A set of IRDMA_CQP_SW_SQSIZE_2048 (i.e. 2048) 'cqp_request' are
pre-allocated and zeroed in 'irdma_create_cqp()' (hw.c). These
structures are managed with the 'cqp->cqp_avail_reqs' list which keeps
track of available entries.
In 'irdma_free_cqp_request()' (utils.c), when an entry is recycled and goes
back to the 'cqp_avail_reqs' list, some fields are reseted.
However, one of these fields, 'compl_info', is initialized within
'irdma_alloc_and_get_cqp_request()'.
Move the corresponding memset to 'irdma_free_cqp_request()' so that the
clean-up is done in only one place. This makes the logic more easy to
understand.
This also saves this memset in the case that the 'cqp_avail_reqs' list is
empty and a new 'cqp_request' structure must be allocated. This memset is
useless, because the structure is already kzalloc'ed.
Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/infiniband/hw/irdma/utils.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/irdma/utils.c b/drivers/infiniband/hw/irdma/utils.c
index 5bbe44e54f9a..66711024d38b 100644
--- a/drivers/infiniband/hw/irdma/utils.c
+++ b/drivers/infiniband/hw/irdma/utils.c
@@ -445,7 +445,6 @@ struct irdma_cqp_request *irdma_alloc_and_get_cqp_request(struct irdma_cqp *cqp,
cqp_request->waiting = wait;
refcount_set(&cqp_request->refcnt, 1);
- memset(&cqp_request->compl_info, 0, sizeof(cqp_request->compl_info));
return cqp_request;
}
@@ -475,6 +474,7 @@ void irdma_free_cqp_request(struct irdma_cqp *cqp,
cqp_request->request_done = false;
cqp_request->callback_fcn = NULL;
cqp_request->waiting = false;
+ memset(&cqp_request->compl_info, 0, sizeof(cqp_request->compl_info));
spin_lock_irqsave(&cqp->req_lock, flags);
list_add_tail(&cqp_request->list, &cqp->cqp_avail_reqs);
--
2.30.2
On Mon, Jul 19, 2021 at 07:02:15PM +0200, Christophe JAILLET wrote:
> A set of IRDMA_CQP_SW_SQSIZE_2048 (i.e. 2048) 'cqp_request' are
> pre-allocated and zeroed in 'irdma_create_cqp()' (hw.c). These
> structures are managed with the 'cqp->cqp_avail_reqs' list which keeps
> track of available entries.
>
> In 'irdma_free_cqp_request()' (utils.c), when an entry is recycled and goes
> back to the 'cqp_avail_reqs' list, some fields are reseted.
>
> However, one of these fields, 'compl_info', is initialized within
> 'irdma_alloc_and_get_cqp_request()'.
>
> Move the corresponding memset to 'irdma_free_cqp_request()' so that the
> clean-up is done in only one place. This makes the logic more easy to
> understand.
I'm not so sure. The function irdma_alloc_and_get_cqp_request() returns
prepared cqp_request and all users expect that it will returned cleaned
one. The reliance on some other place to clear part of the structure is
prone to errors.
Thanks
>
> This also saves this memset in the case that the 'cqp_avail_reqs' list is
> empty and a new 'cqp_request' structure must be allocated. This memset is
> useless, because the structure is already kzalloc'ed.
>
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> drivers/infiniband/hw/irdma/utils.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/infiniband/hw/irdma/utils.c b/drivers/infiniband/hw/irdma/utils.c
> index 5bbe44e54f9a..66711024d38b 100644
> --- a/drivers/infiniband/hw/irdma/utils.c
> +++ b/drivers/infiniband/hw/irdma/utils.c
> @@ -445,7 +445,6 @@ struct irdma_cqp_request *irdma_alloc_and_get_cqp_request(struct irdma_cqp *cqp,
>
> cqp_request->waiting = wait;
> refcount_set(&cqp_request->refcnt, 1);
> - memset(&cqp_request->compl_info, 0, sizeof(cqp_request->compl_info));
>
> return cqp_request;
> }
> @@ -475,6 +474,7 @@ void irdma_free_cqp_request(struct irdma_cqp *cqp,
> cqp_request->request_done = false;
> cqp_request->callback_fcn = NULL;
> cqp_request->waiting = false;
> + memset(&cqp_request->compl_info, 0, sizeof(cqp_request->compl_info));
>
> spin_lock_irqsave(&cqp->req_lock, flags);
> list_add_tail(&cqp_request->list, &cqp->cqp_avail_reqs);
> --
> 2.30.2
>
Le 20/07/2021 à 14:23, Leon Romanovsky a écrit :
> On Mon, Jul 19, 2021 at 07:02:15PM +0200, Christophe JAILLET wrote:
>> A set of IRDMA_CQP_SW_SQSIZE_2048 (i.e. 2048) 'cqp_request' are
>> pre-allocated and zeroed in 'irdma_create_cqp()' (hw.c). These
>> structures are managed with the 'cqp->cqp_avail_reqs' list which keeps
>> track of available entries.
