dmaengine: introduce dmaengine_bh_wq and bh helpers

index 8fb2d5e1df20..b57f8ebf2446 100644
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/platform_data/amd_qdma.h>
 #include <linux/regmap.h>
+#include <linux/interrupt.h>
 
 #include "qdma.h"
 

index 321748e2983e..08a206cfbb76 100644
@@ -846,7 +846,7 @@ static void bcm2835_dma_free(struct bcm2835_dmadev *od)
 	list_for_each_entry_safe(c, next, &od->ddev.channels,
 				 vc.chan.device_node) {
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 	}
 
 	dma_unmap_page_attrs(od->ddev.dev, od->zero_page, PAGE_SIZE,

138 lines not on this page · raw message

index b23536645ff7..42018b21d2ab 100644
@@ -1649,7 +1649,7 @@ static void dw_remove(struct platform_device *pdev)
 	list_for_each_entry_safe(chan, _chan, &dw->dma.channels,
 			vc.chan.device_node) {
 		list_del(&chan->vc.chan.device_node);
-		tasklet_kill(&chan->vc.task);
+		dma_chan_kill_bh(&chan->vc.chan);
 	}
 }
 

index 8e5f7defa6b6..378650bcc430 100644
@@ -1015,7 +1015,7 @@ int dw_edma_remove(struct dw_edma_chip *chip)
 	dma_async_device_unregister(&dw->dma);
 	list_for_each_entry_safe(chan, _chan, &dw->dma.channels,
 				 vc.chan.device_node) {
-		tasklet_kill(&chan->vc.task);
+		dma_chan_kill_bh(&chan->vc.chan);
 		list_del(&chan->vc.chan.device_node);
 	}
 

index 25a4134be36b..a15491945329 100644
@@ -720,7 +720,7 @@ static void hisi_dma_disable_qps(struct hisi_dma_dev *hdma_dev)
 
 	for (i = 0; i < hdma_dev->chan_num; i++) {
 		hisi_dma_disable_qp(hdma_dev, i);
-		tasklet_kill(&hdma_dev->chan[i].vc.task);
+		dma_chan_kill_bh(&hdma_dev->chan[i].vc.chan);
 	}
 }
 

index fd55bcd060ab..d4f6d839acca 100644
@@ -1031,7 +1031,7 @@ static void mdc_dma_remove(struct platform_device *pdev)
 
 		devm_free_irq(&pdev->dev, mchan->irq, mchan);
 
-		tasklet_kill(&mchan->vc.task);
+		dma_chan_kill_bh(&mchan->vc.chan);
 	}
 
 	pm_runtime_disable(&pdev->dev);

index ed9e56de5a9b..9cbc95fbb4ee 100644
@@ -2427,7 +2427,7 @@ static void sdma_remove(struct platform_device *pdev)
 	for (i = 0; i < MAX_DMA_CHANNELS; i++) {
 		struct sdma_channel *sdmac = &sdma->channel[i];
 
-		tasklet_kill(&sdmac->vc.task);
+		dma_chan_kill_bh(&sdmac->vc.chan);
 		sdma_free_chan_resources(&sdmac->vc.chan);
 	}
 

index 0f9cd7815f88..36d5df545b57 100644
@@ -981,7 +981,7 @@ static void k3_dma_remove(struct platform_device *op)
 
 	list_for_each_entry_safe(c, cn, &d->slave.channels, vc.chan.device_node) {
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 	}
 	tasklet_kill(&d->task);
 	clk_disable_unprepare(d->clk);

index 255fe7eca212..49a78ea1514f 100644
@@ -552,7 +552,7 @@ static void ls1x_dma_chan_remove(struct ls1x_dma *dma)
 
 		if (chan->vc.chan.device == &dma->ddev) {
 			list_del(&chan->vc.chan.device_node);
-			tasklet_kill(&chan->vc.task);
+			dma_chan_kill_bh(&chan->vc.chan);
 		}
 	}
 }

index 9f0c41ca7770..3ba54df12bae 100644
@@ -895,7 +895,7 @@ static void mtk_cqdma_remove(struct platform_device *pdev)
 		vc = &cqdma->vc[i];
 
 		list_del(&vc->vc.chan.device_node);
-		tasklet_kill(&vc->vc.task);
+		dma_chan_kill_bh(&vc->vc.chan);
 	}
 
 	/* disable interrupt */

index fa77bb24a430..0bbf865de24b 100644
@@ -1020,7 +1020,7 @@ static void mtk_hsdma_remove(struct platform_device *pdev)
 		vc = &hsdma->vc[i];
 
 		list_del(&vc->vc.chan.device_node);
-		tasklet_kill(&vc->vc.task);
+		dma_chan_kill_bh(&vc->vc.chan);
 	}
 
 	/* Disable DMA interrupt */

index 08e15177427b..257b9b77cc57 100644
@@ -312,7 +312,7 @@ static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
 
 	free_irq(c->irq, chan);
 
-	tasklet_kill(&c->vc.task);
+	dma_chan_kill_bh(&c->vc.chan);
 
 	vchan_free_chan_resources(&c->vc);
 

@@ -463,7 +463,7 @@ static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
 			struct mtk_chan, vc.chan.device_node);
 
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 	}
 }
 

index 57cec757d8f5..4e6ebf990688 100644
@@ -1055,7 +1055,7 @@ static inline void owl_dma_free(struct owl_dma *od)
 	list_for_each_entry_safe(vchan,
 				 next, &od->dma.channels, vc.chan.device_node) {
 		list_del(&vchan->vc.chan.device_node);
-		tasklet_kill(&vchan->vc.task);
+		dma_chan_kill_bh(&vchan->vc.chan);
 	}
 }
 

index 249296389771..634b723e4891 100644
@@ -1218,7 +1218,7 @@ static void pxad_free_channels(struct dma_device *dmadev)
 	list_for_each_entry_safe(c, cn, &dmadev->channels,
 				 vc.chan.device_node) {
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 	}
 }
 

index 2cf060174795..6ec82adb89ce 100644
@@ -1377,7 +1377,7 @@ static int bam_dma_probe(struct platform_device *pdev)
 	dma_async_device_unregister(&bdev->common);
 err_bam_channel_exit:
 	for (i = 0; i < bdev->num_channels; i++)
-		tasklet_kill(&bdev->channels[i].vc.task);
+		dma_chan_kill_bh(&bdev->channels[i].vc.chan);
 err_tasklet_kill:
 	tasklet_kill(&bdev->task);
 err_disable_clk:

@@ -1403,7 +1403,7 @@ static void bam_dma_remove(struct platform_device *pdev)
 
 	for (i = 0; i < bdev->num_channels; i++) {
 		bam_dma_terminate_all(&bdev->channels[i].vc.chan);
-		tasklet_kill(&bdev->channels[i].vc.task);
+		dma_chan_kill_bh(&bdev->channels[i].vc.chan);
 
 		if (!bdev->channels[i].fifo_virt)
 			continue;

index 6be54fddcee1..0f9e906bd463 100644
@@ -919,7 +919,7 @@ static void adm_dma_remove(struct platform_device *pdev)
 		/* mask IRQs for this channel/EE pair */
 		writel(0, adev->regs + ADM_CH_RSLT_CONF(achan->id, adev->ee));
 
-		tasklet_kill(&adev->channels[i].vc.task);
+		dma_chan_kill_bh(&adev->channels[i].vc.chan);
 		adm_terminate_all(&adev->channels[i].vc.chan);
 	}
 

index dc1a9a05252e..42940079efbf 100644
@@ -893,7 +893,7 @@ static void sa11x0_dma_free_channels(struct dma_device *dmadev)
 
 	list_for_each_entry_safe(c, cn, &dmadev->channels, vc.chan.device_node) {
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 		kfree(c);
 	}
 }

index 6207e0b185e1..5124fe0a93bf 100644
@@ -1253,7 +1253,7 @@ static void sprd_dma_remove(struct platform_device *pdev)
 	list_for_each_entry_safe(c, cn, &sdev->dma_dev.channels,
 				 vc.chan.device_node) {
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 	}
 
 	of_dma_controller_free(pdev->dev.of_node);

index 2215ff877bf7..6b3ab99272a5 100644
@@ -1073,7 +1073,7 @@ static inline void sun6i_dma_free(struct sun6i_dma_dev *sdev)
 		struct sun6i_vchan *vchan = &sdev->vchans[i];
 
 		list_del(&vchan->vc.chan.device_node);
-		tasklet_kill(&vchan->vc.task);
+		dma_chan_kill_bh(&vchan->vc.chan);
 	}
 }
 

index 4d6fe0efa76e..3b9dc64eb635 100644
@@ -1279,7 +1279,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
 	tegra_dma_terminate_all(dc);
 	synchronize_irq(tdc->irq);
 
