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Commit 46583e8c authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Joerg Roedel
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iommu/ipmmu-vmsa: Fix allocation in atomic context 



When attaching a device to an IOMMU group with
CONFIG_DEBUG_ATOMIC_SLEEP=y:

    BUG: sleeping function called from invalid context at mm/slab.h:421
    in_atomic(): 1, irqs_disabled(): 128, pid: 61, name: kworker/1:1
    ...
    Call trace:
     ...
     arm_lpae_alloc_pgtable+0x114/0x184
     arm_64_lpae_alloc_pgtable_s1+0x2c/0x128
     arm_32_lpae_alloc_pgtable_s1+0x40/0x6c
     alloc_io_pgtable_ops+0x60/0x88
     ipmmu_attach_device+0x140/0x334

ipmmu_attach_device() takes a spinlock, while arm_lpae_alloc_pgtable()
allocates memory using GFP_KERNEL.  Originally, the ipmmu-vmsa driver
had its own custom page table allocation implementation using
GFP_ATOMIC, hence the spinlock was fine.

Fix this by replacing the spinlock by a mutex, like the arm-smmu driver
does.

Fixes: f20ed39f ("iommu/ipmmu-vmsa: Use the ARM LPAE page table allocator")
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 2ae86955

drivers/iommu/ipmmu-vmsa.c

+4 −5
Original line number Diff line number Diff line
@@ -74,7 +74,7 @@ struct ipmmu_vmsa_domain { 
	struct io_pgtable_ops *iop;



	unsigned int context_id;

	spinlock_t lock;			/* Protects mappings */

	struct mutex mutex;			/* Protects mappings */

};



static struct ipmmu_vmsa_domain *to_vmsa_domain(struct iommu_domain *dom)
@@ -600,7 +600,7 @@ static struct iommu_domain *__ipmmu_domain_alloc(unsigned type) 
	if (!domain)

		return NULL;



	spin_lock_init(&domain->lock);

	mutex_init(&domain->mutex);



	return &domain->io_domain;

}
@@ -646,7 +646,6 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain, 
	struct iommu_fwspec *fwspec = dev->iommu_fwspec;

	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);

	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);

	unsigned long flags;

	unsigned int i;

	int ret = 0;
@@ -655,7 +654,7 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain, 
		return -ENXIO;

	}



	spin_lock_irqsave(&domain->lock, flags);

	mutex_lock(&domain->mutex);



	if (!domain->mmu) {

		/* The domain hasn't been used yet, initialize it. */
@@ -679,7 +678,7 @@ static int ipmmu_attach_device(struct iommu_domain *io_domain, 
	} else

		dev_info(dev, "Reusing IPMMU context %u\n", domain->context_id);



	spin_unlock_irqrestore(&domain->lock, flags);

	mutex_unlock(&domain->mutex);



	if (ret < 0)

		return ret;