[PATCH V5] Save command pool address of Scsi_Host

[PATCH V5] Save command pool address of Scsi_Host

[jgross]

From: Juergen Gross <jgross@suse.com>

If a scsi host driver specifies .cmd_len in it's scsi_host_template, a driver's
private command pool is needed. scsi_find_host_cmd_pool() will locate it, but
scsi_alloc_host_cmd_pool() isn't saving the pool address in the host template.

This will result in an access error when the host is removed.

Avoid the problem by saving the address of a new allocated command pool where
it is expected.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/scsi/scsi.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 88d46fe..b0cef5b 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -380,6 +380,10 @@ scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
 		pool->slab_flags |= SLAB_CACHE_DMA;
 		pool->gfp_mask = __GFP_DMA;
 	}
+
+	if (hostt->cmd_size)
+		hostt->cmd_pool = pool;
+
 	return pool;
 }
 
@@ -424,8 +428,10 @@ out:
 out_free_slab:
 	kmem_cache_destroy(pool->cmd_slab);
 out_free_pool:
-	if (hostt->cmd_size)
+	if (hostt->cmd_size) {
 		scsi_free_host_cmd_pool(pool);
+		hostt->cmd_pool = NULL;
+	}
 	goto out;
 }
 
@@ -447,8 +453,10 @@ static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
 	if (!--pool->users) {
 		kmem_cache_destroy(pool->cmd_slab);
 		kmem_cache_destroy(pool->sense_slab);
-		if (hostt->cmd_size)
+		if (hostt->cmd_size) {
 			scsi_free_host_cmd_pool(pool);
+			hostt->cmd_pool = NULL;
+		}
 	}
 	mutex_unlock(&host_cmd_pool_mutex);
 }
-- 
1.8.4.5

Re: [PATCH V5] Save command pool address of Scsi_Host

[Boaz Harrosh]

On 08/04/2014 02:30 PM, jgross@suse.com wrote:
> From: Juergen Gross <jgross@suse.com>
> 
> If a scsi host driver specifies .cmd_len in it's scsi_host_template, a driver's
> private command pool is needed. scsi_find_host_cmd_pool() will locate it, but
> scsi_alloc_host_cmd_pool() isn't saving the pool address in the host template.
> 
> This will result in an access error when the host is removed.
> 
> Avoid the problem by saving the address of a new allocated command pool where
> it is expected.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
>  drivers/scsi/scsi.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index 88d46fe..b0cef5b 100644
> --- a/drivers/scsi/scsi.c
> +++ b/drivers/scsi/scsi.c
> @@ -380,6 +380,10 @@ scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
>  		pool->slab_flags |= SLAB_CACHE_DMA;
>  		pool->gfp_mask = __GFP_DMA;
>  	}
> +
> +	if (hostt->cmd_size)
> +		hostt->cmd_pool = pool;
> +
>  	return pool;
>  }
>  
> @@ -424,8 +428,10 @@ out:
>  out_free_slab:
>  	kmem_cache_destroy(pool->cmd_slab);
>  out_free_pool:
> -	if (hostt->cmd_size)
> +	if (hostt->cmd_size) {
>  		scsi_free_host_cmd_pool(pool);

I disagree I liked the V4 version better. It is much nicer on the review
that we NULL the same one we pass in with no need for context that's outside
of this scope

Just my $0.017
Boaz

> +		hostt->cmd_pool = NULL;
> +	}
>  	goto out;
>  }
>  
> @@ -447,8 +453,10 @@ static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
>  	if (!--pool->users) {
>  		kmem_cache_destroy(pool->cmd_slab);
>  		kmem_cache_destroy(pool->sense_slab);
> -		if (hostt->cmd_size)
> +		if (hostt->cmd_size) {
>  			scsi_free_host_cmd_pool(pool);
> +			hostt->cmd_pool = NULL;
> +		}
>  	}
>  	mutex_unlock(&host_cmd_pool_mutex);
>  }
> 

Re: [PATCH V5] Save command pool address of Scsi_Host

[Juergen Gross]

