From: "Eric W. Biederman" The problem. Because the disable routines leave the msi interrupts in all sorts of half enabled states the enable routines become impossible to implement correctly, and almost impossible to understand. Simplifing this allows me to simply kill the buggy reroute_msix_table, and generally makes the code more maintainable. Signed-off-by: Eric W. Biederman Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Benjamin Herrenschmidt Cc: Rajesh Shah Cc: Andi Kleen Cc: "Protasevich, Natalie" Cc: "Luck, Tony" DESC genirq-msi-simplify-msi-enable-and-disable-fix EDESC From: Andrew Morton Rajesh Shah wrote: > A driver that calls pci_enable_msi() while MSI is already enabled > will hit this BUG_ON. This is different from the behavior of > some other pci functions like pci_enable_device(), which > silently return success if the requested operation is a nop. > It's pretty easy to do the same here too (ditto for MSI-X). Cc: "Eric W. Biederman" Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Benjamin Herrenschmidt Cc: Rajesh Shah Cc: Andi Kleen Cc: "Protasevich, Natalie" Cc: "Luck, Tony" Signed-off-by: Andrew Morton --- drivers/pci/msi.c | 122 +++++--------------------------------------- 1 file changed, 16 insertions(+), 106 deletions(-) diff -puN drivers/pci/msi.c~genirq-msi-simplify-msi-enable-and-disable drivers/pci/msi.c --- a/drivers/pci/msi.c~genirq-msi-simplify-msi-enable-and-disable +++ a/drivers/pci/msi.c @@ -926,7 +926,6 @@ int pci_msi_supported(struct pci_dev * d int pci_enable_msi(struct pci_dev* dev) { int pos, temp, status; - u16 control; if (pci_msi_supported(dev) < 0) return -EINVAL; @@ -941,27 +940,8 @@ int pci_enable_msi(struct pci_dev* dev) if (!pos) return -EINVAL; - if (!msi_lookup_vector(dev, PCI_CAP_ID_MSI)) { - /* Lookup Sucess */ - unsigned long flags; + WARN_ON(!msi_lookup_vector(dev, PCI_CAP_ID_MSI)); - pci_read_config_word(dev, msi_control_reg(pos), &control); - if (control & PCI_MSI_FLAGS_ENABLE) - return 0; /* Already in MSI mode */ - spin_lock_irqsave(&msi_lock, flags); - if (!vector_irq[dev->irq]) { - msi_desc[dev->irq]->msi_attrib.state = 0; - vector_irq[dev->irq] = -1; - nr_released_vectors--; - spin_unlock_irqrestore(&msi_lock, flags); - status = msi_register_init(dev, msi_desc[dev->irq]); - if (status == 0) - enable_msi_mode(dev, pos, PCI_CAP_ID_MSI); - return status; - } - spin_unlock_irqrestore(&msi_lock, flags); - dev->irq = temp; - } /* Check whether driver already requested for MSI-X vectors */ pos = pci_find_capability(dev, PCI_CAP_ID_MSIX); if (pos > 0 && !msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) { @@ -1003,6 +983,8 @@ void pci_disable_msi(struct pci_dev* dev if (!(control & PCI_MSI_FLAGS_ENABLE)) return; + disable_msi_mode(dev, pos, PCI_CAP_ID_MSI); + spin_lock_irqsave(&msi_lock, flags); entry = msi_desc[dev->irq]; if (!entry || !entry->dev || entry->msi_attrib.type != PCI_CAP_ID_MSI) { @@ -1016,14 +998,12 @@ void pci_disable_msi(struct pci_dev* dev pci_name(dev), dev->irq); BUG_ON(entry->msi_attrib.state > 0); } else { - vector_irq[dev->irq] = 0; /* free it */ - nr_released_vectors++; default_vector = entry->msi_attrib.default_vector; spin_unlock_irqrestore(&msi_lock, flags); + msi_free_vector(dev, dev->irq, 0); + /* Restore dev->irq to its default pin-assertion vector */ dev->irq = default_vector; - disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI), - PCI_CAP_ID_MSI); } } @@ -1071,57 +1051,6 @@ static int msi_free_vector(struct pci_de return 0; } -static int reroute_msix_table(int head, struct msix_entry *entries, int *nvec) -{ - int vector = head, tail = 0; - int i, j = 0, nr_entries = 0; - void __iomem *base; - unsigned long flags; - - spin_lock_irqsave(&msi_lock, flags); - while (head != tail) { - nr_entries++; - tail = msi_desc[vector]->link.tail; - if (entries[0].entry == msi_desc[vector]->msi_attrib.entry_nr) - j = vector; - vector = tail; - } - if (*nvec > nr_entries) { - spin_unlock_irqrestore(&msi_lock, flags); - *nvec = nr_entries; - return -EINVAL; - } - vector = ((j > 0) ? j : head); - for (i = 0; i < *nvec; i++) { - j = msi_desc[vector]->msi_attrib.entry_nr; - msi_desc[vector]->msi_attrib.state = 0; /* Mark it not active */ - vector_irq[vector] = -1; /* Mark it busy */ - nr_released_vectors--; - entries[i].vector = vector; - if (j != (entries + i)->entry) { - base = msi_desc[vector]->mask_base; - msi_desc[vector]->msi_attrib.entry_nr = - (entries + i)->entry; - writel( readl(base + j * PCI_MSIX_ENTRY_SIZE + - PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET), base + - (entries + i)->entry * PCI_MSIX_ENTRY_SIZE + - PCI_MSIX_ENTRY_LOWER_ADDR_OFFSET); - writel( readl(base + j * PCI_MSIX_ENTRY_SIZE + - PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET), base + - (entries + i)->entry * PCI_MSIX_ENTRY_SIZE + - PCI_MSIX_ENTRY_UPPER_ADDR_OFFSET); - writel( (readl(base + j * PCI_MSIX_ENTRY_SIZE + - PCI_MSIX_ENTRY_DATA_OFFSET) & 0xff00) | vector, - base + (entries+i)->entry*PCI_MSIX_ENTRY_SIZE + - PCI_MSIX_ENTRY_DATA_OFFSET); - } - vector = msi_desc[vector]->link.tail; - } - spin_unlock_irqrestore(&msi_lock, flags); - - return 0; -} - /** * pci_enable_msix - configure device's MSI-X capability structure * @dev: pointer to the pci_dev data structure of MSI-X device function @@ -1156,9 +1085,6 @@ int pci_enable_msix(struct pci_dev* dev, return -EINVAL; pci_read_config_word(dev, msi_control_reg(pos), &control); - if (control & PCI_MSIX_FLAGS_ENABLE) - return -EINVAL; /* Already in MSI-X mode */ - nr_entries = multi_msix_capable(control); if (nvec > nr_entries) return -EINVAL; @@ -1173,19 +1099,8 @@ int pci_enable_msix(struct pci_dev* dev, } } temp = dev->irq; - if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) { - /* Lookup Sucess */ - nr_entries = nvec; - /* Reroute MSI-X table */ - if (reroute_msix_table(dev->irq, entries, &nr_entries)) { - /* #requested > #previous-assigned */ - dev->irq = temp; - return nr_entries; - } - dev->irq = temp; - enable_msi_mode(dev, pos, PCI_CAP_ID_MSIX); - return 0; - } + WARN_ON(!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)); + /* Check whether driver already requested for MSI vector */ if (pci_find_capability(dev, PCI_CAP_ID_MSI) > 0 && !msi_lookup_vector(dev, PCI_CAP_ID_MSI)) { @@ -1244,37 +1159,32 @@ void pci_disable_msix(struct pci_dev* de if (!(control & PCI_MSIX_FLAGS_ENABLE)) return; + disable_msi_mode(dev, pos, PCI_CAP_ID_MSIX); + temp = dev->irq; if (!msi_lookup_vector(dev, PCI_CAP_ID_MSIX)) { int state, vector, head, tail = 0, warning = 0; unsigned long flags; vector = head = dev->irq; - spin_lock_irqsave(&msi_lock, flags); + dev->irq = temp; /* Restore pin IRQ */ while (head != tail) { + spin_lock_irqsave(&msi_lock, flags); state = msi_desc[vector]->msi_attrib.state; + tail = msi_desc[vector]->link.tail; + spin_unlock_irqrestore(&msi_lock, flags); if (state) warning = 1; - else { - vector_irq[vector] = 0; /* free it */ - nr_released_vectors++; - } - tail = msi_desc[vector]->link.tail; + else if (vector != head) /* Release MSI-X vector */ + msi_free_vector(dev, vector, 0); vector = tail; } - spin_unlock_irqrestore(&msi_lock, flags); + msi_free_vector(dev, vector, 0); if (warning) { - dev->irq = temp; printk(KERN_WARNING "PCI: %s: pci_disable_msix() called without " "free_irq() on all MSI-X vectors\n", pci_name(dev)); BUG_ON(warning > 0); - } else { - dev->irq = temp; - disable_msi_mode(dev, - pci_find_capability(dev, PCI_CAP_ID_MSIX), - PCI_CAP_ID_MSIX); - } } } _