Patchwork [4/5] PCI: Use cached MSI cap in pci_enable_msi_block_auto()

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Submitter Gavin Shan
Date April 4, 2013, 11:39 a.m.
Message ID <1365075572-20763-5-git-send-email-shangw@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/233738/
State Changes Requested
Headers show

Comments

Gavin Shan - April 4, 2013, 11:39 a.m.
The patch intends to use cached MSI capability offset instead of
polling that from config space in pci_enable_msi_block_auto().

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/msi.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)
Bjorn Helgaas - April 4, 2013, 5:19 p.m.
On Thu, Apr 4, 2013 at 5:39 AM, Gavin Shan <shangw@linux.vnet.ibm.com> wrote:
> The patch intends to use cached MSI capability offset instead of
> polling that from config space in pci_enable_msi_block_auto().
>
> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
> ---
>  drivers/pci/msi.c |    7 +++----
>  1 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index 182474d..0b6b254 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -848,14 +848,13 @@ EXPORT_SYMBOL(pci_enable_msi_block);
>
>  int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec)
>  {
> -       int ret, pos, nvec;
> +       int ret, nvec;
>         u16 msgctl;
>
> -       pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
> -       if (!pos)
> +       if (!dev->msi_cap)
>                 return -EINVAL;
>
> -       pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
> +       pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);

I don't understand why this is in a separate patch.  Just add and
populate the cache, then replace all the pci_find_capability() calls
with a dev->msi_cap reference at once.

>         ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
>
>         if (maxvec)
> --
> 1.7.5.4
>
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Patch

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 182474d..0b6b254 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -848,14 +848,13 @@  EXPORT_SYMBOL(pci_enable_msi_block);
 
 int pci_enable_msi_block_auto(struct pci_dev *dev, unsigned int *maxvec)
 {
-	int ret, pos, nvec;
+	int ret, nvec;
 	u16 msgctl;
 
-	pos = pci_find_capability(dev, PCI_CAP_ID_MSI);
-	if (!pos)
+	if (!dev->msi_cap)
 		return -EINVAL;
 
-	pci_read_config_word(dev, pos + PCI_MSI_FLAGS, &msgctl);
+	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &msgctl);
 	ret = 1 << ((msgctl & PCI_MSI_FLAGS_QMASK) >> 1);
 
 	if (maxvec)