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    Subject[patch V2 07/31] PCI/MSI: Protect MSI operations
    Date
    To prepare for dynamic extension of MSI-X vectors, protect the MSI
    operations for MSI and MSI-X. This requires to move the invocation of
    irq_create_affinity_masks() out of the descriptor lock section to avoid
    reverse lock ordering vs. CPU hotplug lock as some callers of the PCI/MSI
    allocation interfaces already hold it.

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    ---
    drivers/pci/msi/irqdomain.c | 4 -
    drivers/pci/msi/msi.c | 120 ++++++++++++++++++++++++++------------------
    2 files changed, 73 insertions(+), 51 deletions(-)

    --- a/drivers/pci/msi/irqdomain.c
    +++ b/drivers/pci/msi/irqdomain.c
    @@ -14,7 +14,7 @@ int pci_msi_setup_msi_irqs(struct pci_de

    domain = dev_get_msi_domain(&dev->dev);
    if (domain && irq_domain_is_hierarchy(domain))
    - return msi_domain_alloc_irqs(domain, &dev->dev, nvec);
    + return msi_domain_alloc_irqs_descs_locked(domain, &dev->dev, nvec);

    return pci_msi_legacy_setup_msi_irqs(dev, nvec, type);
    }
    @@ -25,7 +25,7 @@ void pci_msi_teardown_msi_irqs(struct pc

    domain = dev_get_msi_domain(&dev->dev);
    if (domain && irq_domain_is_hierarchy(domain))
    - msi_domain_free_irqs(domain, &dev->dev);
    + msi_domain_free_irqs_descs_locked(domain, &dev->dev);
    else
    pci_msi_legacy_teardown_msi_irqs(dev);
    }
    --- a/drivers/pci/msi/msi.c
    +++ b/drivers/pci/msi/msi.c
    @@ -322,11 +322,13 @@ static void __pci_restore_msix_state(str

    write_msg = arch_restore_msi_irqs(dev);

    + msi_lock_descs(&dev->dev);
    for_each_pci_msi_entry(entry, dev) {
    if (write_msg)
    __pci_write_msi_msg(entry, &entry->msg);
    pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
    }
    + msi_unlock_descs(&dev->dev);

    pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
    }
    @@ -339,20 +341,16 @@ void pci_restore_msi_state(struct pci_de
    EXPORT_SYMBOL_GPL(pci_restore_msi_state);

    static struct msi_desc *
    -msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
    +msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks)
    {
    - struct irq_affinity_desc *masks = NULL;
    struct msi_desc *entry;
    unsigned long prop;
    u16 control;

    - if (affd)
    - masks = irq_create_affinity_masks(nvec, affd);
    -
    /* MSI Entry Initialization */
    entry = alloc_msi_entry(&dev->dev, nvec, masks);
    if (!entry)
    - goto out;
    + return NULL;

    pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
    /* Lies, damned lies, and MSIs */
    @@ -379,8 +377,7 @@ msi_setup_entry(struct pci_dev *dev, int
    if (entry->pci.msi_attrib.is_64)
    prop |= MSI_PROP_64BIT;
    msi_device_set_properties(&dev->dev, prop);
    -out:
    - kfree(masks);
    +
    return entry;
    }

    @@ -416,14 +413,21 @@ static int msi_verify_entries(struct pci
    static int msi_capability_init(struct pci_dev *dev, int nvec,
    struct irq_affinity *affd)
    {
    + struct irq_affinity_desc *masks = NULL;
    struct msi_desc *entry;
    int ret;

    pci_msi_set_enable(dev, 0); /* Disable MSI during set up */

    - entry = msi_setup_entry(dev, nvec, affd);
    - if (!entry)
    - return -ENOMEM;
    + if (affd)
    + masks = irq_create_affinity_masks(nvec, affd);
    +
    + msi_lock_descs(&dev->dev);
    + entry = msi_setup_entry(dev, nvec, masks);
    + if (!entry) {
    + ret = -ENOMEM;
    + goto unlock;
    + }

    /* All MSIs are unmasked by default; mask them all */
    pci_msi_mask(entry, msi_multi_mask(entry));
    @@ -446,11 +450,14 @@ static int msi_capability_init(struct pc

    pcibios_free_irq(dev);
    dev->irq = entry->irq;
    - return 0;
    + goto unlock;

    err:
    pci_msi_unmask(entry, msi_multi_mask(entry));
    free_msi_irqs(dev);
    +unlock:
    + msi_unlock_descs(&dev->dev);
    + kfree(masks);
    return ret;
    }