-	tasklet_kill(&tdc->vc.task);
+	dma_chan_kill_bh(&tdc->vc.chan);
 	tdc->config_init = false;
 	tdc->slave_id = -1;
 	tdc->sid_dir = DMA_TRANS_NONE;

index d0e8bb27a03b..67ccb1d48361 100644
@@ -793,7 +793,7 @@ static void tegra_adma_free_chan_resources(struct dma_chan *dc)
 
 	tegra_adma_terminate_all(dc);
 	vchan_free_chan_resources(&tdc->vc);
-	tasklet_kill(&tdc->vc.task);
+	dma_chan_kill_bh(&tdc->vc.chan);
 	free_irq(tdc->irq, tdc);
 	pm_runtime_put(tdc2dev(tdc));
 

index aa2dc762140f..89dd7926705d 100644
@@ -4045,9 +4045,9 @@ static void udma_desc_pre_callback(struct virt_dma_chan *vc,
  * This tasklet handles the completion of a DMA descriptor by
  * calling its callback and freeing it.
  */
-static void udma_vchan_complete(struct tasklet_struct *t)
+static void udma_vchan_complete(struct dma_chan *chan)
 {
-	struct virt_dma_chan *vc = from_tasklet(vc, t, task);
+	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct virt_dma_desc *vd, *_vd;
 	struct dmaengine_desc_callback cb;
 	LIST_HEAD(head);

@@ -4112,7 +4112,7 @@ static void udma_free_chan_resources(struct dma_chan *chan)
 	}
 
 	vchan_free_chan_resources(&uc->vc);
-	tasklet_kill(&uc->vc.task);
+	dma_chan_kill_bh(&uc->vc.chan);
 
 	bcdma_free_bchan_resources(uc);
 	udma_free_tx_resources(uc);

@@ -5628,7 +5628,7 @@ static int udma_probe(struct platform_device *pdev)
 			return -ENOMEM;
 		vchan_init(&uc->vc, &ud->ddev);
 		/* Use custom vchan completion handling */
-		tasklet_setup(&uc->vc.task, udma_vchan_complete);
+		dma_chan_init_bh(&uc->vc.chan, udma_vchan_complete);
 		init_completion(&uc->teardown_completed);
 		INIT_DELAYED_WORK(&uc->tx_drain.work, udma_check_tx_completion);
 	}

index 8c023c6e623a..f6aee92071e2 100644
@@ -1521,7 +1521,7 @@ static void omap_dma_free(struct omap_dmadev *od)
 			struct omap_chan, vc.chan.device_node);
 
 		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
+		dma_chan_kill_bh(&c->vc.chan);
 		kfree(c);
 	}
 }

index 7961172a780d..c311397f3bd7 100644
@@ -80,9 +80,9 @@ EXPORT_SYMBOL_GPL(vchan_find_desc);
  * This tasklet handles the completion of a DMA descriptor by
  * calling its callback and freeing it.
  */
-static void vchan_complete(struct tasklet_struct *t)
+static void vchan_complete(struct dma_chan *chan)
 {
-	struct virt_dma_chan *vc = from_tasklet(vc, t, task);
+	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct virt_dma_desc *vd, *_vd;
 	struct dmaengine_desc_callback cb;
 	LIST_HEAD(head);

@@ -131,7 +131,7 @@ void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev)
 	INIT_LIST_HEAD(&vc->desc_completed);
 	INIT_LIST_HEAD(&vc->desc_terminated);
 
-	tasklet_setup(&vc->task, vchan_complete);
+	dma_chan_init_bh(&vc->chan, vchan_complete);
 
 	vc->chan.device = dmadev;
 	list_add_tail(&vc->chan.device_node, &dmadev->channels);

index 59d9eabc8b67..5299fb7367ca 100644
@@ -8,7 +8,6 @@
 #define VIRT_DMA_H
 
 #include <linux/dmaengine.h>
-#include <linux/interrupt.h>
 
 #include "dmaengine.h"
 

@@ -21,7 +20,6 @@ struct virt_dma_desc {
 
 struct virt_dma_chan {
 	struct dma_chan	chan;
-	struct tasklet_struct task;
 	void (*desc_free)(struct virt_dma_desc *);
 
 	spinlock_t lock;

@@ -106,7 +104,7 @@ static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
 		 vd, cookie);
 	list_add_tail(&vd->node, &vc->desc_completed);
 
-	tasklet_schedule(&vc->task);
+	dma_chan_schedule_bh(&vc->chan);
 }
 
 /**

@@ -137,7 +135,7 @@ static inline void vchan_cyclic_callback(struct virt_dma_desc *vd)
 	struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
 
 	vc->cyclic = vd;
-	tasklet_schedule(&vc->task);
+	dma_chan_schedule_bh(&vc->chan);
 }
 
 /**

@@ -223,7 +221,7 @@ static inline void vchan_synchronize(struct virt_dma_chan *vc)
 	LIST_HEAD(head);
 	unsigned long flags;
 
-	tasklet_kill(&vc->task);
+	dma_chan_kill_bh(&vc->chan);
 
 	spin_lock_irqsave(&vc->lock, flags);
 

86 lines not on this page · raw message

index 9049171df857..f43aeecb47f9 100644
@@ -1428,6 +1428,48 @@ static void dmaengine_destroy_unmap_pool(void)
 	}
 }
 
+static void dma_chan_bh_entry(struct tasklet_struct *tasklet)
+{
+	struct dma_chan *chan = from_tasklet(chan, tasklet, bh_tasklet);
+	dma_chan_bh_work_fn fn = READ_ONCE(chan->bh_work_fn);
+
+	if (fn)
+		fn(chan);
+}
+
+void dma_chan_init_bh(struct dma_chan *chan, dma_chan_bh_work_fn fn)
+{
+	if (WARN_ON(!fn))
+		return;
+
+	if (WARN_ON(chan->bh_work_initialized))
+		return;
+
+	chan->bh_work_fn = fn;
+	tasklet_setup(&chan->bh_tasklet, dma_chan_bh_entry);
+	chan->bh_work_initialized = true;
+}
+EXPORT_SYMBOL_GPL(dma_chan_init_bh);
+
+bool dma_chan_schedule_bh(struct dma_chan *chan)
+{
+	if (WARN_ON(!chan->bh_work_initialized))
+		return false;
+
+	tasklet_schedule(&chan->bh_tasklet);
+	return true;
+}
+EXPORT_SYMBOL_GPL(dma_chan_schedule_bh);
+
+void dma_chan_kill_bh(struct dma_chan *chan)
+{
+	if (!chan->bh_work_initialized)
+		return;
+
+	tasklet_kill(&chan->bh_tasklet);
+}
+EXPORT_SYMBOL_GPL(dma_chan_kill_bh);
+
 static int __init dmaengine_init_unmap_pool(void)
 {
 	int i;

index 7961172a780d..89fcd51ddcab 100644
@@ -77,12 +77,12 @@ struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *vc,
 EXPORT_SYMBOL_GPL(vchan_find_desc);
 
 /*
- * This tasklet handles the completion of a DMA descriptor by
- * calling its callback and freeing it.
+ * This bottom-half handler completes a DMA descriptor by invoking its
+ * callback and freeing it.
  */
-static void vchan_complete(struct tasklet_struct *t)
+static void vchan_complete(struct dma_chan *chan)
 {
-	struct virt_dma_chan *vc = from_tasklet(vc, t, task);
+	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct virt_dma_desc *vd, *_vd;
 	struct dmaengine_desc_callback cb;
 	LIST_HEAD(head);

@@ -98,7 +98,7 @@ static void vchan_complete(struct tasklet_struct *t)
 	}
 	spin_unlock_irq(&vc->lock);
 
-	dmaengine_desc_callback_invoke(&cb, &vd->tx_result);
+	dmaengine_desc_callback_invoke(&cb, vd ? &vd->tx_result : NULL);
 
 	list_for_each_entry_safe(vd, _vd, &head, node) {
 		dmaengine_desc_get_callback(&vd->tx, &cb);

