linux-kernel - [PATCH v2 2/3] ntb: epf: Remove redundant pci_clear

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Message-Id: <20230324013224.5963-2-cai.huoqing@linux.dev>
Date:   Fri, 24 Mar 2023 09:32:19 +0800
From:   Cai Huoqing <cai.huoqing@...ux.dev>
To:     cai.huoqing@...ux.dev
Cc:     Sanjay R Mehta <sanju.mehta@....com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        Jon Mason <jdmason@...zu.us>,
        Dave Jiang <dave.jiang@...el.com>,
        Allen Hubbe <allenbh@...il.com>, Frank Li <Frank.Li@....com>,
        ntb@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/3] ntb: epf: Remove redundant pci_clear_master

Remove pci_clear_master to simplify the code,
the bus-mastering is also cleared in do_pci_disable_device,
like this:
./drivers/pci/pci.c:2197
static void do_pci_disable_device(struct pci_dev *dev)
{
	u16 pci_command;

	pci_read_config_word(dev, PCI_COMMAND, &pci_command);
	if (pci_command & PCI_COMMAND_MASTER) {
		pci_command &= ~PCI_COMMAND_MASTER;
		pci_write_config_word(dev, PCI_COMMAND, pci_command);
	}

	pcibios_disable_device(dev);
}.
And dev->is_busmaster is set to 0 in pci_disable_device.

Signed-off-by: Cai Huoqing <cai.huoqing@...ux.dev>
---
v1->v2: Fix the removed label-err_dma_mask

v1 link:
	https://lore.kernel.org/lkml/20230323115336.12986-2-cai.huoqing@linux.dev/

 drivers/ntb/hw/epf/ntb_hw_epf.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index 3ece49cb18ff..b640aa0bf45e 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -591,7 +591,7 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
 		if (ret) {
 			dev_err(dev, "Cannot set DMA mask\n");
-			goto err_dma_mask;
+			goto err_pci_regions;
 		}
 		dev_warn(&pdev->dev, "Cannot DMA highmem\n");
 	}
@@ -599,14 +599,14 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 	ndev->ctrl_reg = pci_iomap(pdev, ndev->ctrl_reg_bar, 0);
 	if (!ndev->ctrl_reg) {
 		ret = -EIO;
-		goto err_dma_mask;
+		goto err_pci_regions;
 	}
 
 	if (ndev->peer_spad_reg_bar) {
 		ndev->peer_spad_reg = pci_iomap(pdev, ndev->peer_spad_reg_bar, 0);
 		if (!ndev->peer_spad_reg) {
 			ret = -EIO;
-			goto err_dma_mask;
+			goto err_pci_regions;
 		}
 	} else {
 		spad_sz = 4 * readl(ndev->ctrl_reg + NTB_EPF_SPAD_COUNT);
@@ -617,14 +617,11 @@ static int ntb_epf_init_pci(struct ntb_epf_dev *ndev,
 	ndev->db_reg = pci_iomap(pdev, ndev->db_reg_bar, 0);
 	if (!ndev->db_reg) {
 		ret = -EIO;
-		goto err_dma_mask;
+		goto err_pci_regions;
 	}
 
 	return 0;
 
-err_dma_mask:
-	pci_clear_master(pdev);
-
 err_pci_regions:
 	pci_disable_device(pdev);
 
@@ -642,7 +639,6 @@ static void ntb_epf_deinit_pci(struct ntb_epf_dev *ndev)
 	pci_iounmap(pdev, ndev->peer_spad_reg);
 	pci_iounmap(pdev, ndev->db_reg);
 
-	pci_clear_master(pdev);
 	pci_release_regions(pdev);
 	pci_disable_device(pdev);
 	pci_set_drvdata(pdev, NULL);
-- 
2.34.1