misc: mic: add threaded irq support in host driver

Convert mic_request_irq to mic_request_threaded_irq to support threaded
irq for virtual devices on mic bus.

Reviewed-by: Ashutosh Dixit <[e-mail]>
Reviewed-by: Nikhil Rao <[e-mail]>
Reviewed-by: Sudeep Dutt <[e-mail]>
Signed-off-by: Siva Yerramreddy <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/mic/host/mic_intr.c

···
 #include "../common/mic_dev.h"
 #include "mic_device.h"
 
-/*
- * mic_invoke_callback - Invoke callback functions registered for
- * the corresponding source id.
- *
- * @mdev: pointer to the mic_device instance
- * @idx: The interrupt source id.
- *
- * Returns none.
- */
-static inline void mic_invoke_callback(struct mic_device *mdev, int idx)
+static irqreturn_t mic_thread_fn(int irq, void *dev)
 {
+	struct mic_device *mdev = dev;
+	struct mic_intr_info *intr_info = mdev->intr_info;
+	struct mic_irq_info *irq_info = &mdev->irq_info;
 	struct mic_intr_cb *intr_cb;
 	struct pci_dev *pdev = container_of(mdev->sdev->parent,
-		struct pci_dev, dev);
+					    struct pci_dev, dev);
+	int i;
 
-	spin_lock(&mdev->irq_info.mic_intr_lock);
-	list_for_each_entry(intr_cb, &mdev->irq_info.cb_list[idx], list)
-		if (intr_cb->func)
-			intr_cb->func(pdev->irq, intr_cb->data);
-	spin_unlock(&mdev->irq_info.mic_intr_lock);
+	spin_lock(&irq_info->mic_thread_lock);
+	for (i = intr_info->intr_start_idx[MIC_INTR_DB];
+			i < intr_info->intr_len[MIC_INTR_DB]; i++)
+		if (test_and_clear_bit(i, &irq_info->mask)) {
+			list_for_each_entry(intr_cb, &irq_info->cb_list[i],
+					    list)
+				if (intr_cb->thread_fn)
+					intr_cb->thread_fn(pdev->irq,
+							 intr_cb->data);
+		}
+	spin_unlock(&irq_info->mic_thread_lock);
+	return IRQ_HANDLED;
 }
-
 /**
  * mic_interrupt - Generic interrupt handler for
  * MSI and INTx based interrupts.
···
 static irqreturn_t mic_interrupt(int irq, void *dev)
 {
 	struct mic_device *mdev = dev;
-	struct mic_intr_info *info = mdev->intr_info;
+	struct mic_intr_info *intr_info = mdev->intr_info;
+	struct mic_irq_info *irq_info = &mdev->irq_info;
+	struct mic_intr_cb *intr_cb;
+	struct pci_dev *pdev = container_of(mdev->sdev->parent,
+					    struct pci_dev, dev);
 	u32 mask;
 	int i;
 
···
 	if (!mask)
 		return IRQ_NONE;
 
-	for (i = info->intr_start_idx[MIC_INTR_DB];
-			i < info->intr_len[MIC_INTR_DB]; i++)
-		if (mask & BIT(i))
-			mic_invoke_callback(mdev, i);
-
-	return IRQ_HANDLED;
+	spin_lock(&irq_info->mic_intr_lock);
+	for (i = intr_info->intr_start_idx[MIC_INTR_DB];
+			i < intr_info->intr_len[MIC_INTR_DB]; i++)
+		if (mask & BIT(i)) {
+			list_for_each_entry(intr_cb, &irq_info->cb_list[i],
+					    list)
+				if (intr_cb->handler)
+					intr_cb->handler(pdev->irq,
+							 intr_cb->data);
+			set_bit(i, &irq_info->mask);
+		}
+	spin_unlock(&irq_info->mic_intr_lock);
+	return IRQ_WAKE_THREAD;
 }
 
