The function opencodes find_and_set_bit() with a for_each() loop. Fix
it, and make the whole function a simple almost one-liner.
Signed-off-by: Yury Norov <[email protected]>
---
net/smc/smc_wr.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 0021065a600a..b6f0cfc52788 100644
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -170,15 +170,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
{
- *idx = link->wr_tx_cnt;
if (!smc_link_sendable(link))
return -ENOLINK;
- for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
- if (!test_and_set_bit(*idx, link->wr_tx_mask))
- return 0;
- }
- *idx = link->wr_tx_cnt;
- return -EBUSY;
+
+ *idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
+ return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
}
/**
--
2.39.2
On 18.11.23 16:51, Yury Norov wrote:
> The function opencodes find_and_set_bit() with a for_each() loop. Fix
> it, and make the whole function a simple almost one-liner.
>
> Signed-off-by: Yury Norov <[email protected]>
> ---
> net/smc/smc_wr.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
> index 0021065a600a..b6f0cfc52788 100644
> --- a/net/smc/smc_wr.c
> +++ b/net/smc/smc_wr.c
> @@ -170,15 +170,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
>
> static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
> {
> - *idx = link->wr_tx_cnt;
> if (!smc_link_sendable(link))
> return -ENOLINK;
> - for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
> - if (!test_and_set_bit(*idx, link->wr_tx_mask))
> - return 0;
> - }
> - *idx = link->wr_tx_cnt;
> - return -EBUSY;
> +
> + *idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
> + return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
> }
>
> /**
My understanding is that you can omit the lines with
> - *idx = link->wr_tx_cnt;
because they only apply to the error paths and you checked that the calling function
does not use the idx variable in the error cases. Do I understand this correct?
If so the removal of these 2 lines is not related to your change of using find_and_set_bit(),
do I understand that correctly?
If so, it may be worth mentioning that in the commit message.
The prefix tag and subject imply that it is a bugfix. I think, first, it
should be a new feature with net-next tag. Also please use net/smc as
prefix.
Thanks,
Tony Lu
On Sat, Nov 18, 2023 at 07:51:00AM -0800, Yury Norov wrote:
> The function opencodes find_and_set_bit() with a for_each() loop. Fix
> it, and make the whole function a simple almost one-liner.
>
> Signed-off-by: Yury Norov <[email protected]>
> ---
> net/smc/smc_wr.c | 10 +++-------
> 1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
> index 0021065a600a..b6f0cfc52788 100644
> --- a/net/smc/smc_wr.c
> +++ b/net/smc/smc_wr.c
> @@ -170,15 +170,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
>
> static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
> {
> - *idx = link->wr_tx_cnt;
> if (!smc_link_sendable(link))
> return -ENOLINK;
> - for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
> - if (!test_and_set_bit(*idx, link->wr_tx_mask))
> - return 0;
> - }
> - *idx = link->wr_tx_cnt;
> - return -EBUSY;
> +
> + *idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
> + return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
> }
>
> /**
> --
> 2.39.2
On Mon, Nov 20, 2023 at 09:43:54AM +0100, Alexandra Winter wrote:
>
>
> On 18.11.23 16:51, Yury Norov wrote:
> > The function opencodes find_and_set_bit() with a for_each() loop. Fix
> > it, and make the whole function a simple almost one-liner.
> >
> > Signed-off-by: Yury Norov <[email protected]>
> > ---
> > net/smc/smc_wr.c | 10 +++-------
> > 1 file changed, 3 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
> > index 0021065a600a..b6f0cfc52788 100644
> > --- a/net/smc/smc_wr.c
> > +++ b/net/smc/smc_wr.c
> > @@ -170,15 +170,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
> >
> > static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
> > {
> > - *idx = link->wr_tx_cnt;
> > if (!smc_link_sendable(link))
> > return -ENOLINK;
> > - for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
> > - if (!test_and_set_bit(*idx, link->wr_tx_mask))
> > - return 0;
> > - }
> > - *idx = link->wr_tx_cnt;
> > - return -EBUSY;
> > +
> > + *idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
> > + return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
> > }
> >
> > /**
>
>
> My understanding is that you can omit the lines with
> > - *idx = link->wr_tx_cnt;
> because they only apply to the error paths and you checked that the calling function
> does not use the idx variable in the error cases. Do I understand this correct?
>
> If so the removal of these 2 lines is not related to your change of using find_and_set_bit(),
> do I understand that correctly?
>
> If so, it may be worth mentioning that in the commit message.
I'll add:
If find_and_set_bit() doesn't acquire a bit, it returns
->wr_tx_cnt, and so explicit initialization of *idx with
the same value is unneeded.
Makes sense?
On 21.11.23 14:41, Yury Norov wrote:
> On Mon, Nov 20, 2023 at 09:43:54AM +0100, Alexandra Winter wrote:
>>
>>
>> On 18.11.23 16:51, Yury Norov wrote:
>>> The function opencodes find_and_set_bit() with a for_each() loop. Fix
>>> it, and make the whole function a simple almost one-liner.
>>>
>>> Signed-off-by: Yury Norov <[email protected]>
>>> ---
>>> net/smc/smc_wr.c | 10 +++-------
>>> 1 file changed, 3 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
>>> index 0021065a600a..b6f0cfc52788 100644
>>> --- a/net/smc/smc_wr.c
>>> +++ b/net/smc/smc_wr.c
>>> @@ -170,15 +170,11 @@ void smc_wr_tx_cq_handler(struct ib_cq *ib_cq, void *cq_context)
>>>
>>> static inline int smc_wr_tx_get_free_slot_index(struct smc_link *link, u32 *idx)
>>> {
>>> - *idx = link->wr_tx_cnt;
>>> if (!smc_link_sendable(link))
>>> return -ENOLINK;
>>> - for_each_clear_bit(*idx, link->wr_tx_mask, link->wr_tx_cnt) {
>>> - if (!test_and_set_bit(*idx, link->wr_tx_mask))
>>> - return 0;
>>> - }
>>> - *idx = link->wr_tx_cnt;
>>> - return -EBUSY;
>>> +
>>> + *idx = find_and_set_bit(link->wr_tx_mask, link->wr_tx_cnt);
>>> + return *idx < link->wr_tx_cnt ? 0 : -EBUSY;
>>> }
>>>
>>> /**
>>
>>
>> My understanding is that you can omit the lines with
>>> - *idx = link->wr_tx_cnt;
>> because they only apply to the error paths and you checked that the calling function
>> does not use the idx variable in the error cases. Do I understand this correct?
>>
>> If so the removal of these 2 lines is not related to your change of using find_and_set_bit(),
>> do I understand that correctly?
>>
>> If so, it may be worth mentioning that in the commit message.
>
> I'll add:
>
> If find_and_set_bit() doesn't acquire a bit, it returns
> ->wr_tx_cnt, and so explicit initialization of *idx with
> the same value is unneeded.
>
> Makes sense?
>
Makes sense for the -EBUSY case, thank you.
It does not explain that you also removed the line for the -ENOLINK case
(which is ok, because the caller has also initialized it to link->wr_tx_cnt)