Split interrupt service routine into hardware context handler and
threaded context handler. That allows to protect ports with individual
locks rather than with a single host-wide lock, which results in better
parallelism.

Signed-off-by: Alexander Gordeev <agord...@redhat.com>
---
 drivers/ata/acard-ahci.c    |    8 ++---
 drivers/ata/ahci.c          |   54 ++++++++++++++++++-------------
 drivers/ata/ahci.h          |   10 +++--
 drivers/ata/ahci_platform.c |    3 +-
 drivers/ata/libahci.c       |   74 +++++++++++++++++++++++++------------------
 5 files changed, 85 insertions(+), 64 deletions(-)

diff --git a/drivers/ata/acard-ahci.c b/drivers/ata/acard-ahci.c
index 4e94ba2..e429225 100644
--- a/drivers/ata/acard-ahci.c
+++ b/drivers/ata/acard-ahci.c
@@ -409,7 +409,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const 
struct pci_device_id
        struct device *dev = &pdev->dev;
        struct ahci_host_priv *hpriv;
        struct ata_host *host;
-       int n_ports, i, rc;
+       int n_ports, n_msis, i, rc;
 
        VPRINTK("ENTER\n");
 
@@ -436,8 +436,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const 
struct pci_device_id
                return -ENOMEM;
        hpriv->flags |= (unsigned long)pi.private_data;
 
-       if (!(hpriv->flags & AHCI_HFLAG_NO_MSI))
-               pci_enable_msi(pdev);
+       n_msis = ahci_init_interrupts(pdev, hpriv);
 
        hpriv->mmio = pcim_iomap_table(pdev)[AHCI_PCI_BAR];
 
@@ -499,8 +498,7 @@ static int acard_ahci_init_one(struct pci_dev *pdev, const 
struct pci_device_id
        acard_ahci_pci_print_info(host);
 
        pci_set_master(pdev);
-       return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
-                                &acard_ahci_sht);
+       return ahci_host_activate(host, pdev->irq, n_msis, &acard_ahci_sht);
 }
 
 module_pci_driver(acard_ahci_pci_driver);
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 251e57d..e4d915f 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1110,14 +1110,14 @@ int ahci_init_interrupts(struct pci_dev *pdev, struct 
ahci_host_priv *hpriv)
        pci_intx(pdev, 1);
        return 0;
 }
+EXPORT_SYMBOL_GPL(ahci_init_interrupts);
 
 /**
  *     ahci_host_activate - start AHCI host, request IRQs and register it
  *     @host: target ATA host
  *     @irq: base IRQ number to request
  *     @n_msis: number of MSIs allocated for this host
- *     @irq_handler: irq_handler used when requesting IRQs
- *     @irq_flags: irq_flags used when requesting IRQs
+ *     @sht: scsi_host_template to use when registering the host
  *
  *     Similar to ata_host_activate, but requests IRQs according to AHCI-1.1
  *     when multiple MSIs were allocated. That is one MSI per port, starting
@@ -1129,43 +1129,59 @@ int ahci_init_interrupts(struct pci_dev *pdev, struct 
ahci_host_priv *hpriv)
  *     RETURNS:
  *     0 on success, -errno otherwise.
  */
-int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis)
+int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis,
+                      struct scsi_host_template *sht)
 {
        int i, rc;
-
-       /* Sharing Last Message among several ports is not supported */
-       if (n_msis < host->n_ports)
-               return -EINVAL;
+       unsigned int n_irqs;
 
        rc = ata_host_start(host);
        if (rc)
                return rc;
 
-       for (i = 0; i < host->n_ports; i++) {
-               rc = devm_request_threaded_irq(host->dev,
-                       irq + i, ahci_hw_interrupt, ahci_thread_fn, IRQF_SHARED,
-                       dev_driver_string(host->dev), host->ports[i]);
+       n_irqs = min(host->n_ports, n_msis);
+       n_irqs = max(n_irqs, 1u);
+
+       if (n_irqs > 1) {
+               /* Sharing Last Message among several ports is not supported */
+               if (n_irqs < host->n_ports)
+                       return -EINVAL;
+
+               for (i = 0; i < n_irqs; i++) {
+                       rc = devm_request_threaded_irq(host->dev, irq + i,
+                               ahci_multi_irqs_intr, ahci_port_thread_fn,
+                               IRQF_SHARED, dev_driver_string(host->dev),
+                               host->ports[i]);
+                       if (rc)
+                               goto out_free_irqs;
+               }
+       } else {
+               rc = devm_request_threaded_irq(host->dev, irq,
+                       ahci_single_irq_intr, ahci_thread_fn, IRQF_SHARED,
+                       dev_driver_string(host->dev), host);
                if (rc)
-                       goto out_free_irqs;
+                       goto out;
        }
 
