[PATCH v7 7/9] nvmet: pci-epf: Use dmaengine_prep_config_single_safe() API

[Frank.Li at oss.nxp.com]

From: Frank Li <Frank.Li at nxp.com>

Use the new dmaengine_prep_config_single_safe() API to combine the
configuration and descriptor preparation into a single call.

Since dmaengine_prep_config_single_safe() performs the configuration and
preparation atomically and the mutex can be removed.

Tested-by: Niklas Cassel <cassel at kernel.org>
Acked-by: Manivannan Sadhasivam <mani at kernel.org>
Signed-off-by: Frank Li <Frank.Li at nxp.com>
---
change in v7
- remove dma_(rx|tx)_lock totally (sashika AI)
change in v6
- remove local unused variable lock (sashika AI)
---
 drivers/nvme/target/pci-epf.c | 30 ++++--------------------------
 1 file changed, 4 insertions(+), 26 deletions(-)

diff --git a/drivers/nvme/target/pci-epf.c b/drivers/nvme/target/pci-epf.c
index 2afe8f4d0e461..b1ba2d0bea6d9 100644
--- a/drivers/nvme/target/pci-epf.c
+++ b/drivers/nvme/target/pci-epf.c
@@ -210,9 +210,7 @@ struct nvmet_pci_epf {
 
 	bool				dma_enabled;
 	struct dma_chan			*dma_tx_chan;
-	struct mutex			dma_tx_lock;
 	struct dma_chan			*dma_rx_chan;
-	struct mutex			dma_rx_lock;
 
 	struct mutex			mmio_lock;
 
@@ -295,9 +293,6 @@ static void nvmet_pci_epf_init_dma(struct nvmet_pci_epf *nvme_epf)
 	struct dma_chan *chan;
 	dma_cap_mask_t mask;
 
-	mutex_init(&nvme_epf->dma_rx_lock);
-	mutex_init(&nvme_epf->dma_tx_lock);
-
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
 
@@ -336,8 +331,6 @@ static void nvmet_pci_epf_init_dma(struct nvmet_pci_epf *nvme_epf)
 	nvme_epf->dma_rx_chan = NULL;
 
 out_dma_no_rx:
-	mutex_destroy(&nvme_epf->dma_rx_lock);
-	mutex_destroy(&nvme_epf->dma_tx_lock);
 	nvme_epf->dma_enabled = false;
 
 	dev_info(&epf->dev, "DMA not supported, falling back to MMIO\n");
@@ -352,8 +345,6 @@ static void nvmet_pci_epf_deinit_dma(struct nvmet_pci_epf *nvme_epf)
 	nvme_epf->dma_tx_chan = NULL;
 	dma_release_channel(nvme_epf->dma_rx_chan);
 	nvme_epf->dma_rx_chan = NULL;
-	mutex_destroy(&nvme_epf->dma_rx_lock);
-	mutex_destroy(&nvme_epf->dma_tx_lock);
 	nvme_epf->dma_enabled = false;
 }
 
@@ -368,18 +359,15 @@ static int nvmet_pci_epf_dma_transfer(struct nvmet_pci_epf *nvme_epf,
 	struct dma_chan *chan;
 	dma_cookie_t cookie;
 	dma_addr_t dma_addr;
-	struct mutex *lock;
 	int ret;
 
 	switch (dir) {
 	case DMA_FROM_DEVICE:
-		lock = &nvme_epf->dma_rx_lock;
 		chan = nvme_epf->dma_rx_chan;
 		sconf.direction = DMA_DEV_TO_MEM;
 		sconf.src_addr = seg->pci_addr;
 		break;
 	case DMA_TO_DEVICE:
-		lock = &nvme_epf->dma_tx_lock;
 		chan = nvme_epf->dma_tx_chan;
 		sconf.direction = DMA_MEM_TO_DEV;
 		sconf.dst_addr = seg->pci_addr;
@@ -388,22 +376,15 @@ static int nvmet_pci_epf_dma_transfer(struct nvmet_pci_epf *nvme_epf,
 		return -EINVAL;
 	}
 
-	mutex_lock(lock);
-
 	dma_dev = dmaengine_get_dma_device(chan);
 	dma_addr = dma_map_single(dma_dev, seg->buf, seg->length, dir);
 	ret = dma_mapping_error(dma_dev, dma_addr);
 	if (ret)
-		goto unlock;
-
-	ret = dmaengine_slave_config(chan, &sconf);
-	if (ret) {
-		dev_err(dev, "Failed to configure DMA channel\n");
-		goto unmap;
-	}
+		return ret;
 
-	desc = dmaengine_prep_slave_single(chan, dma_addr, seg->length,
-					   sconf.direction, DMA_CTRL_ACK);
+	desc = dmaengine_prep_config_single_safe(chan, dma_addr, seg->length,
+						 sconf.direction,
+						 DMA_CTRL_ACK, &sconf);
 	if (!desc) {
 		dev_err(dev, "Failed to prepare DMA\n");
 		ret = -EIO;
@@ -426,9 +407,6 @@ static int nvmet_pci_epf_dma_transfer(struct nvmet_pci_epf *nvme_epf,
 unmap:
 	dma_unmap_single(dma_dev, dma_addr, seg->length, dir);
 
-unlock:
-	mutex_unlock(lock);
-
 	return ret;
 }
 

-- 
2.43.0