@@ -131,7 +131,7 @@ void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev)
 	INIT_LIST_HEAD(&vc->desc_completed);
 	INIT_LIST_HEAD(&vc->desc_terminated);
 
-	tasklet_setup(&vc->task, vchan_complete);
+	dma_chan_init_bh(&vc->chan, vchan_complete);
 
 	vc->chan.device = dmadev;
 	list_add_tail(&vc->chan.device_node, &dmadev->channels);

index 59d9eabc8b67..abe2a4475744 100644
@@ -21,7 +21,6 @@ struct virt_dma_desc {
 
 struct virt_dma_chan {
 	struct dma_chan	chan;
-	struct tasklet_struct task;
 	void (*desc_free)(struct virt_dma_desc *);
 
 	spinlock_t lock;

@@ -106,7 +105,7 @@ static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
 		 vd, cookie);
 	list_add_tail(&vd->node, &vc->desc_completed);
 
-	tasklet_schedule(&vc->task);
+	dma_chan_schedule_bh(&vc->chan);
 }
 
 /**

@@ -137,7 +136,7 @@ static inline void vchan_cyclic_callback(struct virt_dma_desc *vd)
 	struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
 
 	vc->cyclic = vd;
-	tasklet_schedule(&vc->task);
+	dma_chan_schedule_bh(&vc->chan);
 }
 
 /**

@@ -223,7 +222,7 @@ static inline void vchan_synchronize(struct virt_dma_chan *vc)
 	LIST_HEAD(head);
 	unsigned long flags;
 
-	tasklet_kill(&vc->task);
+	dma_chan_kill_bh(&vc->chan);
 
 	spin_lock_irqsave(&vc->lock, flags);
 

index b3d251c9734e..c670781b3150 100644
@@ -12,6 +12,7 @@
 #include <linux/scatterlist.h>
 #include <linux/bitmap.h>
 #include <linux/types.h>
+#include <linux/interrupt.h>
 #include <asm/page.h>
 
 /**

@@ -295,6 +296,10 @@ enum dma_desc_metadata_mode {
 	DESC_METADATA_ENGINE = BIT(1),
 };
 
+struct dma_chan;
+
+typedef void (*dma_chan_bh_work_fn)(struct dma_chan *chan);
+
 /**
  * struct dma_chan_percpu - the per-CPU part of struct dma_chan
  * @memcpy_count: transaction counter

@@ -334,6 +339,9 @@ struct dma_router {
  * @router: pointer to the DMA router structure
  * @route_data: channel specific data for the router
  * @private: private data for certain client-channel associations
+ * @bh_tasklet: bottom-half tasklet stored per-channel
+ * @bh_work_fn: callback executed when @bh_tasklet runs
+ * @bh_work_initialized: indicates whether @bh_tasklet has been initialized
  */
 struct dma_chan {
 	struct dma_device *device;

@@ -359,6 +367,9 @@ struct dma_chan {
 	void *route_data;
 
 	void *private;
+	struct tasklet_struct bh_tasklet;
+	dma_chan_bh_work_fn bh_work_fn;
+	bool bh_work_initialized;
 };
 
 /**

@@ -1529,6 +1540,9 @@ struct dma_chan *devm_dma_request_chan(struct device *dev, const char *name);
 
 void dma_release_channel(struct dma_chan *chan);
 int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
+void dma_chan_init_bh(struct dma_chan *chan, dma_chan_bh_work_fn fn);
+bool dma_chan_schedule_bh(struct dma_chan *chan);
+void dma_chan_kill_bh(struct dma_chan *chan);
 #else
 static inline struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
 {

@@ -1576,6 +1590,20 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
 {
 	return -ENXIO;
 }
+
+static inline void dma_chan_init_bh(struct dma_chan *chan,
+				    dma_chan_bh_work_fn fn)
+{
+}
+
+static inline bool dma_chan_schedule_bh(struct dma_chan *chan)
+{
+	return false;
+}
+
+static inline void dma_chan_kill_bh(struct dma_chan *chan)
+{
+}
 #endif
 
 static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)

index f43aeecb47f9..8b1b17794956 100644
@@ -54,6 +54,7 @@
 #include <linux/rcupdate.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/workqueue.h>
 
 #include "dmaengine.h"
 

@@ -61,6 +62,7 @@ static DEFINE_MUTEX(dma_list_mutex);
 static DEFINE_IDA(dma_ida);
 static LIST_HEAD(dma_device_list);
 static long dmaengine_ref_count;
+static struct workqueue_struct *dmaengine_bh_wq;
 
 /* --- debugfs implementation --- */
 #ifdef CONFIG_DEBUG_FS

@@ -1428,9 +1430,34 @@ static void dmaengine_destroy_unmap_pool(void)
 	}
 }
 
-static void dma_chan_bh_entry(struct tasklet_struct *tasklet)
+static void dmaengine_destroy_bh_wq(void)
 {
-	struct dma_chan *chan = from_tasklet(chan, tasklet, bh_tasklet);
+	if (!dmaengine_bh_wq)
+		return;
+
+	destroy_workqueue(dmaengine_bh_wq);
+	dmaengine_bh_wq = NULL;
+}
+
+static bool dmaengine_queue_bh_work(struct work_struct *work)
+{
+	if (WARN_ON(!dmaengine_bh_wq))
+		return false;
+
+	return queue_work(dmaengine_bh_wq, work);
+}
+
+static void dmaengine_flush_bh_work(struct work_struct *work)
+{
+	if (!work)
+		return;
+
+	flush_work(work);
+}
+
+static void dma_chan_bh_entry(struct work_struct *work)
+{
+	struct dma_chan *chan = container_of(work, struct dma_chan, bh_work);
 	dma_chan_bh_work_fn fn = READ_ONCE(chan->bh_work_fn);
 
 	if (fn)

@@ -1446,7 +1473,7 @@ void dma_chan_init_bh(struct dma_chan *chan, dma_chan_bh_work_fn fn)
 		return;
 
 	chan->bh_work_fn = fn;
-	tasklet_setup(&chan->bh_tasklet, dma_chan_bh_entry);
+	INIT_WORK(&chan->bh_work, dma_chan_bh_entry);
 	chan->bh_work_initialized = true;
 }
 EXPORT_SYMBOL_GPL(dma_chan_init_bh);

@@ -1456,8 +1483,7 @@ bool dma_chan_schedule_bh(struct dma_chan *chan)
 	if (WARN_ON(!chan->bh_work_initialized))
 		return false;
 
-	tasklet_schedule(&chan->bh_tasklet);
-	return true;
+	return dmaengine_queue_bh_work(&chan->bh_work);
 }
 EXPORT_SYMBOL_GPL(dma_chan_schedule_bh);
 

@@ -1466,7 +1492,7 @@ void dma_chan_kill_bh(struct dma_chan *chan)
 	if (!chan->bh_work_initialized)
 		return;
 
-	tasklet_kill(&chan->bh_tasklet);
+	dmaengine_flush_bh_work(&chan->bh_work);
 }
 EXPORT_SYMBOL_GPL(dma_chan_kill_bh);
 

@@ -1666,15 +1692,28 @@ EXPORT_SYMBOL_GPL(dma_run_dependencies);
 
 static int __init dma_bus_init(void)
 {
-	int err = dmaengine_init_unmap_pool();
+	int err;
 
+	dmaengine_bh_wq = alloc_workqueue("dmaengine_bh",
+					  WQ_BH | WQ_PERCPU, 0);
+	if (!dmaengine_bh_wq)
+		return -ENOMEM;
+
+	err = dmaengine_init_unmap_pool();
 	if (err)
-		return err;
+		goto err_destroy_wq;
 
 	err = class_register(&dma_devclass);
-	if (!err)
-		dmaengine_debugfs_init();
+	if (err)
+		goto err_destroy_pool;
 
+	dmaengine_debugfs_init();
+	return 0;
+
+err_destroy_pool:
+	dmaengine_destroy_unmap_pool();
+err_destroy_wq:
+	dmaengine_destroy_bh_wq();
 	return err;
 }
 arch_initcall(dma_bus_init);

index c670781b3150..c87974d5048b 100644
@@ -12,7 +12,7 @@
 #include <linux/scatterlist.h>
 #include <linux/bitmap.h>
 #include <linux/types.h>
-#include <linux/interrupt.h>
+#include <linux/workqueue.h>
 #include <asm/page.h>
 
