In the old days, RDS used FMR (Fast Memory Registration) to register
IB MRs to be used by RDMA. A newer and better verbs based
registration/de-registration method called FRWR (Fast Registration
Work Request) was added to RDS by commit 1659185fb4d0 ("RDS: IB:
Support Fastreg MR (FRMR) memory registration mode") in 2016.

Detection and enablement of FRWR was done in commit 2cb2912d6563
("RDS: IB: add Fastreg MR (FRMR) detection support"). But said commit
added an extern bool prefer_frmr, which was not used by said commit -
nor used by later commits. Hence, remove it.

Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>

---

	v2 -> v3:
	      * As per Jakub's request, removed Cc: and Fixes: tags
	      * Subject to net-next (instead of net)

	v1 -> v2:
	      * Added commit message
	      * Added Cc: stable@vger.kernel.org
---
 net/rds/ib_mr.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/rds/ib_mr.h b/net/rds/ib_mr.h
index ea5e9aee4959e..5884de8c6f45b 100644
--- a/net/rds/ib_mr.h
+++ b/net/rds/ib_mr.h
@@ -108,7 +108,6 @@ struct rds_ib_mr_pool {
 };
 
 extern struct workqueue_struct *rds_ib_mr_wq;
-extern bool prefer_frmr;
 
 struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_dev,
 					     int npages);
-- 
2.43.5

On Thu, 2025-09-04 at 17:01 +0200, Håkon Bugge wrote:
> In the old days, RDS used FMR (Fast Memory Registration) to register
> IB MRs to be used by RDMA. A newer and better verbs based
> registration/de-registration method called FRWR (Fast Registration
> Work Request) was added to RDS by commit 1659185fb4d0 ("RDS: IB:
> Support Fastreg MR (FRMR) memory registration mode") in 2016.
> 
> Detection and enablement of FRWR was done in commit 2cb2912d6563
> ("RDS: IB: add Fastreg MR (FRMR) detection support"). But said commit
> added an extern bool prefer_frmr, which was not used by said commit -
> nor used by later commits. Hence, remove it.
> 
> Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
> 
> ---
Hi Håkon,

Just one nit with the change log indentation here.  Version numbering is typically left-aligned, unless you meant to
have a header of sorts to justify the level indentation.  Otherwise just bring the v2 -> v3: / v1 -> v2: lines flush
left.

Content-wise this patch looks fine to me.  With the indent nit fixed, you can add my rvb:
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>

Thank you!

Allison

> 
> 	v2 -> v3:
> 	      * As per Jakub's request, removed Cc: and Fixes: tags
> 	      * Subject to net-next (instead of net)
> 
> 	v1 -> v2:
> 	      * Added commit message
> 	      * Added Cc: stable@vger.kernel.org
> ---
>  net/rds/ib_mr.h | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/net/rds/ib_mr.h b/net/rds/ib_mr.h
> index ea5e9aee4959e..5884de8c6f45b 100644
> --- a/net/rds/ib_mr.h
> +++ b/net/rds/ib_mr.h
> @@ -108,7 +108,6 @@ struct rds_ib_mr_pool {
>  };
>  
>  extern struct workqueue_struct *rds_ib_mr_wq;
> -extern bool prefer_frmr;
>  
>  struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_dev,
>  					     int npages);

> On 5 Sep 2025, at 00:43, Allison Henderson <allison.henderson@oracle.com> wrote:
> 
> On Thu, 2025-09-04 at 17:01 +0200, Håkon Bugge wrote:
>> In the old days, RDS used FMR (Fast Memory Registration) to register
>> IB MRs to be used by RDMA. A newer and better verbs based
>> registration/de-registration method called FRWR (Fast Registration
>> Work Request) was added to RDS by commit 1659185fb4d0 ("RDS: IB:
>> Support Fastreg MR (FRMR) memory registration mode") in 2016.
>> 
>> Detection and enablement of FRWR was done in commit 2cb2912d6563
>> ("RDS: IB: add Fastreg MR (FRMR) detection support"). But said commit
>> added an extern bool prefer_frmr, which was not used by said commit -
>> nor used by later commits. Hence, remove it.
>> 
>> Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com>
>> 
>> ---
> Hi Håkon,
> 
> Just one nit with the change log indentation here.  Version numbering is typically left-aligned, unless you meant to
> have a header of sorts to justify the level indentation.  Otherwise just bring the v2 -> v3: / v1 -> v2: lines flush
> left.
> 
> Content-wise this patch looks fine to me.  With the indent nit fixed, you can add my rvb:
> Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Hi Allison,


Will do. But, as you know, what comes after the "---" line gets stripped off when the patch is applied anyway.


Thxs, Håkon

> 
> Thank you!
> 
> Allison
> 
>> 
>> v2 -> v3:
>>      * As per Jakub's request, removed Cc: and Fixes: tags
>>      * Subject to net-next (instead of net)
>> 
>> v1 -> v2:
>>      * Added commit message
>>      * Added Cc: stable@vger.kernel.org
>> ---
>> net/rds/ib_mr.h | 1 -
>> 1 file changed, 1 deletion(-)
>> 
>> diff --git a/net/rds/ib_mr.h b/net/rds/ib_mr.h
>> index ea5e9aee4959e..5884de8c6f45b 100644
>> --- a/net/rds/ib_mr.h
>> +++ b/net/rds/ib_mr.h
>> @@ -108,7 +108,6 @@ struct rds_ib_mr_pool {
>> };
>> 
>> extern struct workqueue_struct *rds_ib_mr_wq;
>> -extern bool prefer_frmr;
>> 
>> struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_dev,
>>     int npages);