[PATCH] target: Allow non-supporting backends to set pi_prot_type to 0

[PATCH] target: Allow non-supporting backends to set pi_prot_type to 0

[Andy Grover]

Userspace tools assume if a value is read from configfs, it is valid
and will not cause an error if the same value is written back. The only
valid value for pi_prot_type for backends not supporting DIF is 0, so allow
this particular value to be set without returning an error.

Reported-by: Krzysztof Chojnowski <frirajder@gmail.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
---
 drivers/target/target_core_device.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 65001e1..382b66b 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -936,6 +936,10 @@ int se_dev_set_pi_prot_type(struct se_device *dev, int flag)
 		return 0;
 	}
 	if (!dev->transport->init_prot || !dev->transport->free_prot) {
+		/* 0 is only allowed value for non-supporting backends */
+		if (flag == 0)
+			return 0;
+
 		pr_err("DIF protection not supported by backend: %s\n",
 		       dev->transport->name);
 		return -ENOSYS;
-- 
1.9.0

Re: [PATCH] target: Allow non-supporting backends to set pi_prot_type to 0

[Sagi Grimberg]

On 4/16/2014 12:13 AM, Andy Grover wrote:
> Userspace tools assume if a value is read from configfs, it is valid
> and will not cause an error if the same value is written back. The only
> valid value for pi_prot_type for backends not supporting DIF is 0, so allow
> this particular value to be set without returning an error.
>
> Reported-by: Krzysztof Chojnowski <frirajder@gmail.com>
> Signed-off-by: Andy Grover <agrover@redhat.com>
> ---
>   drivers/target/target_core_device.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index 65001e1..382b66b 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -936,6 +936,10 @@ int se_dev_set_pi_prot_type(struct se_device *dev, int flag)
>   		return 0;
>   	}
>   	if (!dev->transport->init_prot || !dev->transport->free_prot) {
> +		/* 0 is only allowed value for non-supporting backends */
> +		if (flag == 0)
> +			return 0;
> +
>   		pr_err("DIF protection not supported by backend: %s\n",
>   		       dev->transport->name);
>   		return -ENOSYS;

Makes sense.

Reviewed-by: Sagi Grimberg <sagig@mellanox.com>

Re: [PATCH] target: Allow non-supporting backends to set pi_prot_type to 0

[Nicholas A. Bellinger]

On Tue, 2014-04-15 at 14:13 -0700, Andy Grover wrote:
> Userspace tools assume if a value is read from configfs, it is valid
> and will not cause an error if the same value is written back. The only
> valid value for pi_prot_type for backends not supporting DIF is 0, so allow
> this particular value to be set without returning an error.
> 
> Reported-by: Krzysztof Chojnowski <frirajder@gmail.com>
> Signed-off-by: Andy Grover <agrover@redhat.com>
> ---
>  drivers/target/target_core_device.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> index 65001e1..382b66b 100644
> --- a/drivers/target/target_core_device.c
> +++ b/drivers/target/target_core_device.c
> @@ -936,6 +936,10 @@ int se_dev_set_pi_prot_type(struct se_device *dev, int flag)
>  		return 0;
>  	}
>  	if (!dev->transport->init_prot || !dev->transport->free_prot) {
> +		/* 0 is only allowed value for non-supporting backends */
> +		if (flag == 0)
> +			return 0;
> +
>  		pr_err("DIF protection not supported by backend: %s\n",
>  		       dev->transport->name);
>  		return -ENOSYS;

Applied to target-pending/queue, and will merge into master as soon as
the rebase to v3.15-rc occurs.

Thanks!

--nab

Re: [PATCH] target: Allow non-supporting backends to set pi_prot_type to 0

[Jerome Martin]

Excellent, thank you Nic and Andy, that will fix the issue with 
rtslib/targetcli main branch too.

On 04/18/2014 02:14 AM, Nicholas A. Bellinger wrote:
> On Tue, 2014-04-15 at 14:13 -0700, Andy Grover wrote:
>> Userspace tools assume if a value is read from configfs, it is valid
>> and will not cause an error if the same value is written back. The only
>> valid value for pi_prot_type for backends not supporting DIF is 0, so allow
>> this particular value to be set without returning an error.
>>
>> Reported-by: Krzysztof Chojnowski <frirajder@gmail.com>
>> Signed-off-by: Andy Grover <agrover@redhat.com>
>> ---
>>   drivers/target/target_core_device.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
>> index 65001e1..382b66b 100644
>> --- a/drivers/target/target_core_device.c
>> +++ b/drivers/target/target_core_device.c
>> @@ -936,6 +936,10 @@ int se_dev_set_pi_prot_type(struct se_device *dev, int flag)
>>   		return 0;
>>   	}
>>   	if (!dev->transport->init_prot || !dev->transport->free_prot) {
>> +		/* 0 is only allowed value for non-supporting backends */
>> +		if (flag == 0)
>> +			return 0;
>> +
>>   		pr_err("DIF protection not supported by backend: %s\n",
>>   		       dev->transport->name);
>>   		return -ENOSYS;
>
> Applied to target-pending/queue, and will merge into master as soon as
> the rebase to v3.15-rc occurs.
>
> Thanks!
>
> --nab
>
>
>
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