Re: [PATCH v2 3/4] ntb: Split ntb_setup_msix() into separate BWD/SNB routines

From: Jon Mason
Date: Tue Mar 11 2014 - 13:20:31 EST


On Tue, Mar 11, 2014 at 05:00:22PM +0100, Alexander Gordeev wrote:
> This is an cleanup effort to make ntb_setup_msix() more
> readable - use ntb_setup_bwd_msix() to init MSI-Xs on
> BWD hardware and ntb_setup_snb_msix() - on SNB hardware.
>
> Function ntb_setup_snb_msix() also initializes MSI-Xs the
> way it should has been done - looping pci_enable_msix()
> until success or failure.
>
> Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
> Cc: Jon Mason <jon.mason@xxxxxxxxx>

Looks good. I will include it in my next release of the NTB driver
(e.g. 3.15).

Thanks,
Jon

> Cc: linux-pci@xxxxxxxxxxxxxxx
> ---
> drivers/ntb/ntb_hw.c | 167 ++++++++++++++++++++++++++++++-------------------
> 1 files changed, 102 insertions(+), 65 deletions(-)
>
> diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
> index 53468f4..1f8decd 100644
> --- a/drivers/ntb/ntb_hw.c
> +++ b/drivers/ntb/ntb_hw.c
> @@ -1079,10 +1079,106 @@ static irqreturn_t ntb_interrupt(int irq, void *dev)
> return IRQ_HANDLED;
> }
>
> -static int ntb_setup_msix(struct ntb_device *ndev)
> +static int ntb_setup_snb_msix(struct ntb_device *ndev, int msix_entries)
> {
> struct pci_dev *pdev = ndev->pdev;
> struct msix_entry *msix;
> + int rc, i;
> +
> + if (msix_entries < ndev->limits.msix_cnt)
> + return -ENOSPC;
> +
> + rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> + if (rc < 0)
> + return rc;
> + else if (rc > 0)
> + return -ENOSPC;
> +
> + for (i = 0; i < msix_entries; i++) {
> + msix = &ndev->msix_entries[i];
> + WARN_ON(!msix->vector);
> +
> + if (i == msix_entries - 1) {
> + rc = request_irq(msix->vector,
> + xeon_event_msix_irq, 0,
> + "ntb-event-msix", ndev);
> + if (rc)
> + goto err;
> + } else {
> + rc = request_irq(msix->vector,
> + xeon_callback_msix_irq, 0,
> + "ntb-callback-msix",
> + &ndev->db_cb[i]);
> + if (rc)
> + goto err;
> + }
> + }
> +
> + ndev->num_msix = msix_entries;
> + ndev->max_cbs = msix_entries - 1;
> +
> + return 0;
> +
> +err:
> + while (--i >= 0) {
> + /* Code never reaches here for entry nr 'ndev->num_msix - 1' */
> + msix = &ndev->msix_entries[i];
> + free_irq(msix->vector, &ndev->db_cb[i]);
> + }
> +
> + pci_disable_msix(pdev);
> + ndev->num_msix = 0;
> +
> + return rc;
> +}
> +
> +static int ntb_setup_bwd_msix(struct ntb_device *ndev, int msix_entries)
> +{
> + struct pci_dev *pdev = ndev->pdev;
> + struct msix_entry *msix;
> + int rc, i;
> +
> +retry:
> + rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> + if (rc < 0)
> + return rc;
> + else if (rc > 0) {
> + dev_warn(&pdev->dev,
> + "Only %d MSI-X vectors. "
> + "Limiting the number of queues to that number.\n",
> + rc);
> + msix_entries = rc;
> + goto retry;
> + }
> +
> + for (i = 0; i < msix_entries; i++) {
> + msix = &ndev->msix_entries[i];
> + WARN_ON(!msix->vector);
> +
> + rc = request_irq(msix->vector, bwd_callback_msix_irq, 0,
> + "ntb-callback-msix", &ndev->db_cb[i]);
> + if (rc)
> + goto err;
> + }
> +
> + ndev->num_msix = msix_entries;
> + ndev->max_cbs = msix_entries;
> +
> + return 0;
> +
> +err:
> + while (--i >= 0)
> + free_irq(msix->vector, &ndev->db_cb[i]);
> +
> + pci_disable_msix(pdev);
> + ndev->num_msix = 0;
> +
> + return rc;
> +}
> +
> +static int ntb_setup_msix(struct ntb_device *ndev)
> +{
> + struct pci_dev *pdev = ndev->pdev;
> int msix_entries;
> int rc, i;
>
> @@ -1105,78 +1201,19 @@ static int ntb_setup_msix(struct ntb_device *ndev)
> for (i = 0; i < msix_entries; i++)
> ndev->msix_entries[i].entry = i;
>
> - rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> - if (rc < 0)
> - goto err1;
> - if (rc > 0) {
> - /* On SNB, the link interrupt is always tied to 4th vector. If
> - * we can't get all 4, then we can't use MSI-X.
> - */
> - if (ndev->hw_type != BWD_HW) {
> - rc = -EIO;
> - goto err1;
> - }
> -
> - dev_warn(&pdev->dev,
> - "Only %d MSI-X vectors. Limiting the number of queues to that number.\n",
> - rc);
> - msix_entries = rc;
> -
> - rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
> - if (rc)
> - goto err1;
> - }
> -
> - for (i = 0; i < msix_entries; i++) {
> - msix = &ndev->msix_entries[i];
> - WARN_ON(!msix->vector);
> -
> - /* Use the last MSI-X vector for Link status */
> - if (ndev->hw_type == BWD_HW) {
> - rc = request_irq(msix->vector, bwd_callback_msix_irq, 0,
> - "ntb-callback-msix", &ndev->db_cb[i]);
> - if (rc)
> - goto err2;
> - } else {
> - if (i == msix_entries - 1) {
> - rc = request_irq(msix->vector,
> - xeon_event_msix_irq, 0,
> - "ntb-event-msix", ndev);
> - if (rc)
> - goto err2;
> - } else {
> - rc = request_irq(msix->vector,
> - xeon_callback_msix_irq, 0,
> - "ntb-callback-msix",
> - &ndev->db_cb[i]);
> - if (rc)
> - goto err2;
> - }
> - }
> - }
> -
> - ndev->num_msix = msix_entries;
> if (ndev->hw_type == BWD_HW)
> - ndev->max_cbs = msix_entries;
> + rc = ntb_setup_bwd_msix(ndev, msix_entries);
> else
> - ndev->max_cbs = msix_entries - 1;
> + rc = ntb_setup_snb_msix(ndev, msix_entries);
> + if (rc)
> + goto err1;
>
> return 0;
>
> -err2:
> - while (--i >= 0) {
> - msix = &ndev->msix_entries[i];
> - if (ndev->hw_type != BWD_HW && i == ndev->num_msix - 1)
> - free_irq(msix->vector, ndev);
> - else
> - free_irq(msix->vector, &ndev->db_cb[i]);
> - }
> - pci_disable_msix(pdev);
> err1:
> kfree(ndev->msix_entries);
> - dev_err(&pdev->dev, "Error allocating MSI-X interrupt\n");
> err:
> - ndev->num_msix = 0;
> + dev_err(&pdev->dev, "Error allocating MSI-X interrupt\n");
> return rc;
> }
>
> --
> 1.7.7.6
>
> --
> Regards,
> Alexander Gordeev
> agordeev@xxxxxxxxxx
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