Re: [RFC PATCH V3 net-next 5/5] ethtool: Add fallback to get_module_eeprom from netlink command

[Moshe Shemesh <moshe@nvidia.com>]

On 3/16/2021 12:31 AM, Don Bollinger wrote:
>
> On Mon, 15 Mar 2021 10:12:39 +0700 Moshe Shemesh wrote:
>> From: Vladyslav Tarasiuk <vladyslavt@nvidia.com>
>>
>> In case netlink get_module_eeprom_data_by_page() callback is not
>> implemented by the driver, try to call old get_module_info() and
>> get_module_eeprom() pair. Recalculate parameters to
>> get_module_eeprom() offset and len using page number and their sizes.
>> Return error if this can't be done.
>>
>> Signed-off-by: Vladyslav Tarasiuk <vladyslavt@nvidia.com>
>> ---
>>   net/ethtool/eeprom.c | 75
>> +++++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 74 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/ethtool/eeprom.c b/net/ethtool/eeprom.c index
>> e110336dc231..33ba9ecc36cb 100644
>> --- a/net/ethtool/eeprom.c
>> +++ b/net/ethtool/eeprom.c
>> @@ -25,6 +25,79 @@ struct eeprom_data_reply_data {  #define
>> EEPROM_DATA_REPDATA(__reply_base) \
>>        container_of(__reply_base, struct eeprom_data_reply_data, base)
>>
>> +static int fallback_set_params(struct eeprom_data_req_info *request,
>> +                            struct ethtool_modinfo *modinfo,
>> +                            struct ethtool_eeprom *eeprom) {
>> +     u32 offset = request->offset;
>> +     u32 length = request->length;
>> +
>> +     if (request->page) {
>> +             if (offset < 128 || offset + length >
>> ETH_MODULE_EEPROM_PAGE_LEN)
>> +                     return -EINVAL;
>> +             offset = request->page * 128 + offset;
>> +     }
>> +
>> +     if (modinfo->type == ETH_MODULE_SFF_8079 &&
>> +         request->i2c_address == 0x51)
>> +             offset += ETH_MODULE_EEPROM_PAGE_LEN;
>> +
>> +     if (!length)
>> +             length = modinfo->eeprom_len;
> Need to move this check up 11 lines, before the 'if (request->page)...'
> stanza.  You need to be doing that check against the final length.
> Otherwise you could have a request that includes a page, and a length of 0,
> which becomes a length of modinfo->eeprom_len.


Right, thanks.

>> +
>> +     if (offset >= modinfo->eeprom_len)
>> +             return -EINVAL;
>> +
>> +     if (modinfo->eeprom_len < offset + length)
>> +             length = modinfo->eeprom_len - offset;
>> +
>> +     eeprom->cmd = ETHTOOL_GMODULEEEPROM;
>> +     eeprom->len = length;
>> +     eeprom->offset = offset;
>> +
>> +     return 0;
>> +}
>> +
>> +static int eeprom_data_fallback(struct eeprom_data_req_info *request,
>> +                             struct eeprom_data_reply_data *reply,
>> +                             struct genl_info *info)
>> +{
>> +     struct net_device *dev = reply->base.dev;
>> +     struct ethtool_modinfo modinfo = {0};
>> +     struct ethtool_eeprom eeprom = {0};
>> +     u8 *data;
>> +     int err;
>> +
>> +     if ((!dev->ethtool_ops->get_module_info &&
>> +          !dev->ethtool_ops->get_module_eeprom) || request->bank) {
>> +             return -EOPNOTSUPP;
>> +     }
>> +     modinfo.cmd = ETHTOOL_GMODULEINFO;
>> +     err = dev->ethtool_ops->get_module_info(dev, &modinfo);
>> +     if (err < 0)
>> +             return err;
>> +
>> +     err = fallback_set_params(request, &modinfo, &eeprom);
>> +     if (err < 0)
>> +             return err;
>> +
>> +     data = kmalloc(eeprom.len, GFP_KERNEL);
>> +     if (!data)
>> +             return -ENOMEM;
>> +     err = dev->ethtool_ops->get_module_eeprom(dev, &eeprom,
>> data);
>> +     if (err < 0)
>> +             goto err_out;
>> +
>> +     reply->data = data;
>> +     reply->length = eeprom.len;
>> +
>> +     return 0;
>> +
>> +err_out:
>> +     kfree(data);
>> +     return err;
>> +}
>> +
>>   static int eeprom_data_prepare_data(const struct ethnl_req_info
>> *req_base,
>>                                    struct ethnl_reply_data *reply_base,
>>                                    struct genl_info *info)
>> @@ -36,7 +109,7 @@ static int eeprom_data_prepare_data(const struct
>> ethnl_req_info *req_base,
>>        int ret;
>>
>>        if (!dev->ethtool_ops->get_module_eeprom_data_by_page)
>> -             return -EOPNOTSUPP;
>> +             return eeprom_data_fallback(request, reply, info);
>>
>>        page_data.offset = request->offset;
>>        page_data.length = request->length;
>> --
>> 2.26.2