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Message-Id: <d9037b2ab455abff30e9c2da0a98e5e01b0940d7.1387140921.git.agordeev@redhat.com>
Date: Mon, 16 Dec 2013 09:35:00 +0100
From: Alexander Gordeev <agordeev@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Alexander Gordeev <agordeev@...hat.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Michael Ellerman <michael@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Tejun Heo <tj@...nel.org>,
Ben Hutchings <bhutchings@...arflare.com>,
David Laight <David.Laight@...LAB.COM>,
Mark Lord <kernel@...rt.ca>, "H. Peter Anvin" <hpa@...or.com>,
linux-pci@...r.kernel.org
Subject: [PATCH v4 7/9] PCI/MSI: Get rid of pci_enable_msi_block_auto() interface
As result of introduction of pci_get_msi_vec_count()
interface pci_enable_msi_block_auto() function became
superflous.
To enable maximum possible number of MSIs drivers will
first obtain that number from pci_get_msi_vec_count()
function and then call pci_enable_msi_block() interface.
Function pci_enable_msi_block_auto() has been introduced
recently and its only user is AHCI driver, which is also
updated by this change.
Signed-off-by: Alexander Gordeev <agordeev@...hat.com>
Acked-by: Tejun Heo <tj@...nel.org>
---
Documentation/PCI/MSI-HOWTO.txt | 39 ++++-----------------------
drivers/ata/ahci.c | 56 ++++++++++++++++++++++++--------------
drivers/pci/msi.c | 25 -----------------
include/linux/pci.h | 7 -----
4 files changed, 41 insertions(+), 86 deletions(-)
diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
index c03b815..8d35d62 100644
--- 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_get_msi_vec_count
+4.2.4 pci_get_msi_vec_count
int pci_get_msi_vec_count(struct pci_dev *dev)
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index e2903d0..e490d42 100644
--- 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_get_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 8915edb..de1acb9 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -902,31 +902,6 @@ 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_get_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 997751d..8d9eb6b 100644
--- 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_get_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);
--
1.7.7.6
--
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