 /**

@@ -339,9 +339,9 @@ struct dma_router {
  * @router: pointer to the DMA router structure
  * @route_data: channel specific data for the router
  * @private: private data for certain client-channel associations
- * @bh_tasklet: bottom-half tasklet stored per-channel
- * @bh_work_fn: callback executed when @bh_tasklet runs
- * @bh_work_initialized: indicates whether @bh_tasklet has been initialized
+ * @bh_work: bottom-half work item stored per-channel
+ * @bh_work_fn: callback executed when @bh_work runs
+ * @bh_work_initialized: indicates whether @bh_work has been initialized
  */
 struct dma_chan {
 	struct dma_device *device;

@@ -367,7 +367,7 @@ struct dma_chan {
 	void *route_data;
 
 	void *private;
-	struct tasklet_struct bh_tasklet;
+	struct work_struct bh_work;
 	dma_chan_bh_work_fn bh_work_fn;
 	bool bh_work_initialized;
 };

index 14a5ee14a481..84483247bde6 100644
@@ -89,7 +89,6 @@ struct admac_chan {
 	unsigned int no;
 	struct admac_data *host;
 	struct dma_chan chan;
-	struct tasklet_struct tasklet;
 
 	u32 carveout;
 

@@ -521,10 +520,7 @@ static int admac_terminate_all(struct dma_chan *chan)
 		list_add_tail(&adchan->current_tx->node, &adchan->to_free);
 		adchan->current_tx = NULL;
 	}
-	/*
-	 * Descriptors can only be freed after the tasklet
-	 * has been killed (in admac_synchronize).
-	 */
+	/* Descriptors are released once the BH is flushed in admac_synchronize */
 	list_splice_tail_init(&adchan->submitted, &adchan->to_free);
 	list_splice_tail_init(&adchan->issued, &adchan->to_free);
 	spin_unlock_irqrestore(&adchan->lock, flags);

@@ -543,7 +539,7 @@ static void admac_synchronize(struct dma_chan *chan)
 	list_splice_tail_init(&adchan->to_free, &head);
 	spin_unlock_irqrestore(&adchan->lock, flags);
 
-	tasklet_kill(&adchan->tasklet);
+	dma_chan_kill_bh(&adchan->chan);
 
 	list_for_each_entry_safe(adtx, _adtx, &head, node) {
 		list_del(&adtx->node);

@@ -662,7 +658,7 @@ static void admac_handle_status_desc_done(struct admac_data *ad, int channo)
 		tx->reclaimed_pos %= 2 * tx->buf_len;
 
 		admac_cyclic_write_desc(ad, channo, tx);
-		tasklet_schedule(&adchan->tasklet);
+		dma_chan_schedule_bh(&adchan->chan);
 	}
 	spin_unlock_irqrestore(&adchan->lock, flags);
 }

@@ -712,9 +708,9 @@ static irqreturn_t admac_interrupt(int irq, void *devid)
 	return IRQ_HANDLED;
 }
 
-static void admac_chan_tasklet(struct tasklet_struct *t)
+static void admac_chan_bh(struct dma_chan *chan)
 {
-	struct admac_chan *adchan = from_tasklet(adchan, t, tasklet);
+	struct admac_chan *adchan = to_admac_chan(chan);
 	struct admac_tx *adtx;
 	struct dmaengine_desc_callback cb;
 	struct dmaengine_result tx_result;

@@ -886,7 +882,7 @@ static int admac_probe(struct platform_device *pdev)
 		INIT_LIST_HEAD(&adchan->issued);
 		INIT_LIST_HEAD(&adchan->to_free);
 		list_add_tail(&adchan->chan.device_node, &dma->channels);
-		tasklet_setup(&adchan->tasklet, admac_chan_tasklet);
+		dma_chan_init_bh(&adchan->chan, admac_chan_bh);
 	}
 
 	err = reset_control_reset(ad->rstc);

index 901971e8bae6..aa918043e37e 100644
@@ -228,7 +228,6 @@ struct at_xdmac_chan {
 	u32				save_cndc;
 	u32				irq_status;
 	unsigned long			status;
-	struct tasklet_struct		tasklet;
 	struct dma_slave_config		sconfig;
 
 	spinlock_t			lock;

@@ -1759,9 +1758,9 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
 	/* Then continue with usual descriptor management */
 }
 
-static void at_xdmac_tasklet(struct tasklet_struct *t)
+static void at_xdmac_tasklet(struct dma_chan *chan)
 {
-	struct at_xdmac_chan	*atchan = from_tasklet(atchan, t, tasklet);
+	struct at_xdmac_chan	*atchan = to_at_xdmac_chan(chan);
 	struct at_xdmac		*atxdmac = to_at_xdmac(atchan->chan.device);
 	struct at_xdmac_desc	*desc;
 	struct dma_async_tx_descriptor *txd;

@@ -1865,7 +1864,7 @@ static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)
 			if (atchan->irq_status & (AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS))
 				at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
 
-			tasklet_schedule(&atchan->tasklet);
+			dma_chan_schedule_bh(&atchan->chan);
 			ret = IRQ_HANDLED;
 		}
 

@@ -2317,7 +2316,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
 		return PTR_ERR(atxdmac->clk);
 	}
 
-	/* Do not use dev res to prevent races with tasklet */
+	/* Do not use devm resources to prevent races with the BH worker */
 	ret = request_irq(atxdmac->irq, at_xdmac_interrupt, 0, "at_xdmac", atxdmac);
 	if (ret) {
 		dev_err(&pdev->dev, "can't request irq\n");

@@ -2397,7 +2396,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
 		spin_lock_init(&atchan->lock);
 		INIT_LIST_HEAD(&atchan->xfers_list);
 		INIT_LIST_HEAD(&atchan->free_descs_list);
-		tasklet_setup(&atchan->tasklet, at_xdmac_tasklet);
+		dma_chan_init_bh(&atchan->chan, at_xdmac_tasklet);
 
 		/* Clear pending interrupts. */
 		while (at_xdmac_chan_read(atchan, AT_XDMAC_CIS))

@@ -2458,7 +2457,7 @@ static void at_xdmac_remove(struct platform_device *pdev)
 	for (i = 0; i < atxdmac->dma.chancnt; i++) {
 		struct at_xdmac_chan *atchan = &atxdmac->chan[i];
 
-		tasklet_kill(&atchan->tasklet);
+		dma_chan_kill_bh(&atchan->chan);
 		at_xdmac_free_chan_resources(&atchan->chan);
 	}
 }

index 311e55a97ba9..8f5200750fe9 100644
@@ -167,7 +167,6 @@ struct ep93xx_dma_chan_cfg {
  * @dma_cfg: channel number, direction
  * @irq: interrupt number of the channel
  * @clk: clock used by this channel
- * @tasklet: channel specific tasklet used for callbacks
  * @lock: lock protecting the fields following
  * @flags: flags for the channel
  * @buffer: which buffer to use next (0/1)

@@ -196,7 +195,6 @@ struct ep93xx_dma_chan {
 	struct ep93xx_dma_chan_cfg	dma_cfg;
 	int				irq;
 	struct clk			*clk;
-	struct tasklet_struct		tasklet;
 	/* protects the fields following */
 	spinlock_t			lock;
 	unsigned long			flags;

@@ -801,9 +799,9 @@ static void ep93xx_dma_advance_work(struct ep93xx_dma_chan *edmac)
 	spin_unlock_irqrestore(&edmac->lock, flags);
 }
 
-static void ep93xx_dma_tasklet(struct tasklet_struct *t)
+static void ep93xx_dma_tasklet(struct dma_chan *chan)
 {
-	struct ep93xx_dma_chan *edmac = from_tasklet(edmac, t, tasklet);
+	struct ep93xx_dma_chan *edmac = to_ep93xx_dma_chan(chan);
 	struct ep93xx_dma_desc *desc, *d;
 	struct dmaengine_desc_callback cb;
 	LIST_HEAD(list);

@@ -858,12 +856,12 @@ static irqreturn_t ep93xx_dma_interrupt(int irq, void *dev_id)
 	switch (edmac->edma->hw_interrupt(edmac)) {
 	case INTERRUPT_DONE:
 		desc->complete = true;
-		tasklet_schedule(&edmac->tasklet);
+		dma_chan_schedule_bh(&edmac->chan);
 		break;
 
 	case INTERRUPT_NEXT_BUFFER:
 		if (test_bit(EP93XX_DMA_IS_CYCLIC, &edmac->flags))
-			tasklet_schedule(&edmac->tasklet);
+			dma_chan_schedule_bh(&edmac->chan);
 		break;
 
 	default:

