2024-03-11 09:21:24

by Kory Maincent

Subject: [PATCH v2 net-next] ptp: Move from simple ida to xarray

Move from simple ida to xarray for storing and loading the ptp_clock
pointer. This prepares support for future hardware timestamp selection by
being able to link the ptp clock index to its pointer.

Signed-off-by: Kory Maincent <[email protected]>
---

Change in v2:
- Update an err value missing
---
drivers/ptp/ptp_clock.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 3aaf1a3430c5..9339fd475df0 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -31,7 +31,7 @@ struct class *ptp_class;

static dev_t ptp_devt;

-static DEFINE_IDA(ptp_clocks_map);
+static DEFINE_XARRAY_ALLOC(ptp_clocks_map);

/* time stamp event queue operations */

@@ -201,7 +201,7 @@ static void ptp_clock_release(struct device *dev)
bitmap_free(tsevq->mask);
kfree(tsevq);
debugfs_remove(ptp->debugfs_root);
- ida_free(&ptp_clocks_map, ptp->index);
+ xa_erase(&ptp_clocks_map, ptp->index);
kfree(ptp);
}

@@ -246,12 +246,12 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
if (ptp == NULL)
goto no_memory;

- index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
- if (index < 0) {
- err = index;
+ err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
+ GFP_KERNEL);
+ if (err)
goto no_slot;
- }

+ err = -ENOMEM;
ptp->clock.ops = ptp_clock_ops;
ptp->info = info;
ptp->devid = MKDEV(major, index);
@@ -378,7 +378,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
list_del(&queue->qlist);
kfree(queue);
no_memory_queue:
- ida_free(&ptp_clocks_map, index);
+ xa_erase(&ptp_clocks_map, index);
no_slot:
kfree(ptp);
no_memory:
@@ -511,7 +511,7 @@ static void __exit ptp_exit(void)
{
class_destroy(ptp_class);
unregister_chrdev_region(ptp_devt, MINORMASK + 1);
- ida_destroy(&ptp_clocks_map);
+ xa_destroy(&ptp_clocks_map);
}

static int __init ptp_init(void)
--
2.25.1

2024-03-11 13:42:46

by Przemek Kitszel

Subject: Re: [PATCH v2 net-next] ptp: Move from simple ida to xarray

On 3/11/24 10:21, Kory Maincent wrote:
> Move from simple ida to xarray for storing and loading the ptp_clock
> pointer. This prepares support for future hardware timestamp selection by
> being able to link the ptp clock index to its pointer.
>
> Signed-off-by: Kory Maincent <[email protected]>
> ---
>
> Change in v2:
> - Update an err value missing
> ---
> drivers/ptp/ptp_clock.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
> index 3aaf1a3430c5..9339fd475df0 100644
> --- a/drivers/ptp/ptp_clock.c
> +++ b/drivers/ptp/ptp_clock.c
> @@ -31,7 +31,7 @@ struct class *ptp_class;
>
> static dev_t ptp_devt;
>
> -static DEFINE_IDA(ptp_clocks_map);
> +static DEFINE_XARRAY_ALLOC(ptp_clocks_map);
>
> /* time stamp event queue operations */
>
> @@ -201,7 +201,7 @@ static void ptp_clock_release(struct device *dev)
> bitmap_free(tsevq->mask);
> kfree(tsevq);
> debugfs_remove(ptp->debugfs_root);
> - ida_free(&ptp_clocks_map, ptp->index);
> + xa_erase(&ptp_clocks_map, ptp->index);
> kfree(ptp);
> }
>
> @@ -246,12 +246,12 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
> if (ptp == NULL)
> goto no_memory;
>
> - index = ida_alloc_max(&ptp_clocks_map, MINORMASK, GFP_KERNEL);
> - if (index < 0) {
> - err = index;
> + err = xa_alloc(&ptp_clocks_map, &index, ptp, xa_limit_31b,
> + GFP_KERNEL);
> + if (err)
> goto no_slot;
> - }
>
> + err = -ENOMEM;

here it looks weird (even if technically correct),
I would either move the err assignement down, just above next kzalloc()
call, or refactor function to use the following idiom:
ptr = kzalloc(...)
if (!ptr) {
err = -ENOMEM;
goto somewhere;
}

(it's already is for @vclock_index field init)

Otherwise context is too small to tell what is the reason.

> ptp->clock.ops = ptp_clock_ops;
> ptp->info = info;
> ptp->devid = MKDEV(major, index);
> @@ -378,7 +378,7 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
> list_del(&queue->qlist);
> kfree(queue);
> no_memory_queue:
> - ida_free(&ptp_clocks_map, index);
> + xa_erase(&ptp_clocks_map, index);
> no_slot:
> kfree(ptp);
> no_memory:
> @@ -511,7 +511,7 @@ static void __exit ptp_exit(void)
> {
> class_destroy(ptp_class);
> unregister_chrdev_region(ptp_devt, MINORMASK + 1);
> - ida_destroy(&ptp_clocks_map);
> + xa_destroy(&ptp_clocks_map);
> }
>
> static int __init ptp_init(void)