On 1/15/25 3:30 AM, Damien Le Moal wrote:
> On 1/15/25 03:29, Tomas Henzl wrote:
>> by removing few lines. No functional change.
>>
>> The main part of this change is done by adding a PCI_IRQ_INTX flag into
>> an already existing pci_alloc_irq_vectors invocation.
>> In the current implementation of the pci_alloc_irq_vectors is the sequence of calls
>> msi-x -> msi -> legacy irq and whatever there succeeds stops the
>> call chain. That makes it impossible to merge all instances into as a single call
>> to pci_alloc_irq_vectors since the order of calls there is:
>> multiple msi-x
>> a single msi
>> a single msi-x
>> a legacy irq.
>> but the two last steps can be merged into one which are the msi-x and legacy
>> irq option. With this change we remove a pci(m)_intx call.
>> When PCI_IRQ_INTX flag is set the pci_alloc_irq_vectors succeeds in almost
>> all cases - that makes it possible to convert ahci_init_irq(msi) into a void function.
>> The exception is when dev->irq is zero then the pci_alloc_irq_vectors
>> may return with an error code also pci_intx isn't called from pci_alloc_irq_vectors
>> and thus certain pci calls aren't performed.
>> That's just a negligible issue as later in ahci_init_one the (zero)
>> value of dev->irq is via pci_irq_vector assigned to hpriv->irq.
>> That value is then later tested in ahci_host_activate->ata_host_activate where
>> it is welcomed with a WARN_ON message and fails with setting up irq and
>> then the probe function (ahci_init_one) fails. The special zero value's
>> meaning is that polling mode is being be set up which isn't the case.
>>
>
> Extra blank line not need here.
>
> Beside that, looks OK now. But as Niklas pointed out, this conflicts with a
> patch in the PCI tree. And given that it is too late to queue that for 6.14, can
> you resend a rebased version once 6.14-rc1 is out in a couple of weeks ?
I can do that, thanks.
>
> Thanks !
>
>>
>> Signed-off-by: Tomas Henzl <thenzl@xxxxxxxxxx>
>> ---
>> V2: ahci_init_irq is now a void function
>> V3: a) added an explanation of why we may convert ahci_init_irq into
>> a void function
>> b) fixed the subject line
>> c) added an explanation of why calling pci_alloc_irq_vectors instead
>> of pci_intx is safe
>> d) rebased to latest code state (pci_intx->pcim_intx)
>>
>> drivers/ata/ahci.c | 23 ++++++++++++-----------
>> 1 file changed, 12 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
>> index 8d27c567be1c..3ea2f3adf354 100644
>> --- a/drivers/ata/ahci.c
>> +++ b/drivers/ata/ahci.c
>> @@ -1665,13 +1665,15 @@ static int ahci_get_irq_vector(struct ata_host *host, int port)
>> return pci_irq_vector(to_pci_dev(host->dev), port);
>> }
>>
>> -static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
>> +static void ahci_init_irq(struct pci_dev *pdev, unsigned int n_ports,
>> struct ahci_host_priv *hpriv)
>> {
>> int nvec;
>>
>> - if (hpriv->flags & AHCI_HFLAG_NO_MSI)
>> - return -ENODEV;
>> + if (hpriv->flags & AHCI_HFLAG_NO_MSI) {
>> + pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_INTX);
>> + return;
>> + }
>>
>> /*
>> * If number of MSIs is less than number of ports then Sharing Last
>> @@ -1685,7 +1687,7 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
>> if (!(readl(hpriv->mmio + HOST_CTL) & HOST_MRSM)) {
>> hpriv->get_irq_vector = ahci_get_irq_vector;
>> hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
>> - return nvec;
>> + return;
>> }
>>
>> /*
>> @@ -1700,12 +1702,13 @@ static int ahci_init_msi(struct pci_dev *pdev, unsigned int n_ports,
>>
>> /*
>> * If the host is not capable of supporting per-port vectors, fall
>> - * back to single MSI before finally attempting single MSI-X.
>> + * back to single MSI before finally attempting single MSI-X or
>> + * a legacy INTx.
>> */
>> nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
>> if (nvec == 1)
>> - return nvec;
>> - return pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
>> + return;
>> + pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX | PCI_IRQ_INTX);
>> }
>>
>> static void ahci_mark_external_port(struct ata_port *ap)
>> @@ -1985,10 +1988,8 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
>> }
>> host->private_data = hpriv;
>>
>> - if (ahci_init_msi(pdev, n_ports, hpriv) < 0) {
>> - /* legacy intx interrupts */
>> - pcim_intx(pdev, 1);
>> - }
>> + ahci_init_irq(pdev, n_ports, hpriv);
>> +
>> hpriv->irq = pci_irq_vector(pdev, 0);
>>
>> if (!(hpriv->cap & HOST_CAP_SSS) || ahci_ignore_sss)
>
>