@@ -1420,7 +1418,7 @@ static struct ep93xx_dma_engine *ep93xx_dma_of_probe(struct platform_device *pde
 		INIT_LIST_HEAD(&edmac->active);
 		INIT_LIST_HEAD(&edmac->queue);
 		INIT_LIST_HEAD(&edmac->free_list);
-		tasklet_setup(&edmac->tasklet, ep93xx_dma_tasklet);
+		dma_chan_init_bh(&edmac->chan, ep93xx_dma_tasklet);
 
 		list_add_tail(&edmac->chan.device_node,
 			      &dma_dev->channels);

index 22d62d958abd..1cb6ce327078 100644
@@ -968,18 +968,18 @@ static irqreturn_t fsldma_chan_irq(int irq, void *data)
 		chan_err(chan, "irq: unhandled sr 0x%08x\n", stat);
 
 	/*
-	 * Schedule the tasklet to handle all cleanup of the current
+	 * Queue the BH worker to handle all cleanup of the current
 	 * transaction. It will start a new transaction if there is
 	 * one pending.
 	 */
-	tasklet_schedule(&chan->tasklet);
+	dma_chan_schedule_bh(&chan->common);
 	chan_dbg(chan, "irq: Exit\n");
 	return IRQ_HANDLED;
 }
 
-static void dma_do_tasklet(struct tasklet_struct *t)
+static void dma_do_tasklet(struct dma_chan *c)
 {
-	struct fsldma_chan *chan = from_tasklet(chan, t, tasklet);
+	struct fsldma_chan *chan = to_fsl_chan(c);
 
 	chan_dbg(chan, "tasklet entry\n");
 

@@ -1152,7 +1152,7 @@ static int fsl_dma_chan_probe(struct fsldma_device *fdev,
 	}
 
 	fdev->chan[chan->id] = chan;
-	tasklet_setup(&chan->tasklet, dma_do_tasklet);
+	dma_chan_init_bh(&chan->common, dma_do_tasklet);
 	snprintf(chan->name, sizeof(chan->name), "chan%d", chan->id);
 
 	/* Initialize the channel */

index d7b7a3138b85..cab33d010d51 100644
@@ -173,7 +173,6 @@ struct fsldma_chan {
 	struct device *dev;		/* Channel device */
 	int irq;			/* Channel IRQ */
 	int id;				/* Raw id of this channel */
-	struct tasklet_struct tasklet;
 	u32 feature;
 	bool idle;			/* DMA controller is idle */
 #ifdef CONFIG_PM

index 99945845d8b5..e91c18d3c327 100644
@@ -155,9 +155,10 @@ static void fsl_re_cleanup_descs(struct fsl_re_chan *re_chan)
 	fsl_re_issue_pending(&re_chan->chan);
 }
 
-static void fsl_re_dequeue(struct tasklet_struct *t)
+static void fsl_re_dequeue(struct dma_chan *chan)
 {
-	struct fsl_re_chan *re_chan = from_tasklet(re_chan, t, irqtask);
+	struct fsl_re_chan *re_chan = container_of(chan, struct fsl_re_chan,
+						   chan);
 	struct fsl_re_desc *desc, *_desc;
 	struct fsl_re_hw_desc *hwdesc;
 	unsigned long flags;

@@ -224,7 +225,7 @@ static irqreturn_t fsl_re_isr(int irq, void *data)
 	/* Clear interrupt */
 	out_be32(&re_chan->jrregs->jr_interrupt_status, FSL_RE_CLR_INTR);
 
-	tasklet_schedule(&re_chan->irqtask);
+	dma_chan_schedule_bh(&re_chan->chan);
 
 	return IRQ_HANDLED;
 }

@@ -670,7 +671,7 @@ static int fsl_re_chan_probe(struct platform_device *ofdev,
 	snprintf(chan->name, sizeof(chan->name), "re_jr%02d", q);
 
 	chandev = &chan_ofdev->dev;
-	tasklet_setup(&chan->irqtask, fsl_re_dequeue);
+	dma_chan_init_bh(&chan->chan, fsl_re_dequeue);
 
 	ret = request_irq(chan->irq, fsl_re_isr, 0, chan->name, chandev);
 	if (ret) {

@@ -846,7 +847,7 @@ static int fsl_re_probe(struct platform_device *ofdev)
 
 static void fsl_re_remove_chan(struct fsl_re_chan *chan)
 {
-	tasklet_kill(&chan->irqtask);
+	dma_chan_kill_bh(&chan->chan);
 
 	dma_pool_free(chan->re_dev->hw_desc_pool, chan->inb_ring_virt_addr,
 		      chan->inb_phys_addr);

index 69d743c04973..a40001a4db58 100644
@@ -275,7 +275,6 @@ struct fsl_re_chan {
 	struct dma_chan chan;
 	struct fsl_re_chan_cfg *jrregs;
 	int irq;
-	struct tasklet_struct irqtask;
 	u32 alloc_count;
 
 	/* hw descriptor ring for inbound queue*/

index 81c6276436f8..3ff0bfbfa5ff 100644
@@ -145,7 +145,6 @@ struct imxdma_channel {
 	struct imxdma_engine		*imxdma;
 	unsigned int			channel;
 
-	struct tasklet_struct		dma_tasklet;
 	struct list_head		ld_free;
 	struct list_head		ld_queue;
 	struct list_head		ld_active;

@@ -344,8 +343,8 @@ static void imxdma_watchdog(struct timer_list *t)
 
 	imx_dmav1_writel(imxdma, 0, DMA_CCR(channel));
 
-	/* Tasklet watchdog error handler */
-	tasklet_schedule(&imxdmac->dma_tasklet);
+	/* BH watchdog error handler */
+	dma_chan_schedule_bh(&imxdmac->chan);
 	dev_dbg(imxdma->dev, "channel %d: watchdog timeout!\n",
 		imxdmac->channel);
 }

@@ -390,8 +389,8 @@ static irqreturn_t imxdma_err_handler(int irq, void *dev_id)
 			imx_dmav1_writel(imxdma, 1 << i, DMA_DBOSR);
 			errcode |= IMX_DMA_ERR_BUFFER;
 		}
-		/* Tasklet error handler */
-		tasklet_schedule(&imxdma->channel[i].dma_tasklet);
+		/* BH error handler */
+		dma_chan_schedule_bh(&imxdma->channel[i].chan);
 
 		dev_warn(imxdma->dev,
 			 "DMA timeout on channel %d -%s%s%s%s\n", i,

@@ -448,8 +447,8 @@ static void dma_irq_handle_channel(struct imxdma_channel *imxdmac)
 			imx_dmav1_writel(imxdma, tmp, DMA_CCR(chno));
 
 			if (imxdma_chan_is_doing_cyclic(imxdmac))
-				/* Tasklet progression */
-				tasklet_schedule(&imxdmac->dma_tasklet);
+				/* BH progression */
+				dma_chan_schedule_bh(&imxdmac->chan);
 
 			return;
 		}

@@ -462,8 +461,8 @@ static void dma_irq_handle_channel(struct imxdma_channel *imxdmac)
 
 out:
 	imx_dmav1_writel(imxdma, 0, DMA_CCR(chno));
-	/* Tasklet irq */
-	tasklet_schedule(&imxdmac->dma_tasklet);
+	/* Schedule the IRQ BH */
+	dma_chan_schedule_bh(&imxdmac->chan);
 }
 
 static irqreturn_t dma_irq_handler(int irq, void *dev_id)

@@ -592,9 +591,10 @@ static int imxdma_xfer_desc(struct imxdma_desc *d)
 	return 0;
 }
 
-static void imxdma_tasklet(struct tasklet_struct *t)
+static void imxdma_tasklet(struct dma_chan *chan)
 {
-	struct imxdma_channel *imxdmac = from_tasklet(imxdmac, t, dma_tasklet);
+	struct imxdma_channel *imxdmac = container_of(chan, struct imxdma_channel,
+						      chan);
 	struct imxdma_engine *imxdma = imxdmac->imxdma;
 	struct imxdma_desc *desc, *next_desc;
 	unsigned long flags;

@@ -1142,7 +1142,7 @@ static int __init imxdma_probe(struct platform_device *pdev)
 		INIT_LIST_HEAD(&imxdmac->ld_free);
 		INIT_LIST_HEAD(&imxdmac->ld_active);
 
