[PATCH] iommu: simplify and fix ida handling

[PATCH] iommu: simplify and fix ida handling

[Heiner Kallweit]

Ida handling can be much simplified by using the ida_simple_.. functions.

This change also fixes the bug that previously checking for errors
returned by ida_get_new() was incomplete.
ida_get_new() can return errors other than EAGAIN, e.g. ENOSPC.
This case wasn't handled.

Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/iommu/iommu.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index debce45..4d3c4a8 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -35,7 +35,6 @@
 
 static struct kset *iommu_group_kset;
 static DEFINE_IDA(iommu_group_ida);
-static DEFINE_MUTEX(iommu_group_mutex);
 
 struct iommu_callback_data {
 	const struct iommu_ops *ops;
@@ -144,9 +143,7 @@ static void iommu_group_release(struct kobject *kobj)
 	if (group->iommu_data_release)
 		group->iommu_data_release(group->iommu_data);
 
-	mutex_lock(&iommu_group_mutex);
-	ida_remove(&iommu_group_ida, group->id);
-	mutex_unlock(&iommu_group_mutex);
+	ida_simple_remove(&iommu_group_ida, group->id);
 
 	if (group->default_domain)
 		iommu_domain_free(group->default_domain);
@@ -186,26 +183,17 @@ struct iommu_group *iommu_group_alloc(void)
 	INIT_LIST_HEAD(&group->devices);
 	BLOCKING_INIT_NOTIFIER_HEAD(&group->notifier);
 
-	mutex_lock(&iommu_group_mutex);
-
-again:
-	if (unlikely(0 == ida_pre_get(&iommu_group_ida, GFP_KERNEL))) {
+	ret = ida_simple_get(&iommu_group_ida, 0, 0, GFP_KERNEL);
+	if (ret < 0) {
 		kfree(group);
-		mutex_unlock(&iommu_group_mutex);
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(ret);
 	}
-
-	if (-EAGAIN == ida_get_new(&iommu_group_ida, &group->id))
-		goto again;
-
-	mutex_unlock(&iommu_group_mutex);
+	group->id = ret;
 
 	ret = kobject_init_and_add(&group->kobj, &iommu_group_ktype,
 				   NULL, "%d", group->id);
 	if (ret) {
-		mutex_lock(&iommu_group_mutex);
-		ida_remove(&iommu_group_ida, group->id);
-		mutex_unlock(&iommu_group_mutex);
+		ida_simple_remove(&iommu_group_ida, group->id);
 		kfree(group);
 		return ERR_PTR(ret);
 	}
-- 
2.9.0

Re: [PATCH] iommu: simplify and fix ida handling

[Joerg Roedel]

On Wed, Jun 29, 2016 at 09:13:59PM +0200, Heiner Kallweit wrote:
> Ida handling can be much simplified by using the ida_simple_.. functions.
> 
> This change also fixes the bug that previously checking for errors
> returned by ida_get_new() was incomplete.
> ida_get_new() can return errors other than EAGAIN, e.g. ENOSPC.
> This case wasn't handled.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/iommu/iommu.c | 24 ++++++------------------
>  1 file changed, 6 insertions(+), 18 deletions(-)

The patch does not apply. Please rebase it against the latest upstream
kernel and resend.

Re: [PATCH] iommu: simplify and fix ida handling

[Heiner Kallweit]

Am 04.07.2016 um 13:46 schrieb Joerg Roedel:
> On Wed, Jun 29, 2016 at 09:13:59PM +0200, Heiner Kallweit wrote:
>> Ida handling can be much simplified by using the ida_simple_.. functions.
>>
>> This change also fixes the bug that previously checking for errors
>> returned by ida_get_new() was incomplete.
>> ida_get_new() can return errors other than EAGAIN, e.g. ENOSPC.
>> This case wasn't handled.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>> ---
>>  drivers/iommu/iommu.c | 24 ++++++------------------
>>  1 file changed, 6 insertions(+), 18 deletions(-)
> 
> The patch does not apply. Please rebase it against the latest upstream
> kernel and resend.
> 
This patch applies on top of patch "[PATCH 1/3] iommu: simplify init function"
I submitted on June 28th. Do you have an opinion on that patch?

Regards, Heiner

Re: [PATCH] iommu: simplify and fix ida handling

[Joerg Roedel]

On Mon, Jul 04, 2016 at 09:01:18PM +0200, Heiner Kallweit wrote:
> Am 04.07.2016 um 13:46 schrieb Joerg Roedel:
> > On Wed, Jun 29, 2016 at 09:13:59PM +0200, Heiner Kallweit wrote:
> >> Ida handling can be much simplified by using the ida_simple_.. functions.
> >>
> >> This change also fixes the bug that previously checking for errors
> >> returned by ida_get_new() was incomplete.
> >> ida_get_new() can return errors other than EAGAIN, e.g. ENOSPC.
> >> This case wasn't handled.
> >>
> >> Signed-off-by: Heiner Kallweit <hkallweit1-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> >> ---
> >>  drivers/iommu/iommu.c | 24 ++++++------------------
> >>  1 file changed, 6 insertions(+), 18 deletions(-)
> > 
> > The patch does not apply. Please rebase it against the latest upstream
> > kernel and resend.
> > 
> This patch applies on top of patch "[PATCH 1/3] iommu: simplify init function"
> I submitted on June 28th. Do you have an opinion on that patch?

Applied both, thanks.