Merge branch 'pci/msi' into next
* pci/msi:
vfio: Use pci_enable_msi_range() and pci_enable_msix_range()
ahci: Use pci_enable_msi_range() instead of pci_enable_msi_block()
ahci: Fix broken fallback to single MSI mode
PCI/MSI: Add pci_enable_msi_exact() and pci_enable_msix_exact()
PCI/MSI: Fix cut-and-paste errors in documentation
PCI/MSI: Add pci_enable_msi() documentation back
PCI/MSI: Fix pci_msix_vec_count() htmldocs failure
PCI/MSI: Fix leak of msi_attrs
PCI/MSI: Check kmalloc() return value, fix leak of name
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index a8d0100..10a9369 100644
--- a/Documentation/PCI/MSI-HOWTO.txt
+++ b/Documentation/PCI/MSI-HOWTO.txt
@@ -82,7 +82,19 @@
has to request that the PCI layer set up the MSI capability for this
device.
-4.2.1 pci_enable_msi_range
+4.2.1 pci_enable_msi
+
+int pci_enable_msi(struct pci_dev *dev)
+
+A successful call allocates ONE interrupt to the device, regardless
+of how many MSIs the device supports. The device is switched from
+pin-based interrupt mode to MSI mode. The dev->irq number is changed
+to a new number which represents the message signaled interrupt;
+consequently, this function should be called before the driver calls
+request_irq(), because an MSI is delivered via a vector that is
+different from the vector of a pin-based interrupt.
+
+4.2.2 pci_enable_msi_range
int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
@@ -147,6 +159,11 @@
return pci_enable_msi_range(pdev, nvec, nvec);
}
+Note, unlike pci_enable_msi_exact() function, which could be also used to
+enable a particular number of MSI-X interrupts, pci_enable_msi_range()
+returns either a negative errno or 'nvec' (not negative errno or 0 - as
+pci_enable_msi_exact() does).
+
4.2.1.3 Single MSI mode
The most notorious example of the request type described above is
@@ -158,7 +175,27 @@
return pci_enable_msi_range(pdev, 1, 1);
}
-4.2.2 pci_disable_msi
+Note, unlike pci_enable_msi() function, which could be also used to
+enable the single MSI mode, pci_enable_msi_range() returns either a
+negative errno or 1 (not negative errno or 0 - as pci_enable_msi()
+does).
+
+4.2.3 pci_enable_msi_exact
+
+int pci_enable_msi_exact(struct pci_dev *dev, int nvec)
+
+This variation on pci_enable_msi_range() call allows a device driver to
+request exactly 'nvec' MSIs.
+
+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.
+
+By contrast with pci_enable_msi_range() function, pci_enable_msi_exact()
+returns zero in case of success, which indicates MSI interrupts have been
+successfully allocated.
+
+4.2.4 pci_disable_msi
void pci_disable_msi(struct pci_dev *dev)
@@ -172,7 +209,7 @@
Failure to do so results in a BUG_ON(), leaving the device with
MSI enabled and thus leaking its vector.
-4.2.3 pci_msi_vec_count
+4.2.4 pci_msi_vec_count
int pci_msi_vec_count(struct pci_dev *dev)
@@ -257,8 +294,8 @@
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
{
- return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,
- 1, nvec);
+ return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
+ 1, nvec);
}
Note the value of 'minvec' parameter is 1. As 'minvec' is inclusive,
@@ -269,8 +306,8 @@
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
{
- return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,
- FOO_DRIVER_MINIMUM_NVEC, nvec);
+ return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
+ FOO_DRIVER_MINIMUM_NVEC, nvec);
}
4.3.1.2 Exact number of MSI-X interrupts
@@ -282,10 +319,15 @@
static int foo_driver_enable_msix(struct foo_adapter *adapter, int nvec)
{
- return pci_enable_msi_range(adapter->pdev, adapter->msix_entries,
- nvec, nvec);
+ return pci_enable_msix_range(adapter->pdev, adapter->msix_entries,
+ nvec, nvec);
}
+Note, unlike pci_enable_msix_exact() function, which could be also used to
+enable a particular number of MSI-X interrupts, pci_enable_msix_range()
+returns either a negative errno or 'nvec' (not negative errno or 0 - as
+pci_enable_msix_exact() does).
+
4.3.1.3 Specific requirements to the number of MSI-X interrupts
As noted above, there could be devices that can not operate with just any
@@ -332,7 +374,64 @@
any error code other than -ENOSPC indicates a fatal error and should not
be retried.
-4.3.2 pci_disable_msix
+4.3.2 pci_enable_msix_exact
+
+int pci_enable_msix_exact(struct pci_dev *dev,
+ struct msix_entry *entries, int nvec)
+
+This variation on pci_enable_msix_range() call allows a device driver to
+request exactly 'nvec' MSI-Xs.
+
+If this function returns a negative number, it indicates an error and
+the driver should not attempt to allocate any more MSI-X interrupts for
+this device.
+
+By contrast with pci_enable_msix_range() function, pci_enable_msix_exact()
+returns zero in case of success, which indicates MSI-X interrupts have been
+successfully allocated.
