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    Subject[tip: irq/msi] PCI/MSI: Set pci_dev::msi[x]_enabled early
    The following commit has been merged into the irq/msi branch of tip:

    Commit-ID: c7ecb95ca6a80b29af0f41cc28c58e542637fbc6
    Gitweb: https://git.kernel.org/tip/c7ecb95ca6a80b29af0f41cc28c58e542637fbc6
    Author: Thomas Gleixner <tglx@linutronix.de>
    AuthorDate: Fri, 10 Dec 2021 23:18:44 +01:00
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitterDate: Thu, 16 Dec 2021 22:16:37 +01:00

    PCI/MSI: Set pci_dev::msi[x]_enabled early

    There are quite some places which retrieve the first MSI descriptor to
    evaluate whether the setup is for MSI or MSI-X. That's required because
    pci_dev::msi[x]_enabled is only set when the setup completed successfully.

    There is no real reason why msi[x]_enabled can't be set at the beginning of
    the setup sequence and cleared in case of a failure.

    Implement that so the MSI descriptor evaluations can be converted to simple
    property queries.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Tested-by: Michael Kelley <mikelley@microsoft.com>
    Tested-by: Nishanth Menon <nm@ti.com>
    Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
    Link: https://lore.kernel.org/r/20211210221813.250049810@linutronix.de

    ---
    drivers/pci/msi/msi.c | 23 +++++++++++++++++------
    1 file changed, 17 insertions(+), 6 deletions(-)

    diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
    index eb917fe..5af8d9b 100644
    --- a/drivers/pci/msi/msi.c
    +++ b/drivers/pci/msi/msi.c
    @@ -421,11 +421,18 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
    struct msi_desc *entry;
    int ret;

    - pci_msi_set_enable(dev, 0); /* Disable MSI during set up */
    + /*
    + * Disable MSI during setup in the hardware, but mark it enabled
    + * so that setup code can evaluate it.
    + */
    + pci_msi_set_enable(dev, 0);
    + dev->msi_enabled = 1;

    entry = msi_setup_entry(dev, nvec, affd);
    - if (!entry)
    - return -ENOMEM;
    + if (!entry) {
    + ret = -ENOMEM;
    + goto fail;
    + }

    /* All MSIs are unmasked by default; mask them all */
    pci_msi_mask(entry, msi_multi_mask(entry));
    @@ -452,7 +459,6 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
    /* Set MSI enabled bits */
    pci_intx_for_msi(dev, 0);
    pci_msi_set_enable(dev, 1);
    - dev->msi_enabled = 1;

    pcibios_free_irq(dev);
    dev->irq = entry->irq;
    @@ -461,6 +467,8 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
    err:
    pci_msi_unmask(entry, msi_multi_mask(entry));
    free_msi_irqs(dev);
    +fail:
    + dev->msi_enabled = 0;
    return ret;
    }

    @@ -589,6 +597,9 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,
    pci_msix_clear_and_set_ctrl(dev, 0, PCI_MSIX_FLAGS_MASKALL |
    PCI_MSIX_FLAGS_ENABLE);

    + /* Mark it enabled so setup functions can query it */
    + dev->msix_enabled = 1;
    +
    pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control);
    /* Request & Map MSI-X table region */
    tsize = msix_table_size(control);
    @@ -623,9 +634,8 @@ static int msix_capability_init(struct pci_dev *dev, struct msix_entry *entries,

    dev->msi_irq_groups = groups;

    - /* Set MSI-X enabled bits and unmask the function */
    + /* Disable INTX */
    pci_intx_for_msi(dev, 0);
    - dev->msix_enabled = 1;

    /*
    * Ensure that all table entries are masked to prevent
    @@ -645,6 +655,7 @@ out_free:
    free_msi_irqs(dev);

    out_disable:
    + dev->msix_enabled = 0;
    pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL | PCI_MSIX_FLAGS_ENABLE, 0);

    return ret;
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