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Message-ID: <20260108080332.2341725-2-allen.lkml@gmail.com>
Date: Thu, 8 Jan 2026 00:03:31 -0800
From: Allen Pais <allen.lkml@...il.com>
To: vkoul@...nel.org
Cc: arnd@...db.de,
kees@...nel.org,
dmaengine@...r.kernel.org,
linux-kernel@...r.kernel.org,
Allen Pais <allen.lkml@...il.com>
Subject: [RFC PATCH 1/1] dmaengine: introduce dmaengine_bh_wq and bh helpers
Create a dedicated dmaengine bottom-half workqueue (WQ_BH | WQ_PERCPU)
and provide helper APIs for queue/flush/cancel of BH work items. Add
per-channel BH helpers in dma_chan so drivers can schedule a BH callback
without maintaining their own tasklets.
Convert virt-dma to use the new per-channel BH helpers and remove the
per-channel tasklet. Update existing drivers that only need tasklet
teardown to use dma_chan_kill_bh().
This provides a common BH execution path for dmaengine and establishes
the base for converting remaining DMA tasklets to workqueue-based BHs.
Signed-off-by: Allen Pais <allen.lkml@...il.com>
---
drivers/dma/amd/qdma/qdma.c | 1 +
drivers/dma/bcm2835-dma.c | 2 +-
drivers/dma/dmaengine.c | 109 +++++++++++++++++-
.../dma/dw-axi-dmac/dw-axi-dmac-platform.c | 2 +-
drivers/dma/dw-edma/dw-edma-core.c | 2 +-
drivers/dma/hisi_dma.c | 2 +-
drivers/dma/img-mdc-dma.c | 2 +-
drivers/dma/imx-sdma.c | 2 +-
drivers/dma/k3dma.c | 2 +-
drivers/dma/loongson1-apb-dma.c | 2 +-
drivers/dma/mediatek/mtk-cqdma.c | 2 +-
drivers/dma/mediatek/mtk-hsdma.c | 2 +-
drivers/dma/mediatek/mtk-uart-apdma.c | 4 +-
drivers/dma/owl-dma.c | 2 +-
drivers/dma/pxa_dma.c | 2 +-
drivers/dma/qcom/bam_dma.c | 4 +-
drivers/dma/qcom/qcom_adm.c | 2 +-
drivers/dma/sa11x0-dma.c | 2 +-
drivers/dma/sprd-dma.c | 2 +-
drivers/dma/sun6i-dma.c | 2 +-
drivers/dma/tegra186-gpc-dma.c | 2 +-
drivers/dma/tegra210-adma.c | 2 +-
drivers/dma/ti/k3-udma.c | 8 +-
drivers/dma/ti/omap-dma.c | 2 +-
drivers/dma/virt-dma.c | 6 +-
drivers/dma/virt-dma.h | 8 +-
include/linux/dmaengine.h | 50 ++++++++
27 files changed, 189 insertions(+), 39 deletions(-)
diff --git a/drivers/dma/amd/qdma/qdma.c b/drivers/dma/amd/qdma/qdma.c
index 8fb2d5e1df20..b57f8ebf2446 100644
--- a/drivers/dma/amd/qdma/qdma.c
+++ b/drivers/dma/amd/qdma/qdma.c
@@ -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"
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 321748e2983e..08a206cfbb76 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -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,
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ca13cd39330b..d3df4e943d37 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -54,6 +54,7 @@
#include <linux/of_dma.h>
#include <linux/mempool.h>
#include <linux/numa.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
@@ -1425,6 +1427,92 @@ static void dmaengine_destroy_unmap_pool(void)
}
}
+static void dmaengine_destroy_bh_wq(void)
+{
+ if (!dmaengine_bh_wq)
+ return;
+
+ destroy_workqueue(dmaengine_bh_wq);
+ dmaengine_bh_wq = NULL;
+}
+
+bool dmaengine_queue_bh_work(struct work_struct *work)
+{
+ if (WARN_ON(!dmaengine_bh_wq))
+ return false;
+
+ return queue_work(dmaengine_bh_wq, work);
+}
+EXPORT_SYMBOL_GPL(dmaengine_queue_bh_work);
+
+void dmaengine_flush_bh_work(struct work_struct *work)
+{
+ if (!work)
+ return;
+
+ flush_work(work);
+}
+EXPORT_SYMBOL_GPL(dmaengine_flush_bh_work);
+
+void dmaengine_cancel_bh_work_sync(struct work_struct *work)
+{
+ if (!work)
+ return;
+
+ cancel_work_sync(work);
+}
+EXPORT_SYMBOL_GPL(dmaengine_cancel_bh_work_sync);
+
+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)
+ 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;
+ INIT_WORK(&chan->bh_work, 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;
