Messages in this thread | | | Subject | Re: [PATCH v4 1/1] nvmem: Add support for write-only instances | From | Srinivas Kandagatla <> | Date | Wed, 18 Mar 2020 09:28:59 +0000 |
| |
On 18/03/2020 09:17, Nicholas Johnson wrote: > On Tue, Mar 17, 2020 at 02:35:44PM +0000, Srinivas Kandagatla wrote: >> >> >> On 17/03/2020 01:01, Nicholas Johnson wrote: >>> There is at least one real-world use-case for write-only nvmem >>> instances. Refer to 03cd45d2e219 ("thunderbolt: Prevent crash if >>> non-active NVMem file is read"). >>> >>> Add support for write-only nvmem instances by adding attrs for 0200. >>> >>> Change nvmem_register() to abort if NULL group is returned from >>> nvmem_sysfs_get_groups(). >>> >>> Return NULL from nvmem_sysfs_get_groups() in invalid cases. >>> >>> Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> >>> --- >>> drivers/nvmem/core.c | 9 ++++-- >>> drivers/nvmem/nvmem-sysfs.c | 56 +++++++++++++++++++++++++++++++------ >>> 2 files changed, 54 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c >>> index ef326f243..95ea9a3b2 100644 >>> --- a/drivers/nvmem/core.c >>> +++ b/drivers/nvmem/core.c >>> @@ -373,6 +373,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) >>> nvmem->type = config->type; >>> nvmem->reg_read = config->reg_read; >>> nvmem->reg_write = config->reg_write; >>> + nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config); >>> + if (!nvmem->dev.groups) { >>> + kfree(nvmem); >>> + return ERR_PTR(-EINVAL); >> >> When I meant leaking here, not just memory but other resources like idr and >> gpio. >> >> You should do something like this: >> >> if (!nvmem->dev.groups) { >> ida_simple_remove(&nvmem_ida, nvmem->id); >> gpiod_put(nvmem->wp_gpio); >> kfree(nvmem); >> return ERR_PTR(-EINVAL); >> } > Thanks. I am guessing these are called indirectly when there are other > failures (goto err_*). We have ida_simple_remove() in nvmem_release() > but I cannot find gpiod_put anywhere in drivers/nvmem. Because you are returning here before device intialize, you would need to do the cleanup.
Latest changes are available in linux-next or https://git.kernel.org/pub/scm/linux/kernel/git/srini/nvmem.git/tree/drivers/nvmem/core.c?h=for-next
Please rebase your patches on top of this branch, so its easy for me to apply without conflicts.
--srini > >> >>> + } >>> + >>> if (!config->no_of_node) >>> nvmem->dev.of_node = config->dev->of_node; >>> @@ -387,8 +393,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) >>> nvmem->read_only = device_property_present(config->dev, "read-only") || >>> config->read_only || !nvmem->reg_write; >>> - nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config); >>> - >>> device_initialize(&nvmem->dev); >>> dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); >>> @@ -430,7 +434,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) >>> device_del(&nvmem->dev); >>> err_put_device: >>> put_device(&nvmem->dev); >>> - >> unnecessary cleanup here! > Sorry, I let this mistake slip, despite checking my work. > >> >> Other than that every thing looks good to me! >> >> >> --srini > > Cheers, > Nicholas >> >>> return ERR_PTR(rval); >>> } >>> EXPORT_SYMBOL_GPL(nvmem_register); >>> diff --git a/drivers/nvmem/nvmem-sysfs.c b/drivers/nvmem/nvmem-sysfs.c >>> index 9e0c429cd..4ceac8680 100644 >>> --- a/drivers/nvmem/nvmem-sysfs.c >>> +++ b/drivers/nvmem/nvmem-sysfs.c >>> @@ -196,16 +196,49 @@ static const struct attribute_group *nvmem_ro_root_dev_groups[] = { >>> NULL, >>> }; >>> +/* write only permission, root only */ >>> +static struct bin_attribute bin_attr_wo_root_nvmem = { >>> + .attr = { >>> + .name = "nvmem", >>> + .mode = 0200, >>> + }, >>> + .write = bin_attr_nvmem_write, >>> +}; >>> + >>> +static struct bin_attribute *nvmem_bin_wo_root_attributes[] = { >>> + &bin_attr_wo_root_nvmem, >>> + NULL, >>> +}; >>> + >>> +static const struct attribute_group nvmem_bin_wo_root_group = { >>> + .bin_attrs = nvmem_bin_wo_root_attributes, >>> + .attrs = nvmem_attrs, >>> +}; >>> + >>> +static const struct attribute_group *nvmem_wo_root_dev_groups[] = { >>> + &nvmem_bin_wo_root_group, >>> + NULL, >>> +}; >>> + >>> const struct attribute_group **nvmem_sysfs_get_groups( >>> struct nvmem_device *nvmem, >>> const struct nvmem_config *config) >>> { >>> - if (config->root_only) >>> - return nvmem->read_only ? >>> - nvmem_ro_root_dev_groups : >>> - nvmem_rw_root_dev_groups; >>> + /* Read-only */ >>> + if (nvmem->reg_read && (!nvmem->reg_write || nvmem->read_only)) >>> + return config->root_only ? >>> + nvmem_ro_root_dev_groups : nvmem_ro_dev_groups; >>> + >>> + /* Read-write */ >>> + if (nvmem->reg_read && nvmem->reg_write && !nvmem->read_only) >>> + return config->root_only ? >>> + nvmem_rw_root_dev_groups : nvmem_rw_dev_groups; >>> + >>> + /* Write-only, do not honour request for global writable entry */ >>> + if (!nvmem->reg_read && nvmem->reg_write && !nvmem->read_only) >>> + return config->root_only ? nvmem_wo_root_dev_groups : NULL; >>> - return nvmem->read_only ? nvmem_ro_dev_groups : nvmem_rw_dev_groups; >>> + return NULL; >>> } >>> /* >>> @@ -224,17 +257,24 @@ int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem, >>> if (!config->base_dev) >>> return -EINVAL; >>> - if (nvmem->read_only) { >>> + if (nvmem->reg_read && (!nvmem->reg_write || nvmem->read_only)) { >>> if (config->root_only) >>> nvmem->eeprom = bin_attr_ro_root_nvmem; >>> else >>> nvmem->eeprom = bin_attr_ro_nvmem; >>> - } else { >>> + } else if (!nvmem->reg_read && nvmem->reg_write && !nvmem->read_only) { >>> + if (config->root_only) >>> + nvmem->eeprom = bin_attr_wo_root_nvmem; >>> + else >>> + return -EINVAL; >>> + } else if (nvmem->reg_read && nvmem->reg_write && !nvmem->read_only) { >>> if (config->root_only) >>> nvmem->eeprom = bin_attr_rw_root_nvmem; >>> else >>> nvmem->eeprom = bin_attr_rw_nvmem; >>> - } >>> + } else >>> + return -EINVAL; >>> + >>> nvmem->eeprom.attr.name = "eeprom"; >>> nvmem->eeprom.size = nvmem->size; >>> #ifdef CONFIG_DEBUG_LOCK_ALLOC >>>
| |