On 08/04/2014 01:49 PM, Boaz Harrosh wrote:
> On 08/04/2014 02:30 PM, jgross@suse.com wrote:
>> From: Juergen Gross <jgross@suse.com>
>>
>> If a scsi host driver specifies .cmd_len in it's scsi_host_template, a driver's
>> private command pool is needed. scsi_find_host_cmd_pool() will locate it, but
>> scsi_alloc_host_cmd_pool() isn't saving the pool address in the host template.
>>
>> This will result in an access error when the host is removed.
>>
>> Avoid the problem by saving the address of a new allocated command pool where
>> it is expected.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>>   drivers/scsi/scsi.c | 12 ++++++++++--
>>   1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
>> index 88d46fe..b0cef5b 100644
>> --- a/drivers/scsi/scsi.c
>> +++ b/drivers/scsi/scsi.c
>> @@ -380,6 +380,10 @@ scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
>>   		pool->slab_flags |= SLAB_CACHE_DMA;
>>   		pool->gfp_mask = __GFP_DMA;
>>   	}
>> +
>> +	if (hostt->cmd_size)
>> +		hostt->cmd_pool = pool;
>> +
>>   	return pool;
>>   }
>>
>> @@ -424,8 +428,10 @@ out:
>>   out_free_slab:
>>   	kmem_cache_destroy(pool->cmd_slab);
>>   out_free_pool:
>> -	if (hostt->cmd_size)
>> +	if (hostt->cmd_size) {
>>   		scsi_free_host_cmd_pool(pool);
>
> I disagree I liked the V4 version better. It is much nicer on the review
> that we NULL the same one we pass in with no need for context that's outside
> of this scope

:-)

I'm fine with either version.

Juergen

>
> Just my $0.017
> Boaz
>
>> +		hostt->cmd_pool = NULL;
>> +	}
>>   	goto out;
>>   }
>>
>> @@ -447,8 +453,10 @@ static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
>>   	if (!--pool->users) {
>>   		kmem_cache_destroy(pool->cmd_slab);
>>   		kmem_cache_destroy(pool->sense_slab);
>> -		if (hostt->cmd_size)
>> +		if (hostt->cmd_size) {
>>   			scsi_free_host_cmd_pool(pool);
>> +			hostt->cmd_pool = NULL;
>> +		}
>>   	}
>>   	mutex_unlock(&host_cmd_pool_mutex);
>>   }
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>

Re: [PATCH V5] Save command pool address of Scsi_Host

[Christoph Hellwig]

Can I get another review for this one so I can queue it up for 3.17?
(or v4 if you have a strong preference for it..)

Re: [PATCH V5] Save command pool address of Scsi_Host

[Hannes Reinecke]

On 08/04/2014 01:30 PM, jgross@suse.com wrote:
> From: Juergen Gross <jgross@suse.com>
>
> If a scsi host driver specifies .cmd_len in it's scsi_host_template, a driver's
> private command pool is needed. scsi_find_host_cmd_pool() will locate it, but
> scsi_alloc_host_cmd_pool() isn't saving the pool address in the host template.
>
> This will result in an access error when the host is removed.
>
> Avoid the problem by saving the address of a new allocated command pool where
> it is expected.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
>   drivers/scsi/scsi.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index 88d46fe..b0cef5b 100644
> --- a/drivers/scsi/scsi.c
> +++ b/drivers/scsi/scsi.c
> @@ -380,6 +380,10 @@ scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
>   		pool->slab_flags |= SLAB_CACHE_DMA;
>   		pool->gfp_mask = __GFP_DMA;
>   	}
> +
> +	if (hostt->cmd_size)
> +		hostt->cmd_pool = pool;
> +
>   	return pool;
>   }
>
> @@ -424,8 +428,10 @@ out:
>   out_free_slab:
>   	kmem_cache_destroy(pool->cmd_slab);
>   out_free_pool:
> -	if (hostt->cmd_size)
> +	if (hostt->cmd_size) {
>   		scsi_free_host_cmd_pool(pool);
> +		hostt->cmd_pool = NULL;
> +	}
>   	goto out;
>   }
>
> @@ -447,8 +453,10 @@ static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
>   	if (!--pool->users) {
>   		kmem_cache_destroy(pool->cmd_slab);
>   		kmem_cache_destroy(pool->sense_slab);
> -		if (hostt->cmd_size)
> +		if (hostt->cmd_size) {
>   			scsi_free_host_cmd_pool(pool);
> +			hostt->cmd_pool = NULL;
> +		}
>   	}
>   	mutex_unlock(&host_cmd_pool_mutex);
>   }
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)