libata: add ata_ratelimit(), use it in AHCI driver irq handler

3 files changed, 50 insertions, 6 deletions

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index c2c8fa828e24..5ec866b00479 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -672,17 +672,36 @@ static irqreturn_t ahci_interrupt (int irq, void *dev_instance, struct pt_regs *
 
         for (i = 0; i < host_set->n_ports; i++) {
                 struct ata_port *ap;
-                u32 tmp;
 
-                VPRINTK("port %u\n", i);
+                if (!(irq_stat & (1 << i)))
+                        continue;
+
                 ap = host_set->ports[i];
-                tmp = irq_stat & (1 << i);
-                if (tmp && ap) {
+                if (ap) {
                         struct ata_queued_cmd *qc;
                         qc = ata_qc_from_tag(ap, ap->active_tag);
-                        if (ahci_host_intr(ap, qc))
-                                irq_ack |= (1 << i);
+                        if (!ahci_host_intr(ap, qc))
+                                if (ata_ratelimit()) {
+                                        struct pci_dev *pdev =
+                                          to_pci_dev(ap->host_set->dev);
+                                        printk(KERN_WARNING
+                                          "ahci(%s): unhandled interrupt on port %u\n",
+                                          pci_name(pdev), i);
+                                }
+
+                        VPRINTK("port %u\n", i);
+                } else {
+                        VPRINTK("port %u (no irq)\n", i);
+                        if (ata_ratelimit()) {
+                                struct pci_dev *pdev =
+                                  to_pci_dev(ap->host_set->dev);
+                                printk(KERN_WARNING
+                                  "ahci(%s): interrupt on disabled port %u\n",
+                                  pci_name(pdev), i);
+                        }
                 }
+
+                irq_ack |= (1 << i);
         }
 
         if (irq_ack) {
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index f0894bfa908b..ceffaef37d17 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -48,6 +48,7 @@
 #include <linux/completion.h>
 #include <linux/suspend.h>
 #include <linux/workqueue.h>
+#include <linux/jiffies.h>
 #include <scsi/scsi.h>
 #include "scsi.h"
 #include "scsi_priv.h"
@@ -4688,6 +4689,27 @@ static void __exit ata_exit(void)
 module_init(ata_init);
 module_exit(ata_exit);
 
+static unsigned long ratelimit_time;
+static spinlock_t ata_ratelimit_lock = SPIN_LOCK_UNLOCKED;
+
+int ata_ratelimit(void)
+{
+        int rc;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ata_ratelimit_lock, flags);
+
+        if (time_after(jiffies, ratelimit_time)) {
+                rc = 1;
+                ratelimit_time = jiffies + (HZ/5);
+        } else
+                rc = 0;
+
+        spin_unlock_irqrestore(&ata_ratelimit_lock, flags);
+
+        return rc;
+}
+
 /*
  * libata is essentially a library of internal helper functions for
  * low-level ATA host controller drivers.  As such, the API/ABI is
@@ -4729,6 +4751,7 @@ EXPORT_SYMBOL_GPL(sata_phy_reset);
 EXPORT_SYMBOL_GPL(__sata_phy_reset);
 EXPORT_SYMBOL_GPL(ata_bus_reset);
 EXPORT_SYMBOL_GPL(ata_port_disable);
+EXPORT_SYMBOL_GPL(ata_ratelimit);
 EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
 EXPORT_SYMBOL_GPL(ata_scsi_queuecmd);
 EXPORT_SYMBOL_GPL(ata_scsi_error);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 4d45179872cc..7929cfc9318d 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -410,6 +410,8 @@ extern int ata_scsi_queuecmd(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmn
 extern int ata_scsi_error(struct Scsi_Host *host);
 extern int ata_scsi_release(struct Scsi_Host *host);
 extern unsigned int ata_host_intr(struct ata_port *ap, struct ata_queued_cmd *qc);
+extern int ata_ratelimit(void);
+
 /*
  * Default driver ops implementations
  */