ahci: use pci_alloc_irq_vectors

Use the new pci_alloc_irq_vectors API to allocate MSI-X and MSI vectors.
The big advantage over the old code is that we can use the same API for
MSI and MSI-X, and that we don't need to store the MSI-X vector mapping
in driver-private data structures.

This first conversion keeps the probe order as-is: MSI-X multi vector,
MSI multi vector, MSI single vector, MSI-X single vector and last a
single least legacy interrupt line.  There is one small change of
behavior: we now check the "MSI Revert to Single Message" flag for
MSI-X in addition to MSI.

Because the API to find the Linux IRQ number for a MSI/MSI-X vector
is PCI specific, but libahaci is bus-agnostic I had to a
get_irq_vector function pointer to struct ahci_host_priv.  The
alternative would be to move the multi-vector case of ahci_host_activate
to ahci.c and just call ata_host_activate directly from the others
users of ahci_host_activate.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 90eabaf..ba5f11c 100644 (file)
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1400,142 +1400,56 @@ static irqreturn_t ahci_thunderx_irq_handler(int irq, void *dev_instance)
 }
 #endif
 
-/*
- * ahci_init_msix() - optionally enable per-port MSI-X otherwise defer
- * to single msi.
- */
-static int ahci_init_msix(struct pci_dev *pdev, unsigned int n_ports,
-                         struct ahci_host_priv *hpriv, unsigned long flags)
+static int ahci_get_irq_vector(struct ata_host *host, int port)
 {
-       int nvec, i, rc;
-
-       /* Do not init MSI-X if MSI is disabled for the device */
-       if (hpriv->flags & AHCI_HFLAG_NO_MSI)
-               return -ENODEV;
-
-       nvec = pci_msix_vec_count(pdev);
-       if (nvec < 0)
-               return nvec;
-
-       /*
-        * Proper MSI-X implementations will have a vector per-port.
-        * Barring that, we prefer single-MSI over single-MSIX.  If this
-        * check fails (not enough MSI-X vectors for all ports) we will
-        * be called again with the flag clear iff ahci_init_msi()
-        * fails.
-        */
-       if (flags & AHCI_HFLAG_MULTI_MSIX) {
-               if (nvec < n_ports)
-                       return -ENODEV;
-               nvec = n_ports;
-       } else if (nvec) {
-               nvec = 1;
-       } else {
-               /*
-                * Emit dev_err() since this was the non-legacy irq
-                * method of last resort.
-                */
-               rc = -ENODEV;
-               goto fail;
-       }
-
-       for (i = 0; i < nvec; i++)
-               hpriv->msix[i].entry = i;
-       rc = pci_enable_msix_exact(pdev, hpriv->msix, nvec);
-       if (rc < 0)
-               goto fail;
-
-       if (nvec > 1)
-               hpriv->flags |= AHCI_HFLAG_MULTI_MSIX;
-       hpriv->irq = hpriv->msix[0].vector; /* for single msi-x */
-
-       return nvec;
-fail:
-       dev_err(&pdev->dev,
-               "failed to enable MSI-X with error %d, # of vectors: %d\n",
-               rc, nvec);
-
-       return rc;
+       return pci_irq_vector(to_pci_dev(host->dev), port);
 }
 
 static int ahci_init_msi(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)
                return -ENODEV;
 
-       nvec = pci_msi_vec_count(pdev);
-       if (nvec < 0)
-               return nvec;
-
        /*
         * 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 (nvec < n_ports)
-               goto single_msi;
-
-       rc = pci_enable_msi_exact(pdev, nvec);
-       if (rc == -ENOSPC)
-               goto single_msi;
-       if (rc < 0)
-               return rc;
+       nvec = pci_alloc_irq_vectors(pdev, n_ports, INT_MAX,
+                       PCI_IRQ_MSIX | PCI_IRQ_MSI);
+       if (nvec > 0) {
+               if (!(readl(hpriv->mmio + HOST_CTL) & HOST_MRSM)) {
+                       hpriv->get_irq_vector = ahci_get_irq_vector;
+                       hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+                       return nvec;
+               }
 
-       /* fallback to single MSI mode if the controller enforced MRSM mode */
-       if (readl(hpriv->mmio + HOST_CTL) & HOST_MRSM) {
-               pci_disable_msi(pdev);
+               /*
+                * Fallback to single MSI mode if the controller enforced MRSM
+                * mode.
+                */
                printk(KERN_INFO "ahci: MRSM is on, fallback to single MSI\n");
-               goto single_msi;
+               pci_free_irq_vectors(pdev);
        }
 
-       if (nvec > 1)
-               hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
-
-       goto out;
-
-single_msi:
-       nvec = 1;
-
-       rc = pci_enable_msi(pdev);
-       if (rc < 0)
-               return rc;
-out:
-       hpriv->irq = pdev->irq;
-
-       return nvec;
-}
-
-static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
-                               struct ahci_host_priv *hpriv)
-{
-       int nvec;
-
        /*
-        * Try to enable per-port MSI-X.  If the host is not capable
-        * fall back to single MSI before finally attempting single
-        * MSI-X.
+        * -ENOSPC indicated we don't have enough vectors.  Don't bother trying
+        * a single vectors for any other error:
         */
-       nvec = ahci_init_msix(pdev, n_ports, hpriv, AHCI_HFLAG_MULTI_MSIX);
-       if (nvec >= 0)
+       if (nvec < 0 && nvec != -ENOSPC)
                return nvec;
 