-       for (i = 0; i < host->n_ports; i++)
+       for (i = 0; i < n_irqs; i++)
                ata_port_desc(host->ports[i], "irq %d", irq + i);
 
-       rc = ata_host_register(host, &ahci_sht);
+       rc = ata_host_register(host, sht);
        if (rc)
                goto out_free_all_irqs;
 
        return 0;
 
 out_free_all_irqs:
-       i = host->n_ports;
+       i = n_irqs;
 out_free_irqs:
        for (i--; i >= 0; i--)
                devm_free_irq(host->dev, irq + i, host->ports[i]);
+out:
 
        return rc;
 }
+EXPORT_SYMBOL_GPL(ahci_host_activate);
 
 static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
@@ -1265,8 +1281,6 @@ 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);
@@ -1364,11 +1378,7 @@ static int ahci_init_one(struct pci_dev *pdev, const 
struct pci_device_id *ent)
 
        pci_set_master(pdev);
 
-       if (hpriv->flags & AHCI_HFLAG_MULTI_MSI)
-               return ahci_host_activate(host, pdev->irq, n_msis);
-
-       return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
-                                &ahci_sht);
+       return ahci_host_activate(host, pdev->irq, n_msis, &ahci_sht);
 }
 
 module_pci_driver(ahci_pci_driver);
diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h
index b830e6c..ed1fbc8 100644
--- a/drivers/ata/ahci.h
+++ b/drivers/ata/ahci.h
@@ -231,7 +231,6 @@ enum {
        AHCI_HFLAG_DELAY_ENGINE         = (1 << 15), /* do not start engine on
                                                        port start (wait until
                                                        error-handling stage) */
-       AHCI_HFLAG_MULTI_MSI            = (1 << 16), /* multiple PCI MSIs */
 
        /* ap->flags bits */
 
@@ -361,11 +360,14 @@ int ahci_port_resume(struct ata_port *ap);
 void ahci_set_em_messages(struct ahci_host_priv *hpriv,
                          struct ata_port_info *pi);
 int ahci_reset_em(struct ata_host *host);
-irqreturn_t ahci_interrupt(int irq, void *dev_instance);
-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance);
+irqreturn_t ahci_single_irq_intr(int irq, void *dev_instance);
+irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance);
 irqreturn_t ahci_thread_fn(int irq, void *dev_instance);
+irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance);
 void ahci_print_info(struct ata_host *host, const char *scc_s);
-int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis);
+int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis,
+                      struct scsi_host_template *sht);
+int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv);
 
 static inline void __iomem *__ahci_port_base(struct ata_host *host,
                                             unsigned int port_no)
diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
index 7a8a284..b10cd87 100644
--- a/drivers/ata/ahci_platform.c
+++ b/drivers/ata/ahci_platform.c
@@ -211,8 +211,7 @@ static int ahci_probe(struct platform_device *pdev)
        ahci_init_controller(host);
        ahci_print_info(host, "platform");
 
-       rc = ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
-                              &ahci_platform_sht);
+       rc = ahci_host_activate(host, irq, 0, &ahci_platform_sht);
        if (rc)
                goto pdata_exit;
 
diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
index 34c8216..68b3bdd 100644
--- a/drivers/ata/libahci.c
+++ b/drivers/ata/libahci.c
@@ -1655,9 +1655,9 @@ static void ahci_error_intr(struct ata_port *ap, u32 
irq_stat)
                ata_port_abort(ap);
 }
 
-static void ahci_handle_port_interrupt(struct ata_port *ap,
-                                      void __iomem *port_mmio, u32 status)
+static void ahci_handle_port_interrupt(struct ata_port *ap, u32 status)
 {
+       void __iomem *port_mmio = ahci_port_base(ap);
        struct ata_eh_info *ehi = &ap->link.eh_info;
        struct ahci_port_priv *pp = ap->private_data;
        struct ahci_host_priv *hpriv = ap->host->private_data;
@@ -1740,22 +1740,10 @@ static void ahci_handle_port_interrupt(struct ata_port 
*ap,
        }
 }
 
-void ahci_port_intr(struct ata_port *ap)
-{
-       void __iomem *port_mmio = ahci_port_base(ap);
-       u32 status;
-
-       status = readl(port_mmio + PORT_IRQ_STAT);
-       writel(status, port_mmio + PORT_IRQ_STAT);
-
-       ahci_handle_port_interrupt(ap, port_mmio, status);
-}
-
-irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+irqreturn_t ahci_port_thread_fn(int irq, void *dev_instance)
 {
        struct ata_port *ap = dev_instance;
        struct ahci_port_priv *pp = ap->private_data;
-       void __iomem *port_mmio = ahci_port_base(ap);
        unsigned long flags;
        u32 status;
 
