linux-kernel - [PATCH v2] scsi: ibmvscsi: Use dma_alloc_noncoherent() instead of get_zeroed_page/dma_map

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Message-ID: <20211012032317.2360-1-caihuoqing@baidu.com>
Date:   Tue, 12 Oct 2021 11:23:16 +0800
From:   Cai Huoqing <caihuoqing@...du.com>
To:     <caihuoqing@...du.com>
CC:     Tyrel Datwyler <tyreld@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        "Paul Mackerras" <paulus@...ba.org>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        <linux-scsi@...r.kernel.org>, <linuxppc-dev@...ts.ozlabs.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] scsi: ibmvscsi: Use dma_alloc_noncoherent() instead of get_zeroed_page/dma_map_single()

Replacing get_zeroed_page/free_page/dma_map_single/dma_unmap_single()
with dma_alloc_noncoherent/dma_free_noncoherent() helps to reduce
code size, and simplify the code, and the hardware can keeep DMA
coherent itself.

Signed-off-by: Cai Huoqing <caihuoqing@...du.com>
---
v1->v2:
	*Change to dma_alloc/free_noncoherent from dma_alloc/free_coherent.
	*Update changelog.

 drivers/scsi/ibmvscsi/ibmvfc.c   | 16 ++++------------
 drivers/scsi/ibmvscsi/ibmvscsi.c | 29 +++++++++--------------------
 2 files changed, 13 insertions(+), 32 deletions(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 1f1586ad48fe..6e95fd02fd25 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -869,8 +869,8 @@ static void ibmvfc_free_queue(struct ibmvfc_host *vhost,
 {
 	struct device *dev = vhost->dev;
 
-	dma_unmap_single(dev, queue->msg_token, PAGE_SIZE, DMA_BIDIRECTIONAL);
-	free_page((unsigned long)queue->msgs.handle);
+	dma_free_noncoherent(dev, PAGE_SIZE, queue->msgs.handle,
+			     queue->msg_token, DMA_BIDIRECTIONAL);
 	queue->msgs.handle = NULL;
 
 	ibmvfc_free_event_pool(vhost, queue);
@@ -5663,19 +5663,11 @@ static int ibmvfc_alloc_queue(struct ibmvfc_host *vhost,
 		return -ENOMEM;
 	}
 
-	queue->msgs.handle = (void *)get_zeroed_page(GFP_KERNEL);
+	queue->msgs.handle = dma_alloc_noncoherent(dev, PAGE_SIZE, &queue->msg_token,
+						   DMA_BIDIRECTIONAL, GFP_KERNEL);
 	if (!queue->msgs.handle)
 		return -ENOMEM;
 
-	queue->msg_token = dma_map_single(dev, queue->msgs.handle, PAGE_SIZE,
-					  DMA_BIDIRECTIONAL);
-
-	if (dma_mapping_error(dev, queue->msg_token)) {
-		free_page((unsigned long)queue->msgs.handle);
-		queue->msgs.handle = NULL;
-		return -ENOMEM;
-	}
-
 	queue->cur = 0;
 	queue->fmt = fmt;
 	queue->size = PAGE_SIZE / fmt_size;
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index ea8e01f49cba..68409c298c74 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -151,10 +151,8 @@ static void ibmvscsi_release_crq_queue(struct crq_queue *queue,
 			msleep(100);
 		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
 	} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
-	dma_unmap_single(hostdata->dev,
-			 queue->msg_token,
-			 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
-	free_page((unsigned long)queue->msgs);
+	dma_free_noncoherent(hostdata->dev, PAGE_SIZE,
+			     queue->msgs, queue->msg_token, DMA_BIDIRECTIONAL);
 }
 
 /**
@@ -331,18 +329,12 @@ static int ibmvscsi_init_crq_queue(struct crq_queue *queue,
 	int retrc;
 	struct vio_dev *vdev = to_vio_dev(hostdata->dev);
 
-	queue->msgs = (struct viosrp_crq *)get_zeroed_page(GFP_KERNEL);
-
-	if (!queue->msgs)
-		goto malloc_failed;
 	queue->size = PAGE_SIZE / sizeof(*queue->msgs);
-
-	queue->msg_token = dma_map_single(hostdata->dev, queue->msgs,
-					  queue->size * sizeof(*queue->msgs),
-					  DMA_BIDIRECTIONAL);
-
-	if (dma_mapping_error(hostdata->dev, queue->msg_token))
-		goto map_failed;
+	queue->msgs = dma_alloc_noncoherent(hostdata->dev,
+					    PAGE_SIZE, &queue->msg_token,
+					    DMA_BIDIRECTIONAL, GFP_KERNEL);
+	if (!queue->msg)
+		goto malloc_failed;
 
 	gather_partition_info();
 	set_adapter_info(hostdata);
@@ -395,11 +387,8 @@ static int ibmvscsi_init_crq_queue(struct crq_queue *queue,
 		rc = plpar_hcall_norets(H_FREE_CRQ, vdev->unit_address);
 	} while ((rc == H_BUSY) || (H_IS_LONG_BUSY(rc)));
       reg_crq_failed:
-	dma_unmap_single(hostdata->dev,
-			 queue->msg_token,
-			 queue->size * sizeof(*queue->msgs), DMA_BIDIRECTIONAL);
-      map_failed:
-	free_page((unsigned long)queue->msgs);
+	dma_free_noncoherent(hostdata->dev, PAGE_SIZE, queue->msg,
+			     queue->msg_token, DMA_BIDIRECTIONAL);
       malloc_failed:
 	return -1;
 }
-- 
2.25.1