 /* Return the interrupt offset from the index. Index is 0 based. */
···
  *
  * @mdev: pointer to the mic_device instance
  * @idx: The source id to be registered.
- * @func: The function to be called when the source id receives
+ * @handler: The function to be called when the source id receives
  * the interrupt.
+ * @thread_fn: thread fn. corresponding to the handler
  * @data: Private data of the requester.
  * Return the callback structure that was registered or an
  * appropriate error on failure.
  */
 static struct mic_intr_cb *mic_register_intr_callback(struct mic_device *mdev,
-			u8 idx, irqreturn_t (*func) (int irq, void *dev),
+			u8 idx, irq_handler_t handler, irq_handler_t thread_fn,
 			void *data)
 {
 	struct mic_intr_cb *intr_cb;
···
 	if (!intr_cb)
 		return ERR_PTR(-ENOMEM);
 
-	intr_cb->func = func;
+	intr_cb->handler = handler;
+	intr_cb->thread_fn = thread_fn;
 	intr_cb->data = data;
 	intr_cb->cb_id = ida_simple_get(&mdev->irq_info.cb_ida,
 		0, 0, GFP_KERNEL);
···
 		goto ida_fail;
 	}
 
+	spin_lock(&mdev->irq_info.mic_thread_lock);
 	spin_lock_irqsave(&mdev->irq_info.mic_intr_lock, flags);
 	list_add_tail(&intr_cb->list, &mdev->irq_info.cb_list[idx]);
 	spin_unlock_irqrestore(&mdev->irq_info.mic_intr_lock, flags);
+	spin_unlock(&mdev->irq_info.mic_thread_lock);
 
 	return intr_cb;
 ida_fail:
···
 	unsigned long flags;
 	int i;
 
+	spin_lock(&mdev->irq_info.mic_thread_lock);
+	spin_lock_irqsave(&mdev->irq_info.mic_intr_lock, flags);
 	for (i = 0;  i < MIC_NUM_OFFSETS; i++) {
-		spin_lock_irqsave(&mdev->irq_info.mic_intr_lock, flags);
 		list_for_each_safe(pos, tmp, &mdev->irq_info.cb_list[i]) {
 			intr_cb = list_entry(pos, struct mic_intr_cb, list);
 			if (intr_cb->cb_id == idx) {
···
 				kfree(intr_cb);
 				spin_unlock_irqrestore(
 					&mdev->irq_info.mic_intr_lock, flags);
+				spin_unlock(&mdev->irq_info.mic_thread_lock);
 				return i;
 			}
 		}
-		spin_unlock_irqrestore(&mdev->irq_info.mic_intr_lock, flags);
 	}
+	spin_unlock_irqrestore(&mdev->irq_info.mic_intr_lock, flags);
+	spin_unlock(&mdev->irq_info.mic_thread_lock);
 	return MIC_NUM_OFFSETS;
 }
 
···
 		INIT_LIST_HEAD(&mdev->irq_info.cb_list[i]);
 	ida_init(&mdev->irq_info.cb_ida);
 	spin_lock_init(&mdev->irq_info.mic_intr_lock);
+	spin_lock_init(&mdev->irq_info.mic_thread_lock);
 	return 0;
 }
 
···
 	struct mic_intr_cb *intr_cb;
 	int i;
 
+	spin_lock(&mdev->irq_info.mic_thread_lock);
+	spin_lock_irqsave(&mdev->irq_info.mic_intr_lock, flags);
 	for (i = 0; i < MIC_NUM_OFFSETS; i++) {
-		spin_lock_irqsave(&mdev->irq_info.mic_intr_lock, flags);
 