-		tasklet_setup(&imxdmac->dma_tasklet, imxdma_tasklet);
+		dma_chan_init_bh(&imxdmac->chan, imxdma_tasklet);
 		imxdmac->chan.device = &imxdma->dma_device;
 		dma_cookie_init(&imxdmac->chan);
 		imxdmac->channel = i;

@@ -1211,7 +1211,7 @@ static void imxdma_free_irq(struct platform_device *pdev, struct imxdma_engine *
 		if (!is_imx1_dma(imxdma))
 			disable_irq(imxdmac->irq);
 
-		tasklet_kill(&imxdmac->dma_tasklet);
+		dma_chan_kill_bh(&imxdmac->chan);
 	}
 }
 

index ee93b029f9e3..827b46c6354a 100644
@@ -110,7 +110,7 @@ irqreturn_t ioat_dma_do_interrupt(int irq, void *data)
 	for_each_set_bit(bit, &attnstatus, BITS_PER_LONG) {
 		ioat_chan = ioat_chan_by_index(instance, bit);
 		if (test_bit(IOAT_RUN, &ioat_chan->state))
-			tasklet_schedule(&ioat_chan->cleanup_task);
+			dma_chan_schedule_bh(&ioat_chan->dma_chan);
 	}
 
 	writeb(intrctrl, instance->reg_base + IOAT_INTRCTRL_OFFSET);

@@ -127,7 +127,7 @@ irqreturn_t ioat_dma_do_interrupt_msix(int irq, void *data)
 	struct ioatdma_chan *ioat_chan = data;
 
 	if (test_bit(IOAT_RUN, &ioat_chan->state))
-		tasklet_schedule(&ioat_chan->cleanup_task);
+		dma_chan_schedule_bh(&ioat_chan->dma_chan);
 
 	return IRQ_HANDLED;
 }

@@ -161,11 +161,11 @@ void ioat_stop(struct ioatdma_chan *ioat_chan)
 	/* flush inflight timers */
 	timer_delete_sync(&ioat_chan->timer);
 
-	/* flush inflight tasklet runs */
-	tasklet_kill(&ioat_chan->cleanup_task);
+	/* flush inflight BH runs */
+	dma_chan_kill_bh(&ioat_chan->dma_chan);
 
 	/* final cleanup now that everything is quiesced and can't re-arm */
-	ioat_cleanup_event(&ioat_chan->cleanup_task);
+	ioat_cleanup_event(&ioat_chan->dma_chan);
 }
 
 static void __ioat_issue_pending(struct ioatdma_chan *ioat_chan)

@@ -690,9 +690,9 @@ static void ioat_cleanup(struct ioatdma_chan *ioat_chan)
 	spin_unlock_bh(&ioat_chan->cleanup_lock);
 }
 
-void ioat_cleanup_event(struct tasklet_struct *t)
+void ioat_cleanup_event(struct dma_chan *c)
 {
-	struct ioatdma_chan *ioat_chan = from_tasklet(ioat_chan, t, cleanup_task);
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
 
 	ioat_cleanup(ioat_chan);
 	if (!test_bit(IOAT_RUN, &ioat_chan->state))

index e8a880f338c6..4bdb1ae937e4 100644
@@ -111,7 +111,6 @@ struct ioatdma_chan {
 	struct ioatdma_device *ioat_dma;
 	dma_addr_t completion_dma;
 	u64 *completion;
-	struct tasklet_struct cleanup_task;
 	struct kobject kobj;
 
 /* ioat v2 / v3 channel attributes

@@ -385,7 +384,7 @@ int ioat_reset_hw(struct ioatdma_chan *ioat_chan);
 enum dma_status
 ioat_tx_status(struct dma_chan *c, dma_cookie_t cookie,
 		struct dma_tx_state *txstate);
-void ioat_cleanup_event(struct tasklet_struct *t);
+void ioat_cleanup_event(struct dma_chan *c);
 void ioat_timer_event(struct timer_list *t);
 int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs);
 void ioat_issue_pending(struct dma_chan *chan);

index 737496391109..314676e1cbc4 100644
@@ -765,7 +765,7 @@ ioat_init_channel(struct ioatdma_device *ioat_dma,
 	list_add_tail(&ioat_chan->dma_chan.device_node, &dma->channels);
 	ioat_dma->idx[idx] = ioat_chan;
 	timer_setup(&ioat_chan->timer, ioat_timer_event, 0);
-	tasklet_setup(&ioat_chan->cleanup_task, ioat_cleanup_event);
+	dma_chan_init_bh(&ioat_chan->dma_chan, ioat_cleanup_event);
 }
 
 #define IOAT_NUM_SRC_TEST 6 /* must be <= 8 */

index 386e85cd4882..3fd9ef59a142 100644
@@ -116,7 +116,6 @@ struct mmp_pdma_chan {
 						 * is in cyclic mode */
 
 	/* channel's basic info */
-	struct tasklet_struct tasklet;
 	u32 dcmd;
 	u32 drcmr;
 	u32 dev_addr;

@@ -374,7 +373,7 @@ static irqreturn_t mmp_pdma_chan_handler(int irq, void *dev_id)
 	if (clear_chan_irq(phy) != 0)
 		return IRQ_NONE;
 
-	tasklet_schedule(&phy->vchan->tasklet);
+	dma_chan_schedule_bh(&phy->vchan->chan);
 	return IRQ_HANDLED;
 }
 

@@ -1047,13 +1046,11 @@ static void mmp_pdma_issue_pending(struct dma_chan *dchan)
 }
 
 /*
- * dma_do_tasklet
- * Do call back
- * Start pending list
+ * dma_do_tasklet - BH worker to process completions and kick pending work
  */
-static void dma_do_tasklet(struct tasklet_struct *t)
+static void dma_do_tasklet(struct dma_chan *c)
 {
-	struct mmp_pdma_chan *chan = from_tasklet(chan, t, tasklet);
+	struct mmp_pdma_chan *chan = container_of(c, struct mmp_pdma_chan, chan);
 	struct mmp_pdma_desc_sw *desc, *_desc;
 	LIST_HEAD(chain_cleanup);
 	unsigned long flags;

@@ -1170,7 +1167,7 @@ static int mmp_pdma_chan_init(struct mmp_pdma_device *pdev, int idx, int irq)
 	spin_lock_init(&chan->desc_lock);
 	chan->dev = pdev->dev;
 	chan->chan.device = &pdev->device;
-	tasklet_setup(&chan->tasklet, dma_do_tasklet);
+	dma_chan_init_bh(&chan->chan, dma_do_tasklet);
 	INIT_LIST_HEAD(&chan->chain_pending);
 	INIT_LIST_HEAD(&chan->chain_running);
 

index ba03321eeff7..d1ed2886f0e7 100644
@@ -102,7 +102,6 @@ struct mmp_tdma_chan {
 	struct device			*dev;
 	struct dma_chan			chan;
 	struct dma_async_tx_descriptor	desc;
-	struct tasklet_struct		tasklet;
 
 	struct mmp_tdma_desc		*desc_arr;
 	dma_addr_t			desc_arr_phys;

@@ -320,7 +319,7 @@ static irqreturn_t mmp_tdma_chan_handler(int irq, void *dev_id)
 	struct mmp_tdma_chan *tdmac = dev_id;
 
 	if (mmp_tdma_clear_chan_irq(tdmac) == 0) {
-		tasklet_schedule(&tdmac->tasklet);
+		dma_chan_schedule_bh(&tdmac->chan);
 		return IRQ_HANDLED;
 	} else
 		return IRQ_NONE;

@@ -346,9 +345,9 @@ static irqreturn_t mmp_tdma_int_handler(int irq, void *dev_id)
 		return IRQ_NONE;
 }
 
-static void dma_do_tasklet(struct tasklet_struct *t)
+static void dma_do_tasklet(struct dma_chan *c)
 {
-	struct mmp_tdma_chan *tdmac = from_tasklet(tdmac, t, tasklet);
+	struct mmp_tdma_chan *tdmac = container_of(c, struct mmp_tdma_chan, chan);
 
 	dmaengine_desc_get_callback_invoke(&tdmac->desc, NULL);
 }

@@ -583,7 +582,7 @@ static int mmp_tdma_chan_init(struct mmp_tdma_device *tdev,
 	tdmac->pool	   = pool;
 	tdmac->status = DMA_COMPLETE;
 	tdev->tdmac[tdmac->idx] = tdmac;
-	tasklet_setup(&tdmac->tasklet, dma_do_tasklet);
+	dma_chan_init_bh(&tdmac->chan, dma_do_tasklet);
 