    @@ -477,23 +484,18 @@ static void __iomem *msix_map_region(str

    static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
    struct msix_entry *entries, int nvec,
    - struct irq_affinity *affd)
    + struct irq_affinity_desc *masks)
    {
    - struct irq_affinity_desc *curmsk, *masks = NULL;
    + int i, vec_count = pci_msix_vec_count(dev);
    + struct irq_affinity_desc *curmsk;
    struct msi_desc *entry;
    void __iomem *addr;
    - int ret, i;
    - int vec_count = pci_msix_vec_count(dev);
    -
    - if (affd)
    - masks = irq_create_affinity_masks(nvec, affd);

    for (i = 0, curmsk = masks; i < nvec; i++) {
    entry = alloc_msi_entry(&dev->dev, 1, curmsk);
    if (!entry) {
    /* No enough memory. Don't try again */
    - ret = -ENOMEM;
    - goto out;
    + return -ENOMEM;
    }

    entry->pci.msi_attrib.is_msix = 1;
    @@ -522,10 +524,7 @@ static int msix_setup_entries(struct pci
    curmsk++;
    }
    msi_device_set_properties(&dev->dev, MSI_PROP_PCI_MSIX | MSI_PROP_64BIT);
    - ret = 0;
    -out:
    - kfree(masks);
    - return ret;
    + return 0;
    }

    static void msix_update_entries(struct pci_dev *dev, struct msix_entry *entries)
    @@ -552,6 +551,41 @@ static void msix_mask_all(void __iomem *
    writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL);
    }

    +static int msix_setup_interrupts(struct pci_dev *dev, void __iomem *base,
    + struct msix_entry *entries, int nvec,
    + struct irq_affinity *affd)
    +{
    + struct irq_affinity_desc *masks = NULL;
    + int ret;
    +
    + if (affd)
    + masks = irq_create_affinity_masks(nvec, affd);
    +
    + msi_lock_descs(&dev->dev);
    + ret = msix_setup_entries(dev, base, entries, nvec, masks);
    + if (ret)
    + goto out_free;
    +
    + ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
    + if (ret)
    + goto out_free;
    +
    + /* Check if all MSI entries honor device restrictions */
    + ret = msi_verify_entries(dev);
    + if (ret)
    + goto out_free;
    +
    + msix_update_entries(dev, entries);
    + goto out_unlock;
    +
    +out_free:
    + free_msi_irqs(dev);
    +out_unlock:
    + msi_unlock_descs(&dev->dev);
    + kfree(masks);
    + return ret;
    +}
    +
    /**
    * msix_capability_init - configure device's MSI-X capability
    * @dev: pointer to the pci_dev data structure of MSI-X device function
    @@ -592,20 +626,9 @@ static int msix_capability_init(struct p
    /* Ensure that all table entries are masked. */
    msix_mask_all(base, tsize);

    - ret = msix_setup_entries(dev, base, entries, nvec, affd);
    + ret = msix_setup_interrupts(dev, base, entries, nvec, affd);
    if (ret)
    - goto out_free;
    -
    - ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
    - if (ret)
    - goto out_free;
    -
    - /* Check if all MSI entries honor device restrictions */
    - ret = msi_verify_entries(dev);
    - if (ret)
    - goto out_free;
    -
    - msix_update_entries(dev, entries);
    + goto out_disable;

    /* Set MSI-X enabled bits and unmask the function */
    pci_intx_for_msi(dev, 0);
    @@ -615,12 +638,8 @@ static int msix_capability_init(struct p
    pcibios_free_irq(dev);
    return 0;

    -out_free:
    - free_msi_irqs(dev);
    -
    out_disable:
    pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
    -
    return ret;
    }

    @@ -725,8 +744,10 @@ void pci_disable_msi(struct pci_dev *dev
    if (!pci_msi_enable || !dev || !dev->msi_enabled)
    return;

    + msi_lock_descs(&dev->dev);
    pci_msi_shutdown(dev);
    free_msi_irqs(dev);
    + msi_unlock_descs(&dev->dev);
    }
    EXPORT_SYMBOL(pci_disable_msi);

    @@ -812,8 +833,10 @@ void pci_disable_msix(struct pci_dev *de
    if (!pci_msi_enable || !dev || !dev->msix_enabled)
    return;

    + msi_lock_descs(&dev->dev);
    pci_msix_shutdown(dev);
    free_msi_irqs(dev);
    + msi_unlock_descs(&dev->dev);
    }
    EXPORT_SYMBOL(pci_disable_msix);

    @@ -874,7 +897,6 @@ int pci_enable_msi(struct pci_dev *dev)

    if (!rc)
    rc = __pci_enable_msi_range(dev, 1, 1, NULL);
    -
    return rc < 0 ? rc : 0;
    }
    EXPORT_SYMBOL(pci_enable_msi);
    @@ -961,11 +983,7 @@ int pci_alloc_irq_vectors_affinity(struc
    struct irq_affinity *affd)
    {
    struct irq_affinity msi_default_affd = {0};
    - int ret = msi_setup_device_data(&dev->dev);
    - int nvecs = -ENOSPC;
    -
    - if (ret)
    - return ret;
    + int ret, nvecs;

    if (flags & PCI_IRQ_AFFINITY) {
    if (!affd)
    @@ -975,6 +993,10 @@ int pci_alloc_irq_vectors_affinity(struc
    affd = NULL;
    }

    + ret = msi_setup_device_data(&dev->dev);
    + if (ret)
    + return ret;
    +
    if (flags & PCI_IRQ_MSIX) {
    nvecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
    affd, flags);
    @@ -1003,7 +1025,7 @@ int pci_alloc_irq_vectors_affinity(struc
    }
    }

    - return nvecs;
    + return -ENOSPC;
    }
    EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);

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