-		if (list_empty(&mdev->irq_info.cb_list[i])) {
-			spin_unlock_irqrestore(&mdev->irq_info.mic_intr_lock,
-					       flags);
+		if (list_empty(&mdev->irq_info.cb_list[i]))
 			break;
-		}
 
 		list_for_each_safe(pos, tmp, &mdev->irq_info.cb_list[i]) {
 			intr_cb = list_entry(pos, struct mic_intr_cb, list);
···
 					  intr_cb->cb_id);
 			kfree(intr_cb);
 		}
-		spin_unlock_irqrestore(&mdev->irq_info.mic_intr_lock, flags);
 	}
+	spin_unlock_irqrestore(&mdev->irq_info.mic_intr_lock, flags);
+	spin_unlock(&mdev->irq_info.mic_thread_lock);
 	ida_destroy(&mdev->irq_info.cb_ida);
 	kfree(mdev->irq_info.cb_list);
 }
···
 		goto err_nomem2;
 	}
 
-	rc = request_irq(pdev->irq, mic_interrupt, 0 , "mic-msi", mdev);
+	rc = request_threaded_irq(pdev->irq, mic_interrupt, mic_thread_fn,
+				  0, "mic-msi", mdev);
 	if (rc) {
 		dev_err(&pdev->dev, "Error allocating MSI interrupt\n");
 		goto err_irq_req_fail;
···
 		goto err_nomem;
 	}
 
-	rc = request_irq(pdev->irq, mic_interrupt,
-		IRQF_SHARED, "mic-intx", mdev);
+	rc = request_threaded_irq(pdev->irq, mic_interrupt, mic_thread_fn,
+				  IRQF_SHARED, "mic-intx", mdev);
 	if (rc)
 		goto err;
 
···
 #define MK_COOKIE(x, y) ((x) | (y) << COOKIE_ID_SHIFT)
 
 /**
- * mic_request_irq - request an irq. mic_mutex needs
+ * mic_request_threaded_irq - request an irq. mic_mutex needs
  * to be held before calling this function.
  *
  * @mdev: pointer to mic_device instance
- * @func: The callback function that handles the interrupt.
+ * @handler: The callback function that handles the interrupt.
  * The function needs to call ack_interrupts
  * (mdev->ops->ack_interrupt(mdev)) when handling the interrupts.
+ * @thread_fn: thread fn required by request_threaded_irq.
  * @name: The ASCII name of the callee requesting the irq.
  * @data: private data that is returned back when calling the
  * function handler.
···
  * error code.
  *
  */
-struct mic_irq *mic_request_irq(struct mic_device *mdev,
-	irqreturn_t (*func)(int irq, void *dev),
-	const char *name, void *data, int intr_src,
-	enum mic_intr_type type)
+struct mic_irq *
+mic_request_threaded_irq(struct mic_device *mdev,
+			 irq_handler_t handler, irq_handler_t thread_fn,
+			 const char *name, void *data, int intr_src,
+			 enum mic_intr_type type)
 {
 	u16 offset;
 	int rc = 0;
···
 			goto err;
 		}
 
-		rc = request_irq(msix->vector, func, 0, name, data);
+		rc = request_threaded_irq(msix->vector, handler, thread_fn,
+					  0, name, data);
 		if (rc) {
 			dev_dbg(mdev->sdev->parent,
 				"request irq failed rc = %d\n", rc);
···
 		dev_dbg(mdev->sdev->parent, "irq: %d assigned for src: %d\n",
 			msix->vector, intr_src);
 	} else {
-		intr_cb = mic_register_intr_callback(mdev,
-				offset, func, data);
+		intr_cb = mic_register_intr_callback(mdev, offset, handler,
+						     thread_fn, data);
 		if (IS_ERR(intr_cb)) {
 			dev_err(mdev->sdev->parent,
 				"No available callback entries for use\n");
···
  *  needs to be held before calling this function.
  *
  * @mdev: pointer to mic_device instance
- * @cookie: cookie obtained during a successful call to mic_request_irq
+ * @cookie: cookie obtained during a successful call to mic_request_threaded_irq
  * @data: private data specified by the calling function during the
- * mic_request_irq
+ * mic_request_threaded_irq
  *
  * returns: none.
  */