@@ -1766,14 +1754,43 @@ irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
        spin_unlock_irqrestore(&ap->host->lock, flags);
 
        spin_lock_bh(ap->lock);
-       ahci_handle_port_interrupt(ap, port_mmio, status);
+       ahci_handle_port_interrupt(ap, status);
        spin_unlock_bh(ap->lock);
 
        return IRQ_HANDLED;
 }
+EXPORT_SYMBOL_GPL(ahci_port_thread_fn);
+
+irqreturn_t ahci_thread_fn(int irq, void *dev_instance)
+{
+       struct ata_host *host = dev_instance;
+       struct ahci_host_priv *hpriv = host->private_data;
+       u32 irq_masked = hpriv->port_map;
+       unsigned int i;
+
+       for (i = 0; i < host->n_ports; i++) {
+               struct ata_port *ap;
+
+               if (!(irq_masked & (1 << i)))
+                       continue;
+
+               ap = host->ports[i];
+               if (ap) {
+                       ahci_port_thread_fn(irq, ap);
+                       VPRINTK("port %u\n", i);
+               } else {
+                       VPRINTK("port %u (no irq)\n", i);
+                       if (ata_ratelimit())
+                               dev_warn(host->dev,
+                                        "interrupt on disabled port %u\n", i);
+               }
+       }
+
+       return IRQ_HANDLED;
+}
 EXPORT_SYMBOL_GPL(ahci_thread_fn);
 
-void ahci_hw_port_interrupt(struct ata_port *ap)
+void ahci_update_intr_status(struct ata_port *ap)
 {
        void __iomem *port_mmio = ahci_port_base(ap);
        struct ahci_port_priv *pp = ap->private_data;
@@ -1785,7 +1802,7 @@ void ahci_hw_port_interrupt(struct ata_port *ap)
        pp->intr_status |= status;
 }
 
-irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
+irqreturn_t ahci_multi_irqs_intr(int irq, void *dev_instance)
 {
        struct ata_port *ap_this = dev_instance;
        struct ahci_port_priv *pp = ap_this->private_data;
@@ -1821,7 +1838,7 @@ irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
 
                ap = host->ports[i];
                if (ap) {
-                       ahci_hw_port_interrupt(ap);
+                       ahci_update_intr_status(ap);
                        VPRINTK("port %u\n", i);
                } else {
                        VPRINTK("port %u (no irq)\n", i);
@@ -1839,9 +1856,9 @@ irqreturn_t ahci_hw_interrupt(int irq, void *dev_instance)
 
        return IRQ_WAKE_THREAD;
 }
-EXPORT_SYMBOL_GPL(ahci_hw_interrupt);
+EXPORT_SYMBOL_GPL(ahci_multi_irqs_intr);
 
-irqreturn_t ahci_interrupt(int irq, void *dev_instance)
+irqreturn_t ahci_single_irq_intr(int irq, void *dev_instance)
 {
        struct ata_host *host = dev_instance;
        struct ahci_host_priv *hpriv;
@@ -1871,7 +1888,7 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance)
 
                ap = host->ports[i];
                if (ap) {
-                       ahci_port_intr(ap);
+                       ahci_update_intr_status(ap);
                        VPRINTK("port %u\n", i);
                } else {
                        VPRINTK("port %u (no irq)\n", i);
@@ -1898,9 +1915,9 @@ irqreturn_t ahci_interrupt(int irq, void *dev_instance)
 
        VPRINTK("EXIT\n");
 
-       return IRQ_RETVAL(handled);
+       return handled ? IRQ_WAKE_THREAD : IRQ_NONE;
 }
-EXPORT_SYMBOL_GPL(ahci_interrupt);
+EXPORT_SYMBOL_GPL(ahci_single_irq_intr);
 
 static unsigned int ahci_qc_issue(struct ata_queued_cmd *qc)
 {
@@ -2294,13 +2311,8 @@ static int ahci_port_start(struct ata_port *ap)
         */
        pp->intr_mask = DEF_PORT_IRQ;
 
-       /*
-        * Switch to per-port locking in case each port has its own MSI vector.
-        */
-       if ((hpriv->flags & AHCI_HFLAG_MULTI_MSI)) {
-               spin_lock_init(&pp->lock);
-               ap->lock = &pp->lock;
-       }
+       spin_lock_init(&pp->lock);
+       ap->lock = &pp->lock;
 
        ap->private_data = pp;
 
-- 
1.7.7.6


-- 
Regards,
Alexander Gordeev
agord...@redhat.com
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