releases/4.14.71/iommu-ipmmu-vmsa-fix-allocation-in-atomic-context.patch

From foo@baz Mon Sep 17 12:33:31 CEST 2018
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Fri, 20 Jul 2018 18:16:59 +0200
Subject: iommu/ipmmu-vmsa: Fix allocation in atomic context

From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit 46583e8c48c5a094ba28060615b3a7c8c576690f ]

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: f20ed39f53145e45 ("iommu/ipmmu-vmsa: Use the ARM LPAE page table allocator")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/iommu/ipmmu-vmsa.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -54,7 +54,7 @@ struct ipmmu_vmsa_domain {
 	struct io_pgtable_ops *iop;
 
 	unsigned int context_id;
-	spinlock_t lock;			/* Protects mappings */
+	struct mutex mutex;			/* Protects mappings */
 };
 
 struct ipmmu_vmsa_iommu_priv {
@@ -523,7 +523,7 @@ static struct iommu_domain *__ipmmu_doma
 	if (!domain)
 		return NULL;
 
-	spin_lock_init(&domain->lock);
+	mutex_init(&domain->mutex);
 
 	return &domain->io_domain;
 }
@@ -548,7 +548,6 @@ static int ipmmu_attach_device(struct io
 	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
 	struct ipmmu_vmsa_device *mmu = priv->mmu;
 	struct ipmmu_vmsa_domain *domain = to_vmsa_domain(io_domain);
-	unsigned long flags;
 	unsigned int i;
 	int ret = 0;
 
@@ -557,7 +556,7 @@ static int ipmmu_attach_device(struct io
 		return -ENXIO;
 	}
 
-	spin_lock_irqsave(&domain->lock, flags);
+	mutex_lock(&domain->mutex);
 
 	if (!domain->mmu) {
 		/* The domain hasn't been used yet, initialize it. */
@@ -574,7 +573,7 @@ static int ipmmu_attach_device(struct io
 	} 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;