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Subject[PATCH/WIP/RFC 13/14] shmobile-ipmmu: Remove unneeded lock_add spinlock
Date
ipmmu_add_device() can never race with
shmobile_iommu_attach_all_devices(), called by ipmmu_iommu_init() as the
former is called from an arch initcall and the later from a subsys
initcall.

Remove the unneeded spinlock as well as the arm_iommu_attach_device() in
ipmmu_add_device(), as the condition that guards the call is always
false.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
---
drivers/iommu/shmobile-iommu.c | 18 +++---------------
1 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/shmobile-iommu.c b/drivers/iommu/shmobile-iommu.c
index bf1d0a4..2592d25 100644
--- a/drivers/iommu/shmobile-iommu.c
+++ b/drivers/iommu/shmobile-iommu.c
@@ -51,7 +51,6 @@ static struct dma_iommu_mapping *iommu_mapping;
static struct device *ipmmu_devices;
static struct dma_pool *l1pool, *l2pool;
static spinlock_t lock;
-static DEFINE_SPINLOCK(lock_add);
static struct shmobile_iommu_domain *attached;
static int num_attached_devices;

@@ -313,15 +312,12 @@ static struct iommu_ops shmobile_iommu_ops = {
static int shmobile_iommu_attach_all_devices(struct shmobile_ipmmu *ipmmu)
{
struct device *dev;
- int ret = 0;

- spin_lock(&lock_add);
iommu_mapping = arm_iommu_create_mapping(&platform_bus_type, 0x0,
L1_LEN << 20, 0);
- if (IS_ERR_OR_NULL(iommu_mapping)) {
- ret = PTR_ERR(iommu_mapping);
- goto err;
- }
+ if (IS_ERR_OR_NULL(iommu_mapping))
+ return PTR_ERR(iommu_mapping);
+
for (dev = ipmmu_devices; dev; ) {
struct shmobile_iommu_arch_data *data = dev->archdata.iommu;

@@ -332,8 +328,6 @@ static int shmobile_iommu_attach_all_devices(struct shmobile_ipmmu *ipmmu)

dev = data->next;
}
-err:
- spin_unlock(&lock_add);
return 0;
}

@@ -347,14 +341,8 @@ int ipmmu_add_device(struct device *dev)

dev->archdata.iommu = data;

- spin_lock(&lock_add);
data->next = ipmmu_devices;
ipmmu_devices = dev;
- if (!IS_ERR_OR_NULL(iommu_mapping)) {
- if (arm_iommu_attach_device(dev, iommu_mapping))
- pr_err("arm_iommu_attach_device failed\n");
- }
- spin_unlock(&lock_add);

return 0;
}
--
1.7.8.6


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