 	/* add the channel to tdma_chan list */
 	list_add_tail(&tdmac->chan.device_node,

index 25ed61f1b089..3a70d565e1ef 100644
@@ -327,7 +327,7 @@ static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan)
 				 * some descriptors are still waiting
 				 * to be cleaned
 				 */
-				tasklet_schedule(&mv_chan->irq_tasklet);
+				dma_chan_schedule_bh(&mv_chan->dmachan);
 			}
 		}
 	}

@@ -336,9 +336,9 @@ static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan)
 		mv_chan->dmachan.completed_cookie = cookie;
 }
 
-static void mv_xor_tasklet(struct tasklet_struct *t)
+static void mv_xor_tasklet(struct dma_chan *c)
 {
-	struct mv_xor_chan *chan = from_tasklet(chan, t, irq_tasklet);
+	struct mv_xor_chan *chan = to_mv_xor_chan(c);
 
 	spin_lock(&chan->lock);
 	mv_chan_slot_cleanup(chan);

@@ -372,7 +372,7 @@ mv_chan_alloc_slot(struct mv_xor_chan *mv_chan)
 	spin_unlock_bh(&mv_chan->lock);
 
 	/* try to free some slots if the allocation fails */
-	tasklet_schedule(&mv_chan->irq_tasklet);
+	dma_chan_schedule_bh(&mv_chan->dmachan);
 
 	return NULL;
 }

@@ -737,7 +737,7 @@ static irqreturn_t mv_xor_interrupt_handler(int irq, void *data)
 	if (intr_cause & XOR_INTR_ERRORS)
 		mv_chan_err_interrupt_handler(chan, intr_cause);
 
-	tasklet_schedule(&chan->irq_tasklet);
+	dma_chan_schedule_bh(&chan->dmachan);
 
 	mv_chan_clear_eoc_cause(chan);
 

@@ -1107,7 +1107,7 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 
 	mv_chan->mmr_base = xordev->xor_base;
 	mv_chan->mmr_high_base = xordev->xor_high_base;
-	tasklet_setup(&mv_chan->irq_tasklet, mv_xor_tasklet);
+	dma_chan_init_bh(&mv_chan->dmachan, mv_xor_tasklet);
 
 	/* clear errors before enabling interrupts */
 	mv_chan_clear_err_status(mv_chan);

index c87cefd38a07..27774abe34a6 100644
@@ -98,7 +98,6 @@ struct mv_xor_device {
  * @device: parent device
  * @common: common dmaengine channel object members
  * @slots_allocated: records the actual size of the descriptor slot pool
- * @irq_tasklet: bottom half where mv_xor_slot_cleanup runs
  * @op_in_desc: new mode of driver, each op is written to descriptor.
  */
 struct mv_xor_chan {

@@ -118,7 +117,6 @@ struct mv_xor_chan {
 	struct dma_device	dmadev;
 	struct dma_chan		dmachan;
 	int			slots_allocated;
-	struct tasklet_struct	irq_tasklet;
 	int                     op_in_desc;
 	char			dummy_src[MV_XOR_MIN_BYTE_COUNT];
 	char			dummy_dst[MV_XOR_MIN_BYTE_COUNT];

index 7acb3d29dad3..8cecc0add82d 100644
@@ -109,7 +109,6 @@ struct mxs_dma_chan {
 	struct mxs_dma_engine		*mxs_dma;
 	struct dma_chan			chan;
 	struct dma_async_tx_descriptor	desc;
-	struct tasklet_struct		tasklet;
 	unsigned int			chan_irq;
 	struct mxs_dma_ccw		*ccw;
 	dma_addr_t			ccw_phys;

@@ -300,9 +299,9 @@ static dma_cookie_t mxs_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 	return dma_cookie_assign(tx);
 }
 
-static void mxs_dma_tasklet(struct tasklet_struct *t)
+static void mxs_dma_tasklet(struct dma_chan *chan)
 {
-	struct mxs_dma_chan *mxs_chan = from_tasklet(mxs_chan, t, tasklet);
+	struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
 
 	dmaengine_desc_get_callback_invoke(&mxs_chan->desc, NULL);
 }

@@ -386,8 +385,8 @@ static irqreturn_t mxs_dma_int_handler(int irq, void *dev_id)
 		dma_cookie_complete(&mxs_chan->desc);
 	}
 
-	/* schedule tasklet on this channel */
-	tasklet_schedule(&mxs_chan->tasklet);
+	/* schedule BH on this channel */
+	dma_chan_schedule_bh(&mxs_chan->chan);
 
 	return IRQ_HANDLED;
 }

@@ -781,7 +780,7 @@ static int mxs_dma_probe(struct platform_device *pdev)
 		mxs_chan->chan.device = &mxs_dma->dma_device;
 		dma_cookie_init(&mxs_chan->chan);
 
-		tasklet_setup(&mxs_chan->tasklet, mxs_dma_tasklet);
+		dma_chan_init_bh(&mxs_chan->chan, mxs_dma_tasklet);
 
 
 		/* Add the channel to mxs_chan list */

index 05d7321629cc..aea94451258a 100644
@@ -174,7 +174,6 @@ struct nbpf_desc_page {
 /**
  * struct nbpf_channel - one DMAC channel
  * @dma_chan:	standard dmaengine channel object
- * @tasklet:	channel specific tasklet used for callbacks
  * @base:	register address base
  * @nbpf:	DMAC
  * @name:	IRQ name

@@ -200,7 +199,6 @@ struct nbpf_desc_page {
  */
 struct nbpf_channel {
 	struct dma_chan dma_chan;
-	struct tasklet_struct tasklet;
 	void __iomem *base;
 	struct nbpf_device *nbpf;
 	char name[16];

@@ -1125,9 +1123,10 @@ static struct dma_chan *nbpf_of_xlate(struct of_phandle_args *dma_spec,
 	return dchan;
 }
 
-static void nbpf_chan_tasklet(struct tasklet_struct *t)
+static void nbpf_chan_tasklet(struct dma_chan *c)
 {
-	struct nbpf_channel *chan = from_tasklet(chan, t, tasklet);
+	struct nbpf_channel *chan = container_of(c, struct nbpf_channel,
+						 dma_chan);
 	struct nbpf_desc *desc, *tmp;
 	struct dmaengine_desc_callback cb;
 

@@ -1228,7 +1227,7 @@ static irqreturn_t nbpf_chan_irq(int irq, void *dev)
 	spin_unlock(&chan->lock);
 
 	if (bh)
-		tasklet_schedule(&chan->tasklet);
+		dma_chan_schedule_bh(&chan->dma_chan);
 
 	return ret;
 }

@@ -1272,7 +1271,7 @@ static int nbpf_chan_probe(struct nbpf_device *nbpf, int n)
 
 	snprintf(chan->name, sizeof(chan->name), "nbpf %d", n);
 
-	tasklet_setup(&chan->tasklet, nbpf_chan_tasklet);
+	dma_chan_init_bh(&chan->dma_chan, nbpf_chan_tasklet);
 	ret = devm_request_irq(dma_dev->dev, chan->irq,
 			nbpf_chan_irq, IRQF_SHARED,
 			chan->name, chan);

@@ -1478,7 +1477,7 @@ static void nbpf_remove(struct platform_device *pdev)
 
 		devm_free_irq(&pdev->dev, chan->irq, chan);
 
-		tasklet_kill(&chan->tasklet);
+		dma_chan_kill_bh(&chan->dma_chan);
 	}
 
 	of_dma_controller_free(pdev->dev.of_node);

index bf805f1024f6..b0044bea8fe4 100644
@@ -91,7 +91,6 @@ struct pch_dma_chan {
 	struct dma_chan		chan;
 	void __iomem *membase;
 	enum dma_transfer_direction dir;
-	struct tasklet_struct	tasklet;
 	unsigned long		err_status;
 
 	spinlock_t		lock;

@@ -665,9 +664,10 @@ static int pd_device_terminate_all(struct dma_chan *chan)
 	return 0;
 }
 