+
+Another version of a routine that enables MSI-X mode for a device with
+specific requirements described in chapter 4.3.1.3 might look like this:
+
+/*
+ * Assume 'minvec' and 'maxvec' are non-zero
+ */
+static int foo_driver_enable_msix(struct foo_adapter *adapter,
+ int minvec, int maxvec)
+{
+ int rc;
+
+ minvec = roundup_pow_of_two(minvec);
+ maxvec = rounddown_pow_of_two(maxvec);
+
+ if (minvec > maxvec)
+ return -ERANGE;
+
+retry:
+ rc = pci_enable_msix_exact(adapter->pdev,
+ adapter->msix_entries, maxvec);
+
+ /*
+ * -ENOSPC is the only error code allowed to be analyzed
+ */
+ if (rc == -ENOSPC) {
+ if (maxvec == 1)
+ return -ENOSPC;
+
+ maxvec /= 2;
+
+ if (minvec > maxvec)
+ return -ENOSPC;
+
+ goto retry;
+ } else if (rc < 0) {
+ return rc;
+ }
+
+ return maxvec;
+}
+
+4.3.3 pci_disable_msix
void pci_disable_msix(struct pci_dev *dev)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index dc2756f..0237109 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1151,13 +1151,13 @@
static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
struct ahci_host_priv *hpriv)
{
- int rc, nvec;
+ int nvec;
if (hpriv->flags & AHCI_HFLAG_NO_MSI)
goto intx;
- rc = pci_msi_vec_count(pdev);
- if (rc < 0)
+ nvec = pci_msi_vec_count(pdev);
+ if (nvec < 0)
goto intx;
/*
@@ -1165,19 +1165,19 @@
* 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)
+ if (nvec < n_ports)
goto single_msi;
- nvec = rc;
- rc = pci_enable_msi_block(pdev, nvec);
- if (rc)
+ nvec = pci_enable_msi_range(pdev, nvec, nvec);
+ if (nvec == -ENOSPC)
+ goto single_msi;
+ else if (nvec < 0)
goto intx;
return nvec;
single_msi:
- rc = pci_enable_msi(pdev);
- if (rc)
+ if (pci_enable_msi(pdev))
goto intx;
return 1;
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 7a0fec6..955ab79 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -545,9 +545,15 @@
return -ENOMEM;
list_for_each_entry(entry, &pdev->msi_list, list) {
char *name = kmalloc(20, GFP_KERNEL);
- msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
- if (!msi_dev_attr)
+ if (!name)
goto error_attrs;
+
+ msi_dev_attr = kzalloc(sizeof(*msi_dev_attr), GFP_KERNEL);
+ if (!msi_dev_attr) {
+ kfree(name);
+ goto error_attrs;
+ }
+
sprintf(name, "%d", entry->irq);
sysfs_attr_init(&msi_dev_attr->attr);
msi_dev_attr->attr.name = name;
@@ -589,6 +595,7 @@
++count;
msi_attr = msi_attrs[count];
}
+ kfree(msi_attrs);
return ret;
}
@@ -959,7 +966,6 @@
/**
* pci_msix_vec_count - return the number of device's MSI-X table entries
* @dev: pointer to the pci_dev data structure of MSI-X device function
-
* This function returns the number of device's MSI-X table entries and
* therefore the number of MSI-X vectors device is capable of sending.
* It returns a negative errno if the device is not capable of sending MSI-X
diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
index 2103576..9dd49c9 100644
--- a/drivers/vfio/pci/vfio_pci_intrs.c
+++ b/drivers/vfio/pci/vfio_pci_intrs.c
@@ -482,15 +482,19 @@
for (i = 0; i < nvec; i++)
vdev->msix[i].entry = i;
- ret = pci_enable_msix(pdev, vdev->msix, nvec);
- if (ret) {
+ ret = pci_enable_msix_range(pdev, vdev->msix, 1, nvec);
+ if (ret < nvec) {
+ if (ret > 0)
+ pci_disable_msix(pdev);
kfree(vdev->msix);
kfree(vdev->ctx);
return ret;
}
} else {
- ret = pci_enable_msi_block(pdev, nvec);
- if (ret) {
+ ret = pci_enable_msi_range(pdev, 1, nvec);
+ if (ret < nvec) {
+ if (ret > 0)
+ pci_disable_msi(pdev);
kfree(vdev->ctx);
return ret;
}
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 60ab8d7..1e26fc6 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1171,8 +1171,23 @@
void pci_restore_msi_state(struct pci_dev *dev);
int pci_msi_enabled(void);
int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec);
+static inline int pci_enable_msi_exact(struct pci_dev *dev, int nvec)
+{
+ int rc = pci_enable_msi_range(dev, nvec, nvec);
+ if (rc < 0)
+ return rc;
+ return 0;
+}
int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
int minvec, int maxvec);
+static inline int pci_enable_msix_exact(struct pci_dev *dev,
+ struct msix_entry *entries, int nvec)
+{
+ int rc = pci_enable_msix_range(dev, entries, nvec, nvec);
+ if (rc < 0)
+ return rc;
+ return 0;
+}
#else
static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
static inline int pci_enable_msi_block(struct pci_dev *dev, int nvec)
@@ -1191,9 +1206,14 @@
static inline int pci_enable_msi_range(struct pci_dev *dev, int minvec,
int maxvec)
{ return -ENOSYS; }
+static inline int pci_enable_msi_exact(struct pci_dev *dev, int nvec)
+{ return -ENOSYS; }
static inline int pci_enable_msix_range(struct pci_dev *dev,
struct msix_entry *entries, int minvec, int maxvec)
{ return -ENOSYS; }
+static inline int pci_enable_msix_exact(struct pci_dev *dev,
+ struct msix_entry *entries, int nvec)
+{ return -ENOSYS; }
#endif
#ifdef CONFIG_PCIEPORTBUS