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Date: Thu, 18 Aug 2016 10:46:31 +0200
From: Alexander Gordeev <agordeev@...hat.com>
To: Christoph Hellwig <hch@....de>
Cc: linux-pci@...r.kernel.org, helgaas@...nel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] pci: use positive flags in pci_alloc_irq_vectors
On Thu, Aug 11, 2016 at 07:11:04AM -0700, Christoph Hellwig wrote:
> Instead of using PCI_IRQ_NO* to disable behavior in pci_alloc_irq_vectors
> switch to passing the inverted flags to enable each of them individually.
>
> This is based on a number of pending driver conversions that just happend
> to be a whole more obvious to read this way, and given that we have no
> users in the tree yet it can still easily be done.
>
> I've also added a PCI_IRQ_ALL_TYPES catchall to keep the case of accepting
> all interrupt types very simple.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> Documentation/PCI/MSI-HOWTO.txt | 21 +++++++++------------
> drivers/pci/msi.c | 15 +++++++--------
> include/linux/pci.h | 10 ++++++----
> 3 files changed, 22 insertions(+), 24 deletions(-)
>
> diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
> index c55df29..8faf14a 100644
> --- a/Documentation/PCI/MSI-HOWTO.txt
> +++ b/Documentation/PCI/MSI-HOWTO.txt
> @@ -94,14 +94,11 @@ has a requirements for a minimum number of vectors the driver can pass a
> min_vecs argument set to this limit, and the PCI core will return -ENOSPC
> if it can't meet the minimum number of vectors.
>
> -The flags argument should normally be set to 0, but can be used to pass the
> -PCI_IRQ_NOMSI and PCI_IRQ_NOMSIX flag in case a device claims to support
> -MSI or MSI-X, but the support is broken, or to pass PCI_IRQ_NOLEGACY in
> -case the device does not support legacy interrupt lines.
> -
> -By default this function will spread the interrupts around the available
> -CPUs, but this feature can be disabled by passing the PCI_IRQ_NOAFFINITY
> -flag.
> +The flags argument is used to specify which type of interrupt can be used
> +by the device and the driver (PCI_IRQ_LEGACY, PCI_IRQ_MSI, PCI_IRQ_MSIX).
> +A conveniant short-hand (PCI_IRQ_ALL_TYPES) is also avaiable to ask for
> +any possible kind of interrupt. If the PCI_IRQ_NOAFFINITY flag is set,
> +pci_alloc_irq_vectors will spread the interrupts around the available CPUs.
>
> To get the Linux IRQ numbers passed to request_irq() and free_irq() and the
> vectors, use the following function:
> @@ -131,7 +128,7 @@ larger than the number supported by the device it will automatically be
> capped to the supported limit, so there is no need to query the number of
> vectors supported beforehand:
>
> - nvec = pci_alloc_irq_vectors(pdev, 1, nvec, 0);
> + nvec = pci_alloc_irq_vectors(pdev, 1, nvec, PCI_IRQ_ALL_TYPES)
> if (nvec < 0)
> goto out_err;
>
> @@ -140,7 +137,7 @@ interrupts it can request a particular number of interrupts by passing that
> number to pci_alloc_irq_vectors() function as both 'min_vecs' and
> 'max_vecs' parameters:
>
> - ret = pci_alloc_irq_vectors(pdev, nvec, nvec, 0);
> + ret = pci_alloc_irq_vectors(pdev, nvec, nvec, PCI_IRQ_ALL_TYPES);
> if (ret < 0)
> goto out_err;
>
> @@ -148,7 +145,7 @@ The most notorious example of the request type described above is enabling
> the single MSI mode for a device. It could be done by passing two 1s as
> 'min_vecs' and 'max_vecs':
>
> - ret = pci_alloc_irq_vectors(pdev, 1, 1, 0);
> + ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
> if (ret < 0)
> goto out_err;
>
