PCI/portdrv: Consolidate comments

Consolidate some repetitive comments so we can see the code better.  No
functional change.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 72fcbe5567dde0905896a8d093121b1112f51fd2..accd16082348df23511a0b9a44c4fae1994501b3 100644 (file)
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -56,40 +56,27 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
 {
        int nr_entries, entry, nvec = 0;
 
-       /*
-        * Allocate as many entries as the port wants, so that we can check
-        * which of them will be useful.  Moreover, if nr_entries is correctly
-        * equal to the number of entries this port actually uses, we'll happily
-        * go through without any tricks.
-        */
+       /* Allocate the maximum possible number of MSI/MSI-X vectors */
        nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
                        PCI_IRQ_MSIX | PCI_IRQ_MSI);
        if (nr_entries < 0)
                return nr_entries;
 
+       /*
+        * The Interrupt Message Number indicates which vector is used, i.e.,
+        * the MSI-X table entry or the MSI offset between the base Message
+        * Data and the generated interrupt message.  See PCIe r3.1, sec
+        * 7.8.2, 7.10.10, 7.31.2.
+        */
        if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) {
                u16 reg16;
 
-               /*
-                * Per PCIe r3.1, sec 6.1.6, "PME and Hot-Plug Event
-                * interrupts (when both are implemented) always share the
-                * same MSI or MSI-X vector, as indicated by the Interrupt
-                * Message Number field in the PCI Express Capabilities
-                * register".
-                *
-                * Per sec 7.8.2, "For MSI, the [Interrupt Message Number]
-                * indicates the offset between the base Message Data and
-                * the interrupt message that is generated."
-                *
-                * "For MSI-X, the [Interrupt Message Number] indicates
-                * which MSI-X Table entry is used to generate the
-                * interrupt message."
-                */
                pcie_capability_read_word(dev, PCI_EXP_FLAGS, &reg16);
                entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
                if (entry >= nr_entries)
                        goto out_free_irqs;
 
+               /* PME and hotplug share an MSI/MSI-X vector */
                irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pci_irq_vector(dev, entry);
                irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pci_irq_vector(dev, entry);
 
@@ -99,19 +86,6 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
        if (mask & PCIE_PORT_SERVICE_AER) {
                u32 reg32, pos;
 
-               /*
-                * Per PCIe r3.1, sec 7.10.10, the Advanced Error Interrupt
-                * Message Number in the Root Error Status register
-                * indicates which MSI/MSI-X vector is used for AER.
-                *
-                * "For MSI, the [Advanced Error Interrupt Message Number]
-                * indicates the offset between the base Message Data and
-                * the interrupt message that is generated."
-                *
-                * "For MSI-X, the [Advanced Error Interrupt Message
-                * Number] indicates which MSI-X Table entry is used to
-                * generate the interrupt message."
-                */
                pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
                pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
                entry = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
@@ -126,19 +100,6 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
        if (mask & PCIE_PORT_SERVICE_DPC) {
                u16 reg16, pos;
 
-               /*
-                * Per PCIe r4.0 (v0.9), sec 7.9.15.2, the DPC Interrupt
-                * Message Number in the DPC Capability register indicates
-                * which MSI/MSI-X vector is used for DPC.
-                *
-                * "For MSI, the [DPC Interrupt Message Number] indicates
-                * the offset between the base Message Data and the
-                * interrupt message that is generated."
-                *
-                * "For MSI-X, the [DPC Interrupt Message Number] indicates
-                * which MSI-X Table entry is used to generate the
-                * interrupt message."
-                */
                pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
                pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP, &reg16);
                entry = reg16 & PCI_EXP_DPC_IRQ;
@@ -150,16 +111,10 @@ static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
                nvec = max(nvec, entry + 1);
        }
 
-       /*
-        * If nvec is equal to the allocated number of entries, we can just use
-        * what we have.  Otherwise, the port has some extra entries not for the
-        * services we know and we need to work around that.
-        */
+       /* If we allocated more than we need, free them and allocate fewer */
        if (nvec != nr_entries) {
-               /* Drop the temporary MSI-X setup */
                pci_free_irq_vectors(dev);
 
-               /* Now allocate the MSI-X vectors for real */
                nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
                                PCI_IRQ_MSIX | PCI_IRQ_MSI);
                if (nr_entries < 0)