>>
>> In 'irdma_free_cqp_request()' (utils.c), when an entry is recycled and goes
>> back to the 'cqp_avail_reqs' list, some fields are reseted.
>>
>> However, one of these fields, 'compl_info', is initialized within
>> 'irdma_alloc_and_get_cqp_request()'.
>>
>> Move the corresponding memset to 'irdma_free_cqp_request()' so that the
>> clean-up is done in only one place. This makes the logic more easy to
>> understand.
>
> I'm not so sure. The function irdma_alloc_and_get_cqp_request() returns
> prepared cqp_request and all users expect that it will returned cleaned
> one. The reliance on some other place to clear part of the structure is
> prone to errors.
Ok, so maybe, moving:
cqp_request->request_done = false;
cqp_request->callback_fcn = NULL;
cqp_request->waiting = false;
from 'irdma_free_cqp_request()' to 'irdma_alloc_and_get_cqp_request()'
to make explicit what is reseted makes more sense?
From my point of view, it is same same: all (re)initialization are done
at 1 place only.
This would also avoid setting 'waiting' twice (once to false in
'irdma_free_cqp_request()' and one to 'wait'
'irdma_alloc_and_get_cqp_request()')
CJ
>
> Thanks
>
>>
>> This also saves this memset in the case that the 'cqp_avail_reqs' list is
>> empty and a new 'cqp_request' structure must be allocated. This memset is
>> useless, because the structure is already kzalloc'ed.
>>
>> Signed-off-by: Christophe JAILLET <[email protected]>
>> ---
>> drivers/infiniband/hw/irdma/utils.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/hw/irdma/utils.c b/drivers/infiniband/hw/irdma/utils.c
>> index 5bbe44e54f9a..66711024d38b 100644
>> --- a/drivers/infiniband/hw/irdma/utils.c
>> +++ b/drivers/infiniband/hw/irdma/utils.c
>> @@ -445,7 +445,6 @@ struct irdma_cqp_request *irdma_alloc_and_get_cqp_request(struct irdma_cqp *cqp,
>>
>> cqp_request->waiting = wait;
>> refcount_set(&cqp_request->refcnt, 1);
>> - memset(&cqp_request->compl_info, 0, sizeof(cqp_request->compl_info));
>>
>> return cqp_request;
>> }
>> @@ -475,6 +474,7 @@ void irdma_free_cqp_request(struct irdma_cqp *cqp,
>> cqp_request->request_done = false;
>> cqp_request->callback_fcn = NULL;
>> cqp_request->waiting = false;
>> + memset(&cqp_request->compl_info, 0, sizeof(cqp_request->compl_info));
>>
>> spin_lock_irqsave(&cqp->req_lock, flags);
>> list_add_tail(&cqp_request->list, &cqp->cqp_avail_reqs);
>> --
>> 2.30.2
>>
>
On Tue, Jul 20, 2021 at 03:05:55PM +0200, Christophe JAILLET wrote:
> Le 20/07/2021 ? 14:23, Leon Romanovsky a ?crit?:
> > On Mon, Jul 19, 2021 at 07:02:15PM +0200, Christophe JAILLET wrote:
> > > A set of IRDMA_CQP_SW_SQSIZE_2048 (i.e. 2048) 'cqp_request' are
> > > pre-allocated and zeroed in 'irdma_create_cqp()' (hw.c). These
> > > structures are managed with the 'cqp->cqp_avail_reqs' list which keeps
> > > track of available entries.
> > >
> > > In 'irdma_free_cqp_request()' (utils.c), when an entry is recycled and goes
> > > back to the 'cqp_avail_reqs' list, some fields are reseted.
> > >
> > > However, one of these fields, 'compl_info', is initialized within
> > > 'irdma_alloc_and_get_cqp_request()'.
> > >
> > > Move the corresponding memset to 'irdma_free_cqp_request()' so that the
> > > clean-up is done in only one place. This makes the logic more easy to
> > > understand.
> >
> > I'm not so sure. The function irdma_alloc_and_get_cqp_request() returns
> > prepared cqp_request and all users expect that it will returned cleaned
> > one. The reliance on some other place to clear part of the structure is
> > prone to errors.
>
> Ok, so maybe, moving:
> cqp_request->request_done = false;
> cqp_request->callback_fcn = NULL;
> cqp_request->waiting = false;
> from 'irdma_free_cqp_request()' to 'irdma_alloc_and_get_cqp_request()' to
> make explicit what is reseted makes more sense?
I think so, but it requires double check that these cleared values are
not used after irdma_free_cqp_request().
This is another reason why clearing fields after _free_ routine is
mostly wrong. It hides errors when data is accessed after release.
Thanks