-static void pdc_tasklet(struct tasklet_struct *t)
+static void pdc_tasklet(struct dma_chan *c)
 {
-	struct pch_dma_chan *pd_chan = from_tasklet(pd_chan, t, tasklet);
+	struct pch_dma_chan *pd_chan = container_of(c, struct pch_dma_chan,
+						    chan);
 	unsigned long flags;
 
 	if (!pdc_is_idle(pd_chan)) {

@@ -707,7 +707,7 @@ static irqreturn_t pd_irq(int irq, void *devid)
 				if (sts0 & DMA_STATUS0_ERR(i))
 					set_bit(0, &pd_chan->err_status);
 
-				tasklet_schedule(&pd_chan->tasklet);
+				dma_chan_schedule_bh(&pd_chan->chan);
 				ret0 = IRQ_HANDLED;
 			}
 		} else {

@@ -715,7 +715,7 @@ static irqreturn_t pd_irq(int irq, void *devid)
 				if (sts2 & DMA_STATUS2_ERR(i))
 					set_bit(0, &pd_chan->err_status);
 
-				tasklet_schedule(&pd_chan->tasklet);
+				dma_chan_schedule_bh(&pd_chan->chan);
 				ret2 = IRQ_HANDLED;
 			}
 		}

@@ -877,7 +877,7 @@ static int pch_dma_probe(struct pci_dev *pdev,
 		INIT_LIST_HEAD(&pd_chan->queue);
 		INIT_LIST_HEAD(&pd_chan->free_list);
 
-		tasklet_setup(&pd_chan->tasklet, pdc_tasklet);
+		dma_chan_init_bh(&pd_chan->chan, pdc_tasklet);
 		list_add_tail(&pd_chan->chan.device_node, &pd->dma.channels);
 	}
 

@@ -930,7 +930,7 @@ static void pch_dma_remove(struct pci_dev *pdev)
 					 device_node) {
 			pd_chan = to_pd_chan(chan);
 
-			tasklet_kill(&pd_chan->tasklet);
+			dma_chan_kill_bh(&pd_chan->chan);
 		}
 
 		dma_pool_destroy(pd->pool);

index 279a431ccae3..98cfd012ca5b 100644
@@ -1658,9 +1658,9 @@ static void __ppc440spe_adma_slot_cleanup(struct ppc440spe_adma_chan *chan)
 /**
  * ppc440spe_adma_tasklet - clean up watch-dog initiator
  */
-static void ppc440spe_adma_tasklet(struct tasklet_struct *t)
+static void ppc440spe_adma_tasklet(struct dma_chan *c)
 {
-	struct ppc440spe_adma_chan *chan = from_tasklet(chan, t, irq_tasklet);
+	struct ppc440spe_adma_chan *chan = to_ppc440spe_adma_chan(c);
 
 	spin_lock_nested(&chan->lock, SINGLE_DEPTH_NESTING);
 	__ppc440spe_adma_slot_cleanup(chan);

@@ -1754,7 +1754,7 @@ static struct ppc440spe_adma_desc_slot *ppc440spe_adma_alloc_slots(
 		goto retry;
 
 	/* try to free some slots if the allocation fails */
-	tasklet_schedule(&chan->irq_tasklet);
+	dma_chan_schedule_bh(&chan->common);
 	return NULL;
 }
 

@@ -3595,7 +3595,7 @@ static irqreturn_t ppc440spe_adma_eot_handler(int irq, void *data)
 	dev_dbg(chan->device->common.dev,
 		"ppc440spe adma%d: %s\n", chan->device->id, __func__);
 
-	tasklet_schedule(&chan->irq_tasklet);
+	dma_chan_schedule_bh(&chan->common);
 	ppc440spe_adma_device_clear_eot_status(chan);
 
 	return IRQ_HANDLED;

@@ -3612,7 +3612,7 @@ static irqreturn_t ppc440spe_adma_err_handler(int irq, void *data)
 	dev_dbg(chan->device->common.dev,
 		"ppc440spe adma%d: %s\n", chan->device->id, __func__);
 
-	tasklet_schedule(&chan->irq_tasklet);
+	dma_chan_schedule_bh(&chan->common);
 	ppc440spe_adma_device_clear_eot_status(chan);
 
 	return IRQ_HANDLED;

@@ -4137,7 +4137,7 @@ static int ppc440spe_adma_probe(struct platform_device *ofdev)
 	chan->common.device = &adev->common;
 	dma_cookie_init(&chan->common);
 	list_add_tail(&chan->common.device_node, &adev->common.channels);
-	tasklet_setup(&chan->irq_tasklet, ppc440spe_adma_tasklet);
+	dma_chan_init_bh(&chan->common, ppc440spe_adma_tasklet);
 
 	/* allocate and map helper pages for async validation or
 	 * async_mult/async_sum_product operations on DMA0/1.

@@ -4247,7 +4247,7 @@ static void ppc440spe_adma_remove(struct platform_device *ofdev)
 				 device_node) {
 		ppc440spe_chan = to_ppc440spe_adma_chan(chan);
 		ppc440spe_adma_release_irqs(adev, ppc440spe_chan);
-		tasklet_kill(&ppc440spe_chan->irq_tasklet);
+		dma_chan_kill_bh(&ppc440spe_chan->common);
 		if (adev->id != PPC440SPE_XOR_ID) {
 			dma_unmap_page(&ofdev->dev, ppc440spe_chan->pdest,
 					PAGE_SIZE, DMA_BIDIRECTIONAL);

index f8a5d7c1fb40..9af1feaf0b9a 100644
@@ -80,7 +80,6 @@ struct ppc440spe_adma_device {
  * @pending: allows batching of hardware operations
  * @slots_allocated: records the actual size of the descriptor slot pool
  * @hw_chain_inited: h/w descriptor chain initialization flag
- * @irq_tasklet: bottom half where ppc440spe_adma_slot_cleanup runs
  * @needs_unmap: if buffers should not be unmapped upon final processing
  * @pdest_page: P destination page for async validate operation
  * @qdest_page: Q destination page for async validate operation

@@ -97,7 +96,6 @@ struct ppc440spe_adma_chan {
 	int pending;
 	int slots_allocated;
 	int hw_chain_inited;
-	struct tasklet_struct irq_tasklet;
 	u8 needs_unmap;
 	struct page *pdest_page;
 	struct page *qdest_page;

index 0d9ffa3e2663..f279a093a81f 100644
@@ -461,8 +461,6 @@ struct d40_base;
  * @phy_chan: Pointer to physical channel which this instance runs on. If this
  * point is NULL, then the channel is not allocated.
  * @chan: DMA engine handle.
- * @tasklet: Tasklet that gets scheduled from interrupt context to complete a
- * transfer and call client callback.
  * @client: Cliented owned descriptor list.
  * @pending_queue: Submitted jobs, to be issued by issue_pending()
  * @active: Active descriptor.

@@ -489,7 +487,6 @@ struct d40_chan {
 	bool				 busy;
 	struct d40_phy_res		*phy_chan;
 	struct dma_chan			 chan;
-	struct tasklet_struct		 tasklet;
 	struct list_head		 client;
 	struct list_head		 pending_queue;
 	struct list_head		 active;

@@ -1587,13 +1584,13 @@ static void dma_tc_handle(struct d40_chan *d40c)
 	}
 
 	d40c->pending_tx++;
-	tasklet_schedule(&d40c->tasklet);
+	dma_chan_schedule_bh(&d40c->chan);
 
 }
 
-static void dma_tasklet(struct tasklet_struct *t)
+static void dma_tasklet(struct dma_chan *chan)
 {
-	struct d40_chan *d40c = from_tasklet(d40c, t, tasklet);
+	struct d40_chan *d40c = container_of(chan, struct d40_chan, chan);
 	struct d40_desc *d40d;
 	unsigned long flags;
 	bool callback_active;

@@ -1641,7 +1638,7 @@ static void dma_tasklet(struct tasklet_struct *t)
 	d40c->pending_tx--;
 
 	if (d40c->pending_tx)
-		tasklet_schedule(&d40c->tasklet);
+		dma_chan_schedule_bh(&d40c->chan);
 
 	spin_unlock_irqrestore(&d40c->lock, flags);
 

@@ -2815,7 +2812,7 @@ static void __init d40_chan_init(struct d40_base *base, struct dma_device *dma,
 		INIT_LIST_HEAD(&d40c->client);
 		INIT_LIST_HEAD(&d40c->prepare_queue);
 
-		tasklet_setup(&d40c->tasklet, dma_tasklet);
+		dma_chan_init_bh(&d40c->chan, dma_tasklet);
 
 		list_add_tail(&d40c->chan.device_node,
 			      &dma->channels);