[PATCH] iommu/ipmmu-vmsa: Replace spinlock with mutex

[Laurent Pinchart]

The spinlock is used to protect domain initialization when attaching a
device, which allocates memory with GFP_KERNEL. Replace it with a mutex
as the initialization always runs in a sleepable context.

Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
---
 drivers/iommu/ipmmu-vmsa.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 1a67c531a07e..24a950091458 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/iommu.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/sizes.h>
@@ -44,7 +45,7 @@ struct ipmmu_vmsa_domain {
        struct io_pgtable_ops *iop;
 
        unsigned int context_id;
-       spinlock_t lock;                        /* Protects mappings */
+       struct mutex lock;                      /* Protects domain init */
 };
 
 struct ipmmu_vmsa_archdata {
@@ -473,7 +474,7 @@ static struct iommu_domain *ipmmu_domain_alloc(unsigned 
type)
        if (!domain)
                return NULL;
 
-       spin_lock_init(&domain->lock);
+       mutex_init(&domain->lock);
 
        return &domain->io_domain;
 }
@@ -488,6 +489,7 @@ static void ipmmu_domain_free(struct iommu_domain 
*io_domain)
         */
        ipmmu_domain_destroy_context(domain);
        free_io_pgtable_ops(domain->iop);
+       mutex_destroy(&domain->lock);
        kfree(domain);
 }
 
@@ -497,7 +499,6 @@ static int ipmmu_attach_device(struct iommu_domain 
*io_domain,
        struct ipmmu_vmsa_archdata *archdata = dev->archdata.iommu;
        struct ipmmu_vmsa_device *mmu = archdata->mmu;
        struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
-       unsigned long flags;
        unsigned int i;
        int ret = 0;
 
@@ -506,7 +507,7 @@ static int ipmmu_attach_device(struct iommu_domain 
*io_domain,
                return -ENXIO;
        }
 
-       spin_lock_irqsave(&domain->lock, flags);
+       mutex_lock(&domain->lock);
 
        if (!domain->mmu) {
                /* The domain hasn't been used yet, initialize it. */
@@ -522,7 +523,7 @@ static int ipmmu_attach_device(struct iommu_domain 
*io_domain,
                ret = -EINVAL;
        }
 
-       spin_unlock_irqrestore(&domain->lock, flags);
+       mutex_unlock(&domain->lock);
 
        if (ret < 0)
                return ret;
-- 
2.3.6

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