+
+ return dmaengine_queue_bh_work(&chan->bh_work);
+}
+EXPORT_SYMBOL_GPL(dma_chan_schedule_bh);
+
+void dma_chan_flush_bh(struct dma_chan *chan)
+{
+ if (!chan->bh_work_initialized)
+ return;
+
+ dmaengine_flush_bh_work(&chan->bh_work);
+}
+EXPORT_SYMBOL_GPL(dma_chan_flush_bh);
+
+void dma_chan_kill_bh(struct dma_chan *chan)
+{
+ if (!chan->bh_work_initialized)
+ return;
+
+ dmaengine_cancel_bh_work_sync(&chan->bh_work);
+}
+EXPORT_SYMBOL_GPL(dma_chan_kill_bh);
+
static int __init dmaengine_init_unmap_pool(void)
{
int i;
@@ -1621,15 +1709,28 @@ 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);
diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
index b23536645ff7..42018b21d2ab 100644
--- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
+++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
@@ -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);
}
}
diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
index 8e5f7defa6b6..378650bcc430 100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -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);
}
diff --git a/drivers/dma/hisi_dma.c b/drivers/dma/hisi_dma.c
index 25a4134be36b..a15491945329 100644
--- a/drivers/dma/hisi_dma.c
+++ b/drivers/dma/hisi_dma.c
@@ -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);
}
}
diff --git a/drivers/dma/img-mdc-dma.c b/drivers/dma/img-mdc-dma.c
index fd55bcd060ab..d4f6d839acca 100644
--- a/drivers/dma/img-mdc-dma.c
+++ b/drivers/dma/img-mdc-dma.c
@@ -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);
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index ed9e56de5a9b..9cbc95fbb4ee 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -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);
}
diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
index 0f9cd7815f88..36d5df545b57 100644
--- a/drivers/dma/k3dma.c
+++ b/drivers/dma/k3dma.c
@@ -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);
diff --git a/drivers/dma/loongson1-apb-dma.c b/drivers/dma/loongson1-apb-dma.c
index 255fe7eca212..49a78ea1514f 100644
--- a/drivers/dma/loongson1-apb-dma.c
+++ b/drivers/dma/loongson1-apb-dma.c
@@ -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);
}
}
}
diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
index 9f0c41ca7770..3ba54df12bae 100644
--- a/drivers/dma/mediatek/mtk-cqdma.c
+++ b/drivers/dma/mediatek/mtk-cqdma.c
@@ -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 */
diff --git a/drivers/dma/mediatek/mtk-hsdma.c b/drivers/dma/mediatek/mtk-hsdma.c
index fa77bb24a430..0bbf865de24b 100644
--- a/drivers/dma/mediatek/mtk-hsdma.c
+++ b/drivers/dma/mediatek/mtk-hsdma.c
@@ -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 */
diff --git a/drivers/dma/mediatek/mtk-uart-apdma.c b/drivers/dma/mediatek/mtk-uart-apdma.c
index 08e15177427b..257b9b77cc57 100644
--- a/drivers/dma/mediatek/mtk-uart-apdma.c
+++ b/drivers/dma/mediatek/mtk-uart-apdma.c
@@ -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);
}
}
diff --git a/drivers/dma/owl-dma.c b/drivers/dma/owl-dma.c
index 57cec757d8f5..4e6ebf990688 100644
--- a/drivers/dma/owl-dma.c
+++ b/drivers/dma/owl-dma.c
@@ -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);
}
}
diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index 249296389771..634b723e4891 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -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);
}
}
diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 2cf060174795..6ec82adb89ce 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -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;
diff --git a/drivers/dma/qcom/qcom_adm.c b/drivers/dma/qcom/qcom_adm.c
