PCI/MSI: Remove pci_enable_msi_block_auto()

The new pci_msi_vec_count() interface makes pci_enable_msi_block_auto()
superfluous.

Drivers can use pci_msi_vec_count() to learn the maximum number of MSIs
supported by the device, and then call pci_enable_msi_block().

pci_enable_msi_block_auto() was introduced recently, and its only user is
the AHCI driver, which is also updated by this change.

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>

diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index a8b4178..aa4ad98 100644 (file)
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -127,49 +127,22 @@ on the number of vectors that can be allocated; pci_enable_msi_block()
 returns as soon as it finds any constraint that doesn't allow the
 call to succeed.
 
-4.2.3 pci_enable_msi_block_auto
-
-int pci_enable_msi_block_auto(struct pci_dev *dev, int *count)
-
-This variation on pci_enable_msi() call allows a device driver to request
-the maximum possible number of MSIs.  The MSI specification only allows
-interrupts to be allocated in powers of two, up to a maximum of 2^5 (32).
-
-If this function returns a positive number, it indicates that it has
-succeeded and the returned value is the number of allocated interrupts. In
-this case, the function enables MSI on this device and updates dev->irq to
-be the lowest of the new interrupts assigned to it.  The other interrupts
-assigned to the device are in the range dev->irq to dev->irq + returned
-value - 1.
-
-If this function returns a negative number, it indicates an error and
-the driver should not attempt to request any more MSI interrupts for
-this device.
-
-If the device driver needs to know the number of interrupts the device
-supports it can pass the pointer count where that number is stored. The
-device driver must decide what action to take if pci_enable_msi_block_auto()
-succeeds, but returns a value less than the number of interrupts supported.
-If the device driver does not need to know the number of interrupts
-supported, it can set the pointer count to NULL.
-
-4.2.4 pci_disable_msi
+4.2.3 pci_disable_msi
 
 void pci_disable_msi(struct pci_dev *dev)
 
 This function should be used to undo the effect of pci_enable_msi() or
-pci_enable_msi_block() or pci_enable_msi_block_auto().  Calling it restores
-dev->irq to the pin-based interrupt number and frees the previously
-allocated message signaled interrupt(s).  The interrupt may subsequently be
-assigned to another device, so drivers should not cache the value of
-dev->irq.
+pci_enable_msi_block().  Calling it restores dev->irq to the pin-based
+interrupt number and frees the previously allocated message signaled
+interrupt(s).  The interrupt may subsequently be assigned to another
+device, so drivers should not cache the value of dev->irq.
 
 Before calling this function, a device driver must always call free_irq()
 on any interrupt for which it previously called request_irq().
 Failure to do so results in a BUG_ON(), leaving the device with
 MSI enabled and thus leaking its vector.
 
-4.2.5 pci_msi_vec_count
+4.2.4 pci_msi_vec_count
 
 int pci_msi_vec_count(struct pci_dev *dev)
 

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index e2903d0..8516f4d 100644 (file)
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1095,26 +1095,40 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
 {}
 #endif
 
-int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv)
+int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
+                        struct ahci_host_priv *hpriv)
 {
-       int rc;
-       unsigned int maxvec;
+       int rc, nvec;
 
-       if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) {
-               rc = pci_enable_msi_block_auto(pdev, &maxvec);
-               if (rc > 0) {
-                       if ((rc == maxvec) || (rc == 1))
-                               return rc;
-                       /*
-                        * Assume that advantage of multipe MSIs is negated,
-                        * so fallback to single MSI mode to save resources
-                        */
-                       pci_disable_msi(pdev);
-                       if (!pci_enable_msi(pdev))
-                               return 1;
-               }
-       }
+       if (hpriv->flags & AHCI_HFLAG_NO_MSI)
+               goto intx;
+
+       rc = pci_msi_vec_count(pdev);
+       if (rc < 0)
+               goto intx;
+
+       /*
+        * If number of MSIs is less than number of ports then Sharing Last
+        * Message mode could be enforced. In this case assume that advantage
+        * of multipe MSIs is negated and use single MSI mode instead.
+        */
+       if (rc < n_ports)
+               goto single_msi;
+
+       nvec = rc;
+       rc = pci_enable_msi_block(pdev, nvec);
+       if (rc)
+               goto intx;
 
+       return nvec;
+
+single_msi:
+       rc = pci_enable_msi(pdev);
+       if (rc)
+               goto intx;
+       return 1;
+
+intx:
        pci_intx(pdev, 1);
        return 0;
 }
@@ -1281,10 +1295,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
        hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];
 
-       n_msis = ahci_init_interrupts(pdev, hpriv);
-       if (n_msis > 1)
-               hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
-
        /* save initial config */
        ahci_pci_save_initial_config(pdev, hpriv);
 
@@ -1339,6 +1349,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
         */
        n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
 
+       n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
+       if (n_msis > 1)
+               hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
        host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
        if (!host)
                return -ENOMEM;

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index ba6d0a9..76507ab 100644 (file)
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -911,31 +911,6 @@ int pci_enable_msi_block(struct pci_dev *dev, int nvec)
 }
 EXPORT_SYMBOL(pci_enable_msi_block);
 
-int pci_enable_msi_block_auto(struct pci_dev *dev, int *maxvec)
-{
-       int ret, nvec;
-
-       if (dev->current_state != PCI_D0)
-               return -EINVAL;
-
-       ret = pci_msi_vec_count(dev);
-       if (ret < 0)
-               return ret;
-
-       if (maxvec)
-               *maxvec = ret;
-
-       do {
-               nvec = ret;
-               ret = pci_enable_msi_block(dev, nvec);
-       } while (ret > 0);
-
-       if (ret < 0)
-               return ret;
-       return nvec;
-}
-EXPORT_SYMBOL(pci_enable_msi_block_auto);
-
 void pci_msi_shutdown(struct pci_dev *dev)
 {
        struct msi_desc *desc;

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 6691de0..86dcf00 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1164,12 +1164,6 @@ static inline int pci_enable_msi_block(struct pci_dev *dev, int nvec)
        return -ENOSYS;
 }
 
-static inline int
-pci_enable_msi_block_auto(struct pci_dev *dev, int *maxvec)
-{
-       return -ENOSYS;
-}
-
 static inline void pci_msi_shutdown(struct pci_dev *dev)
 { }
 static inline void pci_disable_msi(struct pci_dev *dev)
@@ -1202,7 +1196,6 @@ static inline int pci_msi_enabled(void)
 #else
 int pci_msi_vec_count(struct pci_dev *dev);
 int pci_enable_msi_block(struct pci_dev *dev, int nvec);
-int pci_enable_msi_block_auto(struct pci_dev *dev, int *maxvec);
 void pci_msi_shutdown(struct pci_dev *dev);
 void pci_disable_msi(struct pci_dev *dev);
 int pci_msix_table_size(struct pci_dev *dev);