> @@ -156,7 +153,7 @@ Some devices might not support using legacy line interrupts, in which case
> the PCI_IRQ_NOLEGACY flag can be used to fail the request if the platform
> can't provide MSI or MSI-X interrupts:
>
> - nvec = pci_alloc_irq_vectors(pdev, 1, nvec, PCI_IRQ_NOLEGACY);
> + nvec = pci_alloc_irq_vectors(pdev, 1, nvec, PCI_IRQ_MSI | PCI_IRQ_MSIX);
> if (nvec < 0)
> goto out_err;
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index a02981e..9233e7f 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -1069,7 +1069,7 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
> nvec = maxvec;
>
> for (;;) {
> - if (!(flags & PCI_IRQ_NOAFFINITY)) {
> + if (flags & PCI_IRQ_AFFINITY) {
> dev->irq_affinity = irq_create_affinity_mask(&nvec);
> if (nvec < minvec)
> return -ENOSPC;
> @@ -1105,7 +1105,7 @@ static int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
> **/
> int pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec)
> {
> - return __pci_enable_msi_range(dev, minvec, maxvec, PCI_IRQ_NOAFFINITY);
> + return __pci_enable_msi_range(dev, minvec, maxvec, 0);
> }
> EXPORT_SYMBOL(pci_enable_msi_range);
>
> @@ -1120,7 +1120,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
> return -ERANGE;
>
> for (;;) {
> - if (!(flags & PCI_IRQ_NOAFFINITY)) {
> + if (flags & PCI_IRQ_AFFINITY) {
> dev->irq_affinity = irq_create_affinity_mask(&nvec);
> if (nvec < minvec)
> return -ENOSPC;
> @@ -1160,8 +1160,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
> int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
> int minvec, int maxvec)
> {
> - return __pci_enable_msix_range(dev, entries, minvec, maxvec,
> - PCI_IRQ_NOAFFINITY);
> + return __pci_enable_msix_range(dev, entries, minvec, maxvec, 0);
> }
> EXPORT_SYMBOL(pci_enable_msix_range);
>
> @@ -1187,21 +1186,21 @@ int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> {
> int vecs = -ENOSPC;
>
> - if (!(flags & PCI_IRQ_NOMSIX)) {
> + if (flags & PCI_IRQ_MSIX) {
> vecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
> flags);
> if (vecs > 0)
> return vecs;
> }
>
> - if (!(flags & PCI_IRQ_NOMSI)) {
> + if (flags & PCI_IRQ_MSI) {
> vecs = __pci_enable_msi_range(dev, min_vecs, max_vecs, flags);
> if (vecs > 0)
> return vecs;
> }
>
> /* use legacy irq if allowed */
> - if (!(flags & PCI_IRQ_NOLEGACY) && min_vecs == 1)
> + if ((flags & PCI_IRQ_LEGACY) && min_vecs == 1)
> return 1;
> return vecs;
> }
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 2599a98..fbc1fa6 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1251,10 +1251,12 @@ resource_size_t pcibios_iov_resource_alignment(struct pci_dev *dev, int resno);
> int pci_set_vga_state(struct pci_dev *pdev, bool decode,
> unsigned int command_bits, u32 flags);
>
> -#define PCI_IRQ_NOLEGACY (1 << 0) /* don't use legacy interrupts */
> -#define PCI_IRQ_NOMSI (1 << 1) /* don't use MSI interrupts */
> -#define PCI_IRQ_NOMSIX (1 << 2) /* don't use MSI-X interrupts */
> -#define PCI_IRQ_NOAFFINITY (1 << 3) /* don't auto-assign affinity */
> +#define PCI_IRQ_LEGACY (1 << 0) /* allow legacy interrupts */
> +#define PCI_IRQ_MSI (1 << 1) /* allow MSI interrupts */
> +#define PCI_IRQ_MSIX (1 << 2) /* allow MSI-X interrupts */
> +#define PCI_IRQ_AFFINITY (1 << 3) /* auto-assign affinity */
> +#define PCI_IRQ_ALL_TYPES \
> + (PCI_IRQ_LEGACY | PCI_IRQ_MSI | PCI_IRQ_MSIX)
>
> /* kmem_cache style wrapper around pci_alloc_consistent() */
>
Reviewed-by: Alexander Gordeev <agordeev@...hat.com>
> --
> 2.1.4
>
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