-       nvec = ahci_init_msi(pdev, n_ports, hpriv);
-       if (nvec >= 0)
-               return nvec;
-
-       /* try single-msix */
-       nvec = ahci_init_msix(pdev, n_ports, hpriv, 0);
-       if (nvec >= 0)
+       /*
+        * If the host is not capable of supporting per-port vectors, fall
+        * back to single MSI before finally attempting single MSI-X.
+        */
+       nvec = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
+       if (nvec == 1)
                return nvec;
-
-       /* legacy intx interrupts */
-       pci_intx(pdev, 1);
-       hpriv->irq = pdev->irq;
-
-       return 0;
+       return pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
 }
 
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
@@ -1698,11 +1612,12 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
        if (!host)
                return -ENOMEM;
        host->private_data = hpriv;
-       hpriv->msix = devm_kzalloc(&pdev->dev,
-                       sizeof(struct msix_entry) * n_ports, GFP_KERNEL);
-       if (!hpriv->msix)
-               return -ENOMEM;
-       ahci_init_interrupts(pdev, n_ports, hpriv);
+
+       if (ahci_init_msi(pdev, n_ports, hpriv) < 0) {
+               /* legacy intx interrupts */
+               pci_intx(pdev, 1);
+       }
+       hpriv->irq = pdev->irq;
 
        if (!(hpriv->cap & HOST_CAP_SSS) || ahci_ignore_sss)
                host->flags |= ATA_HOST_PARALLEL_SCAN;

diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index 70b06bc..0cc08f8 100644 (file)
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -242,12 +242,10 @@ enum {
        AHCI_HFLAG_NO_FBS               = (1 << 18), /* no FBS */
 
 #ifdef CONFIG_PCI_MSI
-       AHCI_HFLAG_MULTI_MSI            = (1 << 20), /* multiple PCI MSIs */
-       AHCI_HFLAG_MULTI_MSIX           = (1 << 21), /* per-port MSI-X */
+       AHCI_HFLAG_MULTI_MSI            = (1 << 20), /* per-port MSI(-X) */
 #else
        /* compile out MSI infrastructure */
        AHCI_HFLAG_MULTI_MSI            = 0,
-       AHCI_HFLAG_MULTI_MSIX           = 0,
 #endif
        AHCI_HFLAG_WAKE_BEFORE_STOP     = (1 << 22), /* wake before DMA stop */
 
@@ -351,7 +349,6 @@ struct ahci_host_priv {
         * the PHY position in this array.
         */
        struct phy              **phys;
-       struct msix_entry       *msix;          /* Optional MSI-X support */
        unsigned                nports;         /* Number of ports */
        void                    *plat_data;     /* Other platform data */
        unsigned int            irq;            /* interrupt line */
@@ -362,22 +359,11 @@ struct ahci_host_priv {
         */
        void                    (*start_engine)(struct ata_port *ap);
        irqreturn_t             (*irq_handler)(int irq, void *dev_instance);
-};
 
-#ifdef CONFIG_PCI_MSI
-static inline int ahci_irq_vector(struct ahci_host_priv *hpriv, int port)
-{
-       if (hpriv->flags & AHCI_HFLAG_MULTI_MSIX)
-               return hpriv->msix[port].vector;
-       else
-               return hpriv->irq + port;
-}
-#else
-static inline int ahci_irq_vector(struct ahci_host_priv *hpriv, int port)
-{
-       return hpriv->irq;
-}
-#endif
+       /* only required for per-port MSI(-X) support */
+       int                     (*get_irq_vector)(struct ata_host *host,
+                                                 int port);
+};
 
 extern int ahci_ignore_sss;
 

diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 5a1329e..0d028ea 100644 (file)
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -2378,7 +2378,7 @@ static int ahci_port_start(struct ata_port *ap)
        /*
         * Switch to per-port locking in case each port has its own MSI vector.
         */
-       if (hpriv->flags & (AHCI_HFLAG_MULTI_MSI | AHCI_HFLAG_MULTI_MSIX)) {
+       if (hpriv->flags & AHCI_HFLAG_MULTI_MSI) {
                spin_lock_init(&pp->lock);
                ap->lock = &pp->lock;
        }
@@ -2520,7 +2520,7 @@ static int ahci_host_activate_multi_irqs(struct ata_host *host,
         */
        for (i = 0; i < host->n_ports; i++) {
                struct ahci_port_priv *pp = host->ports[i]->private_data;
-               int irq = ahci_irq_vector(hpriv, i);
+               int irq = hpriv->get_irq_vector(host, i);
 
                /* Do not receive interrupts sent by dummy ports */
                if (!pp) {
@@ -2556,10 +2556,15 @@ int ahci_host_activate(struct ata_host *host, struct scsi_host_template *sht)
        int irq = hpriv->irq;
        int rc;
 
-       if (hpriv->flags & (AHCI_HFLAG_MULTI_MSI | AHCI_HFLAG_MULTI_MSIX)) {
+       if (hpriv->flags & AHCI_HFLAG_MULTI_MSI) {
                if (hpriv->irq_handler)
                        dev_warn(host->dev,
                                 "both AHCI_HFLAG_MULTI_MSI flag set and custom irq handler implemented\n");
+               if (!hpriv->get_irq_vector) {
+                       dev_err(host->dev,
+                               "AHCI_HFLAG_MULTI_MSI requires ->get_irq_vector!\n");
+                       return -EIO;
+               }
 
                rc = ahci_host_activate_multi_irqs(host, sht);
        } else {