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
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -127,49 +127,22 @@
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
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1095,26 +1095,40 @@
{}
#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 @@
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 @@
*/
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
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -911,31 +911,6 @@
}
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
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1164,12 +1164,6 @@
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 @@
#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);