From: Alexander Gordeev <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit 2cf532f5e67c0cfe38c8c100e49280cdadacd2be upstream. In multiple MSI mode all AHCI ports (including dummy) get assigned separate MSI vectors and (as result of execution pci_enable_msi_exact() function) separate IRQ numbers, (mapped to the MSI vectors). Therefore, although interrupts from dummy ports are not desired they are still enabled. We do not request IRQs for dummy ports, but that only means we do not assign AHCI-specific ISRs to corresponding IRQ numbers. As result, dummy port interrupts still could come and traverse all the way from the PCI device to the kernel, causing unnecessary overhead. This update disables IRQs for dummy ports and prevents the described issue. Signed-off-by: Alexander Gordeev <[email protected]> Signed-off-by: Tejun Heo <[email protected]> Tested-by: David Milburn <[email protected]> Cc: [email protected] Fixes: 5ca72c4f7c41 ("AHCI: Support multiple MSIs") Signed-off-by: Jiri Slaby <[email protected]> --- drivers/ata/ahci.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c index 11d34d10f233..b4bdb8859485 100644 --- a/drivers/ata/ahci.c +++ b/drivers/ata/ahci.c @@ -1171,12 +1171,16 @@ int ahci_host_activate(struct ata_host *host, int irq, unsigned int n_msis) for (i = 0; i < host->n_ports; i++) { struct ahci_port_priv *pp = host->ports[i]->private_data; - /* pp is NULL for dummy ports */ - if (pp) - rc = devm_request_threaded_irq(host->dev, - irq + i, ahci_hw_interrupt, - ahci_thread_fn, IRQF_SHARED, - pp->irq_desc, host->ports[i]); + /* Do not receive interrupts sent by dummy ports */ + if (!pp) { + disable_irq(irq + i); + continue; + } + + rc = devm_request_threaded_irq(host->dev, irq + i, + ahci_hw_interrupt, + ahci_thread_fn, IRQF_SHARED, + pp->irq_desc, host->ports[i]); if (rc) goto out_free_irqs; } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
