[PATCH 10/16] ntb: clean up unnecessary MSI/MSI-X capability find

[PATCH 10/16] ntb: clean up unnecessary MSI/MSI-X capability find

[Yijing Wang]

PCI core will initialize device MSI/MSI-X capability in
pci_msi_init_pci_dev(). So device driver should use
pci_dev->msi_cap/msix_cap to determine whether the device
support MSI/MSI-X instead of using
pci_find_capability(pci_dev, PCI_CAP_ID_MSI/MSIX).
Access to PCIe device config space again will consume more time.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Cc: Jon Mason <jon.mason@intel.com>
Cc: linux-kernel@vger.kernel.org
---
 drivers/ntb/ntb_hw.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index 2dacd19..090d1b2 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -758,16 +758,15 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 	struct pci_dev *pdev = ndev->pdev;
 	struct msix_entry *msix;
 	int msix_entries;
-	int rc, i, pos;
+	int rc, i;
 	u16 val;
 
-	pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
-	if (!pos) {
+	if (!pdev->msix_cap) {
 		rc = -EIO;
 		goto err;
 	}
 
-	rc = pci_read_config_word(pdev, pos + PCI_MSIX_FLAGS, &val);
+	rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
 	if (rc)
 		goto err;
 
-- 
1.7.1

Re: [PATCH 10/16] ntb: clean up unnecessary MSI/MSI-X capability find

[Jon Mason]

On Thu, Aug 08, 2013 at 09:09:34PM +0800, Yijing Wang wrote:
> PCI core will initialize device MSI/MSI-X capability in
> pci_msi_init_pci_dev(). So device driver should use
> pci_dev->msi_cap/msix_cap to determine whether the device
> support MSI/MSI-X instead of using
> pci_find_capability(pci_dev, PCI_CAP_ID_MSI/MSIX).
> Access to PCIe device config space again will consume more time.
> 
> Signed-off-by: Yijing Wang <wangyijing@huawei.com>
> Cc: Jon Mason <jon.mason@intel.com>

Acked-by: Jon Mason <jon.mason@intel.com>

> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/ntb/ntb_hw.c |    7 +++----
>  1 files changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> index 2dacd19..090d1b2 100644
> --- a/drivers/ntb/ntb_hw.c
> +++ b/drivers/ntb/ntb_hw.c
> @@ -758,16 +758,15 @@ static int ntb_setup_msix(struct ntb_device *ndev)
>  	struct pci_dev *pdev = ndev->pdev;
>  	struct msix_entry *msix;
>  	int msix_entries;
> -	int rc, i, pos;
> +	int rc, i;
>  	u16 val;
>  
> -	pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
> -	if (!pos) {
> +	if (!pdev->msix_cap) {
>  		rc = -EIO;
>  		goto err;
>  	}
>  
> -	rc = pci_read_config_word(pdev, pos + PCI_MSIX_FLAGS, &val);
> +	rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
>  	if (rc)
>  		goto err;
>  
> -- 
> 1.7.1
> 
>