drivers/misc/mic/host/mic_intr.h

···
 #ifndef _MIC_INTR_H_
 #define _MIC_INTR_H_
 
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
 /*
  * The minimum number of msix vectors required for normal operation.
  * 3 for virtio network, console and block devices.
···
  * @num_vectors: The number of MSI/MSI-x vectors that have been allocated.
  * @cb_ida: callback ID allocator to track the callbacks registered.
  * @mic_intr_lock: spinlock to protect the interrupt callback list.
+ * @mic_thread_lock: spinlock to protect the thread callback list.
+ *		   This lock is used to protect against thread_fn while
+ *		   mic_intr_lock is used to protect against interrupt handler.
  * @cb_list: Array of callback lists one for each source.
+ * @mask: Mask used by the main thread fn to call the underlying thread fns.
  */
 struct mic_irq_info {
 	int next_avail_src;
···
 	u16 num_vectors;
 	struct ida cb_ida;
 	spinlock_t mic_intr_lock;
+	spinlock_t mic_thread_lock;
 	struct list_head *cb_list;
+	unsigned long mask;
 };
 
 /**
  * struct mic_intr_cb - Interrupt callback structure.
  *
- * @func: The callback function
+ * @handler: The callback function
+ * @thread_fn: The thread_fn.
  * @data: Private data of the requester.
  * @cb_id: The callback id. Identifies this callback.
  * @list: list head pointing to the next callback structure.
  */
 struct mic_intr_cb {
-	irqreturn_t (*func) (int irq, void *data);
+	irq_handler_t handler;
+	irq_handler_t thread_fn;
 	void *data;
 	int cb_id;
 	struct list_head list;
···
 };
 
 int mic_next_db(struct mic_device *mdev);
-struct mic_irq *mic_request_irq(struct mic_device *mdev,
-	irqreturn_t (*func)(int irq, void *data),
-	const char *name, void *data, int intr_src,
-	enum mic_intr_type type);
-
+struct mic_irq *
+mic_request_threaded_irq(struct mic_device *mdev,
+			 irq_handler_t handler, irq_handler_t thread_fn,
+			 const char *name, void *data, int intr_src,
+			 enum mic_intr_type type);
 void mic_free_irq(struct mic_device *mdev,
 		struct mic_irq *cookie, void *data);
 int mic_setup_interrupts(struct mic_device *mdev, struct pci_dev *pdev);

drivers/misc/mic/host/mic_main.c

···
 	mutex_lock(&mdev->mic_mutex);
 
 	mdev->shutdown_db = mic_next_db(mdev);
-	mdev->shutdown_cookie = mic_request_irq(mdev, mic_shutdown_db,
-		"shutdown-interrupt", mdev, mdev->shutdown_db, MIC_INTR_DB);
+	mdev->shutdown_cookie = mic_request_threaded_irq(mdev, mic_shutdown_db,
+					NULL, "shutdown-interrupt", mdev,
+					mdev->shutdown_db, MIC_INTR_DB);
 	if (IS_ERR(mdev->shutdown_cookie)) {
 		rc = PTR_ERR(mdev->shutdown_cookie);
 		mutex_unlock(&mdev->mic_mutex);

drivers/misc/mic/host/mic_virtio.c

···
 	snprintf(irqname, sizeof(irqname), "mic%dvirtio%d", mdev->id,
 		 mvdev->virtio_id);
 	mvdev->virtio_db = mic_next_db(mdev);
-	mvdev->virtio_cookie = mic_request_irq(mdev, mic_virtio_intr_handler,
-			irqname, mvdev, mvdev->virtio_db, MIC_INTR_DB);
+	mvdev->virtio_cookie = mic_request_threaded_irq(mdev,
+					       mic_virtio_intr_handler,
+					       NULL, irqname, mvdev,
+					       mvdev->virtio_db, MIC_INTR_DB);
 	if (IS_ERR(mvdev->virtio_cookie)) {
 		ret = PTR_ERR(mvdev->virtio_cookie);
 		dev_dbg(mdev->sdev->parent, "request irq failed\n");