linux-kernel - [PATCH 05/10] Revert "iommu/amd: Avoid locking get_irq

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Date:   Fri, 16 Mar 2018 21:18:31 +0100
From:   Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To:     Joerg Roedel <joro@...tes.org>
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        tglx@...utronix.de,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Scott Wood <swood@...hat.com>
Subject: [PATCH 05/10] Revert "iommu/amd: Avoid locking get_irq_table() from atomic context"

This reverts commit df42a04b15f1 ("iommu/amd: Avoid locking
get_irq_table() from atomic context").
Its goal is to avoid a warning/bug on RT. While I generally support that
goal this change is colliding with larger rework which accomplishes the
same goal but different.

Cc: Scott Wood <swood@...hat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 drivers/iommu/amd_iommu.c | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 5191319d9f0a..30ad2a3fbe15 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3602,22 +3602,7 @@ static void set_dte_irq_entry(u16 devid, struct irq_remap_table *table)
 	amd_iommu_dev_table[devid].data[2] = dte;
 }
 
-static struct irq_remap_table *get_irq_table(u16 devid)
-{
-	struct irq_remap_table *table;
-
-	if (WARN_ONCE(!amd_iommu_rlookup_table[devid],
-		      "%s: no iommu for devid %x\n", __func__, devid))
-		return NULL;
-
-	table = irq_lookup_table[devid];
-	if (WARN_ONCE(!table, "%s: no table for devid %x\n", __func__, devid))
-		return NULL;
-
-	return table;
-}
-
-static struct irq_remap_table *alloc_irq_table(u16 devid, bool ioapic)
+static struct irq_remap_table *get_irq_table(u16 devid, bool ioapic)
 {
 	struct irq_remap_table *table = NULL;
 	struct amd_iommu *iommu;
@@ -3704,7 +3689,7 @@ static int alloc_irq_index(u16 devid, int count, bool align)
 	if (!iommu)
 		return -ENODEV;
 
-	table = alloc_irq_table(devid, false);
+	table = get_irq_table(devid, false);
 	if (!table)
 		return -ENODEV;
 
@@ -3755,7 +3740,7 @@ static int modify_irte_ga(u16 devid, int index, struct irte_ga *irte,
 	if (iommu == NULL)
 		return -EINVAL;
 
-	table = get_irq_table(devid);
+	table = get_irq_table(devid, false);
 	if (!table)
 		return -ENOMEM;
 
@@ -3788,7 +3773,7 @@ static int modify_irte(u16 devid, int index, union irte *irte)
 	if (iommu == NULL)
 		return -EINVAL;
 
-	table = get_irq_table(devid);
+	table = get_irq_table(devid, false);
 	if (!table)
 		return -ENOMEM;
 
@@ -3812,7 +3797,7 @@ static void free_irte(u16 devid, int index)
 	if (iommu == NULL)
 		return;
 
-	table = get_irq_table(devid);
+	table = get_irq_table(devid, false);
 	if (!table)
 		return;
 
@@ -4130,7 +4115,7 @@ static int irq_remapping_alloc(struct irq_domain *domain, unsigned int virq,
 		return ret;
 
 	if (info->type == X86_IRQ_ALLOC_TYPE_IOAPIC) {
-		if (alloc_irq_table(devid, true))
+		if (get_irq_table(devid, true))
 			index = info->ioapic_pin;
 		else
 			ret = -ENOMEM;
@@ -4413,7 +4398,7 @@ int amd_iommu_update_ga(int cpu, bool is_run, void *data)
 	if (!iommu)
 		return -ENODEV;
 
-	irt = get_irq_table(devid);
+	irt = get_irq_table(devid, false);
 	if (!irt)
 		return -ENODEV;
 
-- 
2.16.2