN_NEST)
> kfree(pmu_ptr->mem_info);
> kfree(pmu_ptr);
> - return ret;
> + return NULL;
> }
>
> - return 0;
> + return pmu_ptr;
>
> free_pmu:
> kfree(pmu_ptr);
> - return ret;
> + return NULL;
> }
>
> static void disable_nest_pmu_counters(void)
> @@ -254,6 +245,7 @@ int get_max_nest_dev(void)
> static int opal_imc_counters_probe(struct platform_device *pdev)
> {
> struct device_node *imc_dev = pdev->dev.of_node;
> + struct imc_pmu *pmu;
> int pmu_count = 0, domain;
> bool core_imc_reg = false, thread_imc_reg = false;
> u32 type;
> @@ -269,6 +261,7 @@ static int opal_imc_counters_probe(struct
> platform_device *pdev)
> }
>
> for_each_compatible_node(imc_dev, NULL, IMC_DTB_UNIT_COMPAT) {
> + pmu = NULL;
> if (of_property_read_u32(imc_dev, "type", &type)) {
> pr_warn("IMC Device without type property\n");
> continue;
> @@ -293,9 +286,13 @@ static int opal_imc_counters_probe(struct
> platform_device *pdev)
> break;
> }
>
> - if (!imc_pmu_create(imc_dev, pmu_count, domain)) {
> - if (domain == IMC_DOMAIN_NEST)
> + pmu = imc_pmu_create(imc_dev, pmu_count, domain);
> + if (pmu != NULL) {
> + if (domain == IMC_DOMAIN_NEST) {
> + if (!imc_debugfs_parent)
> + export_imc_mode_and_cmd(imc_dev, pmu);
> pmu_count++;
> + }
> if (domain == IMC_DOMAIN_CORE)
> core_imc_reg = true;
> if (domain == IMC_DOMAIN_THREAD)
> @@ -303,10 +300,6 @@ static int opal_imc_counters_probe(struct
> platform_device *pdev)
> }
> }
>
> - /* If none of the nest units are registered, remove debugfs interface
*/
> - if (pmu_count == 0)
> - debugfs_remove_recursive(imc_debugfs_parent);
> -
> /* If core imc is not registered, unregister thread-imc */
> if (!core_imc_reg && thread_imc_reg)
> unregister_thread_imc();
> --
> 1.8.3.1
>
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