linux-kernel - [PATCH 3/8] staging: tidspbridge - change mmufault tasklet to a workqueue

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Date:	Mon, 25 Oct 2010 19:51:41 -0500
From:	Fernando Guzman Lugo <x0095840@...com>
To:	<gregkh@...e.de>
Cc:	<felipe.contreras@...ia.com>, <Hiroshi.DOYU@...ia.com>,
	<linux-kernel@...r.kernel.org>, <andy.shevchenko@...il.com>,
	<linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	Fernando Guzman Lugo <x0095840@...com>
Subject: [PATCH 3/8] staging: tidspbridge - change mmufault tasklet to a workqueue

We don't need to manage the mmufault inside a tasklet
it is safer using a workqueue.

Signed-off-by: Fernando Guzman Lugo <x0095840@...com>
---
 drivers/staging/tidspbridge/core/dsp-mmu.c |   34 ++++++++++++++++++----------
 1 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/tidspbridge/core/dsp-mmu.c b/drivers/staging/tidspbridge/core/dsp-mmu.c
index 983c95a..6d7501a 100644
--- a/drivers/staging/tidspbridge/core/dsp-mmu.c
+++ b/drivers/staging/tidspbridge/core/dsp-mmu.c
@@ -28,7 +28,8 @@
 
 #define MMU_CNTL_TWL_EN		(1 << 2)
 
-static struct tasklet_struct mmu_tasklet;
+static struct workqueue_struct *mmu_wq;
+static struct work_struct fault_work;
 
 #ifdef CONFIG_TIDSPBRIDGE_BACKTRACE
 static void mmu_fault_print_stack(struct bridge_dev_context *dev_context)
@@ -37,7 +38,10 @@ static void mmu_fault_print_stack(struct bridge_dev_context *dev_context)
 	u32 fa, tmp;
 	struct iotlb_entry e;
 	struct iommu *mmu = dev_context->dsp_mmu;
-	dummy_addr = (void *)__get_free_page(GFP_ATOMIC);
+
+	dummy_addr = (void *)__get_free_page(GFP_KERNEL);
+	if (!dummy_addr)
+		return;
 
 	/*
 	 * Before acking the MMU fault, let's make sure MMU can only
@@ -76,19 +80,19 @@ static void mmu_fault_print_stack(struct bridge_dev_context *dev_context)
 #endif
 
 
-static void fault_tasklet(unsigned long data)
+static void mmu_fault_work(struct work_struct *work)
 {
-	struct iommu *mmu = (struct iommu *)data;
 	struct bridge_dev_context *dev_ctx;
 	struct deh_mgr *dm;
 	u32 fa;
+
 	dev_get_deh_mgr(dev_get_first(), &dm);
 	dev_get_bridge_context(dev_get_first(), &dev_ctx);
 
 	if (!dm || !dev_ctx)
 		return;
 
-	fa = iommu_read_reg(mmu, MMU_FAULT_AD);
+	fa = iommu_read_reg(dev_ctx->dsp_mmu, MMU_FAULT_AD);
 
 #ifdef CONFIG_TIDSPBRIDGE_BACKTRACE
 	print_dsp_trace_buffer(dev_ctx);
@@ -109,7 +113,8 @@ static int mmu_fault_callback(struct iommu *mmu)
 		return -EPERM;
 
 	iommu_write_reg(mmu, 0, MMU_IRQENABLE);
-	tasklet_schedule(&mmu_tasklet);
+	queue_work(mmu_wq, &fault_work);
+
 	return 0;
 }
 
@@ -126,10 +131,16 @@ struct iommu *dsp_mmu_init()
 
 	mmu = iommu_get("iva2");
 
-	if (!IS_ERR(mmu)) {
-		tasklet_init(&mmu_tasklet, fault_tasklet, (unsigned long)mmu);
-		mmu->isr = mmu_fault_callback;
+	if (IS_ERR(mmu))
+		return mmu;
+
+	mmu->isr = mmu_fault_callback;
+	mmu_wq = create_workqueue("dsp-mmu_wq");
+	if (!mmu_wq) {
+		iommu_put(mmu);
+		return ERR_PTR(-ENOMEM);
 	}
+	INIT_WORK(&fault_work, mmu_fault_work);
 
 	return mmu;
 }
@@ -143,9 +154,8 @@ struct iommu *dsp_mmu_init()
  */
 void dsp_mmu_exit(struct iommu *mmu)
 {
-	if (mmu)
-		iommu_put(mmu);
-	tasklet_kill(&mmu_tasklet);
+	iommu_put(mmu);
+	destroy_workqueue(mmu_wq);
 }
 
 /**
-- 
1.6.3.3

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