[v3,1/3] iommu/iova: Tidy up iova_cache_get() failure
Commit Message
Failure handling in iova_cache_get() is a little messy, and we'd like
to add some more to it, so let's tidy up a bit first. By leaving the
hotplug handler until last we can take advantage of kmem_cache_destroy()
being NULL-safe to have a single cleanup label. We can also improve the
error reporting, noting that kmem_cache_create() already screams if it
fails, so that one is redundant.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/iova.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)
Comments
On Mon, 5 Feb 2024, Robin Murphy wrote:
> Failure handling in iova_cache_get() is a little messy, and we'd like
> to add some more to it, so let's tidy up a bit first. By leaving the
> hotplug handler until last we can take advantage of kmem_cache_destroy()
> being NULL-safe to have a single cleanup label. We can also improve the
> error reporting, noting that kmem_cache_create() already screams if it
> fails, so that one is redundant.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Much easier to follow :)
Acked-by: David Rientjes <rientjes@google.com>
On 05/02/2024 15:32, Robin Murphy wrote:
> Failure handling in iova_cache_get() is a little messy, and we'd like
> to add some more to it, so let's tidy up a bit first. By leaving the
> hotplug handler until last we can take advantage of kmem_cache_destroy()
> being NULL-safe to have a single cleanup label. We can also improve the
> error reporting, noting that kmem_cache_create() already screams if it
> fails, so that one is redundant.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Regardless of a couple of minor comments, below, FWIW:
Reviewed-by: John Garry <john.g.garry@oracle.com>
> ---
> drivers/iommu/iova.c | 33 ++++++++++++++++-----------------
> 1 file changed, 16 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
> index d30e453d0fb4..cf95001d85c0 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -254,26 +254,20 @@ static void free_iova_mem(struct iova *iova)
>
> int iova_cache_get(void)
> {
> + int err = -ENOMEM;
> +
> mutex_lock(&iova_cache_mutex);
> if (!iova_cache_users) {
> - int ret;
> + iova_cache = kmem_cache_create("iommu_iova", sizeof(struct iova), 0,
> + SLAB_HWCACHE_ALIGN, NULL);
Maybe can use KMEM_CACHE(), but it would mean that the name would change.
> + if (!iova_cache)
> + goto out_err;
>
> - ret = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead", NULL,
> - iova_cpuhp_dead);
> - if (ret) {
> - mutex_unlock(&iova_cache_mutex);
> - pr_err("Couldn't register cpuhp handler\n");
> - return ret;
> - }
> -
> - iova_cache = kmem_cache_create(
> - "iommu_iova", sizeof(struct iova), 0,
> - SLAB_HWCACHE_ALIGN, NULL);
> - if (!iova_cache) {
> - cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
> - mutex_unlock(&iova_cache_mutex);
> - pr_err("Couldn't create iova cache\n");
> - return -ENOMEM;
> + err = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead",
> + NULL, iova_cpuhp_dead);
> + if (err) {
> + pr_err("IOVA: Couldn't register cpuhp handler: %pe\n", ERR_PTR(err));
Maybe can use pr_fmt with "iova".
> + goto out_err;
> }
> }
>
> @@ -281,6 +275,11 @@ int iova_cache_get(void)
> mutex_unlock(&iova_cache_mutex);
>
> return 0;
> +
> +out_err:
> + kmem_cache_destroy(iova_cache);
> + mutex_unlock(&iova_cache_mutex);
> + return err;
> }
> EXPORT_SYMBOL_GPL(iova_cache_get);
>
On Mon, Feb 05, 2024 at 03:32:39PM +0000, Robin Murphy wrote:
> Failure handling in iova_cache_get() is a little messy, and we'd like
> to add some more to it, so let's tidy up a bit first. By leaving the
> hotplug handler until last we can take advantage of kmem_cache_destroy()
> being NULL-safe to have a single cleanup label. We can also improve the
> error reporting, noting that kmem_cache_create() already screams if it
> fails, so that one is redundant.
>
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> drivers/iommu/iova.c | 33 ++++++++++++++++-----------------
> 1 file changed, 16 insertions(+), 17 deletions(-)
>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
@@ -254,26 +254,20 @@ static void free_iova_mem(struct iova *iova)
int iova_cache_get(void)
{
+ int err = -ENOMEM;
+
mutex_lock(&iova_cache_mutex);
if (!iova_cache_users) {
- int ret;
+ iova_cache = kmem_cache_create("iommu_iova", sizeof(struct iova), 0,
+ SLAB_HWCACHE_ALIGN, NULL);
+ if (!iova_cache)
+ goto out_err;
- ret = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead", NULL,
- iova_cpuhp_dead);
- if (ret) {
- mutex_unlock(&iova_cache_mutex);
- pr_err("Couldn't register cpuhp handler\n");
- return ret;
- }
-
- iova_cache = kmem_cache_create(
- "iommu_iova", sizeof(struct iova), 0,
- SLAB_HWCACHE_ALIGN, NULL);
- if (!iova_cache) {
- cpuhp_remove_multi_state(CPUHP_IOMMU_IOVA_DEAD);
- mutex_unlock(&iova_cache_mutex);
- pr_err("Couldn't create iova cache\n");
- return -ENOMEM;
+ err = cpuhp_setup_state_multi(CPUHP_IOMMU_IOVA_DEAD, "iommu/iova:dead",
+ NULL, iova_cpuhp_dead);
+ if (err) {
+ pr_err("IOVA: Couldn't register cpuhp handler: %pe\n", ERR_PTR(err));
+ goto out_err;
}
}
@@ -281,6 +275,11 @@ int iova_cache_get(void)
mutex_unlock(&iova_cache_mutex);
return 0;
+
+out_err:
+ kmem_cache_destroy(iova_cache);
+ mutex_unlock(&iova_cache_mutex);
+ return err;
}
EXPORT_SYMBOL_GPL(iova_cache_get);