ata: core: fix irq description on AHCI single irq systems

On my machine with single irq AHCI just the PCI id is printed as
description in /proc/interrupts.
I found a related discussion from beginning of this year:
http://www.gossamer-threads.com/lists/linux/kernel/2117335

Seems like 4f37b504768c ("libata: Use dev_name() for request_irq() to
distinguish devices") tried to fix displaying a proper interrupt
description for one scenario but broke it for another one.

The mentioned discussion ended in the current situation being
considered as broken but w/o a patch to fix it.

The following patch is based on a proposal in this mail thread.
Now the interrupt is properly described as:
PCI-MSI 512000-edge      ahci[0000:00:1f.2]

By combining both values also the scenario that commit 4f37b504768c
("libata: Use dev_name() for request_irq() to distinguish devices")
refers to should still be fine. There it should look like this now:
ahci[20100000.ide]

Using managed memory allocation ensures that the irq description
lives at least as long as the interrupt.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index b79cb10e289e8a1eb52c2887b3e7c135952beb0f..60e368610c749d5476d7e05b53d1f9351db8322e 100644 (file)
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -6223,6 +6223,7 @@ int ata_host_activate(struct ata_host *host, int irq,
                      struct scsi_host_template *sht)
 {
        int i, rc;
+       char *irq_desc;
 
        rc = ata_host_start(host);
        if (rc)
@@ -6234,8 +6235,14 @@ int ata_host_activate(struct ata_host *host, int irq,
                return ata_host_register(host, sht);
        }
 
+       irq_desc = devm_kasprintf(host->dev, GFP_KERNEL, "%s[%s]",
+                                 dev_driver_string(host->dev),
+                                 dev_name(host->dev));
+       if (!irq_desc)
+               return -ENOMEM;
+
        rc = devm_request_irq(host->dev, irq, irq_handler, irq_flags,
-                             dev_name(host->dev), host);
+                             irq_desc, host);
        if (rc)
                return rc;