Subject: Re: [PATCH v4 1/3] ibmvscsi: make parameters max_id and max_channel
 read-only
To: James Bottomley <James.Bottomley@HansenPartnership.com>
References: <1447080465-17858-1-git-send-email-lvivier@redhat.com>
 <1447080465-17858-2-git-send-email-lvivier@redhat.com>
 <1447081665.2242.5.camel@HansenPartnership.com>
Cc: martin.petersen@oracle.com, hare@suse.de, brking@linux.vnet.ibm.com,
        tyreld@linux.vnet.ibm.com, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org
From: Laurent Vivier <lvivier@redhat.com>
Message-ID: <5640B9F2.4010108@redhat.com>
Date: Mon, 9 Nov 2015 16:21:22 +0100
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On 09/11/2015 16:07, James Bottomley wrote:
> On Mon, 2015-11-09 at 15:47 +0100, Laurent Vivier wrote:
>> The value of the parameter is never re-read by the driver,
>> so a new value is ignored. Let know the user he
>> can't modify it by removing writable attribute.
> 
> This isn't correct.  They're read in every time a new SCSI host is
> bound.  I don't believe VIO is a hot plug bus, so the only way to get
> the values to propagate is to unbind and rebind the driver.  Now if you
> want to argue they should be read only because users are getting
> confused about how to propagate the values, that's a different story,

Yes, but the user was me and it is easy to confuse me...

> but this is a standard pattern in quite a few drivers, so you'd need to
> argue why vscsi users are special.

vscsi users are not special, I'll remove this patch from the series.

thanks,
Laurent

> James
> 
>> Signed-off-by: Laurent Vivier <lvivier@redhat.com>
>> ---
>>  drivers/scsi/ibmvscsi/ibmvscsi.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
>> index 6a41c36..3e76490 100644
>> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
>> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
>> @@ -105,9 +105,9 @@ MODULE_AUTHOR("Dave Boutcher");
>>  MODULE_LICENSE("GPL");
>>  MODULE_VERSION(IBMVSCSI_VERSION);
>>  
>> -module_param_named(max_id, max_id, int, S_IRUGO | S_IWUSR);
>> +module_param_named(max_id, max_id, int, S_IRUGO);
>>  MODULE_PARM_DESC(max_id, "Largest ID value for each channel");
>> -module_param_named(max_channel, max_channel, int, S_IRUGO | S_IWUSR);
>> +module_param_named(max_channel, max_channel, int, S_IRUGO);
>>  MODULE_PARM_DESC(max_channel, "Largest channel value");
>>  module_param_named(init_timeout, init_timeout, int, S_IRUGO | S_IWUSR);
>>  MODULE_PARM_DESC(init_timeout, "Initialization timeout in seconds");
> 
> 
> 
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