On 06/02/2024 11:01 am, John Garry wrote:
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@xxxxxxx>
Regardless of a couple of minor comments, below, FWIW:
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
Thanks!
---
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.
Oh, I never came across that before. On reflection, I am inclined to
think that the "iommu_" names are usefully informative to userspace, and
it's not worth churning the structure names themselves just to save a
couple of lines here.
+ 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".
That one I did consider, but since we now have just this one print and
no imminent reason to add more, I figured I'd just stick it inline, and
we can factor out a pr_fmt in future if we ever have cause to.
Cheers,
Robin.
+ 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);