index 6be54fddcee1..0f9e906bd463 100644
--- a/drivers/dma/qcom/qcom_adm.c
+++ b/drivers/dma/qcom/qcom_adm.c
@@ -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);
}
diff --git a/drivers/dma/sa11x0-dma.c b/drivers/dma/sa11x0-dma.c
index dc1a9a05252e..42940079efbf 100644
--- a/drivers/dma/sa11x0-dma.c
+++ b/drivers/dma/sa11x0-dma.c
@@ -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);
}
}
diff --git a/drivers/dma/sprd-dma.c b/drivers/dma/sprd-dma.c
index 6207e0b185e1..5124fe0a93bf 100644
--- a/drivers/dma/sprd-dma.c
+++ b/drivers/dma/sprd-dma.c
@@ -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);
diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
index 2215ff877bf7..6b3ab99272a5 100644
--- a/drivers/dma/sun6i-dma.c
+++ b/drivers/dma/sun6i-dma.c
@@ -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);
}
}
diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
index 4d6fe0efa76e..3b9dc64eb635 100644
--- a/drivers/dma/tegra186-gpc-dma.c
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -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;
diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
index d0e8bb27a03b..67ccb1d48361 100644
--- a/drivers/dma/tegra210-adma.c
+++ b/drivers/dma/tegra210-adma.c
@@ -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));
diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index aa2dc762140f..89dd7926705d 100644
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -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);
}
diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
index 8c023c6e623a..f6aee92071e2 100644
--- a/drivers/dma/ti/omap-dma.c
+++ b/drivers/dma/ti/omap-dma.c
@@ -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);
}
}
diff --git a/drivers/dma/virt-dma.c b/drivers/dma/virt-dma.c
index 7961172a780d..c311397f3bd7 100644
--- a/drivers/dma/virt-dma.c
+++ b/drivers/dma/virt-dma.c
@@ -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);
diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h
index 59d9eabc8b67..5299fb7367ca 100644
--- a/drivers/dma/virt-dma.h
+++ b/drivers/dma/virt-dma.h
@@ -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);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 99efe2b9b4ea..00ad92a73c3b 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -12,6 +12,7 @@
#include <linux/scatterlist.h>
#include <linux/bitmap.h>
#include <linux/types.h>
+#include <linux/workqueue.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_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;
@@ -359,6 +367,9 @@ struct dma_chan {
void *route_data;
void *private;
+ struct work_struct bh_work;
+ dma_chan_bh_work_fn bh_work_fn;
+ bool bh_work_initialized;
};
/**
@@ -1528,6 +1539,14 @@ 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);
+bool dmaengine_queue_bh_work(struct work_struct *work);
+void dmaengine_flush_bh_work(struct work_struct *work);
+void dmaengine_cancel_bh_work_sync(struct work_struct *work);
+
+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_flush_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)
{
@@ -1575,6 +1594,37 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
{
return -ENXIO;
}
+
+static inline bool dmaengine_queue_bh_work(struct work_struct *work)
+{
+ return false;
+}
+
+static inline void dmaengine_flush_bh_work(struct work_struct *work)
+{
+}
+
+static inline void dmaengine_cancel_bh_work_sync(struct work_struct *work)
+{
+}
+
+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_flush_bh(struct dma_chan *chan)
+{
+}
+
+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)
--
2.43.0
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