[PATCH 1/2] libata: add a host flag to ignore detected ATA devices

[Andy Whitcroft <apw@canonical.com>]

Where devices are visible via more than one host we sometimes wish to
indicate that cirtain devices should be ignored on a specific host.  Add a
host flag indicating that this host wishes to ignore ATA specific devices.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
---
 drivers/ata/libata-core.c |    6 ++++++
 include/linux/libata.h    |    1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e0bda9f..18e87bf 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -1973,6 +1973,12 @@ retry:
 	if (class == ATA_DEV_ATA) {
 		if (!ata_id_is_ata(id) && !ata_id_is_cfa(id))
 			goto err_out;
+		if (ap->host->flags & ATA_HOST_IGNORE_ATA &&
+							ata_id_is_ata(id)) {
+			ata_dev_dbg(dev,
+				"host indicates ignore ATA devices, ignored\n");
+			return -ENOENT;
+		}
 	} else {
 		if (ata_id_is_ata(id))
 			goto err_out;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 42378d6..198c8f1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -247,6 +247,7 @@ enum {
 	ATA_HOST_SIMPLEX	= (1 << 0),	/* Host is simplex, one DMA channel per host only */
 	ATA_HOST_STARTED	= (1 << 1),	/* Host started */
 	ATA_HOST_PARALLEL_SCAN	= (1 << 2),	/* Ports on this host can be scanned in parallel */
+	ATA_HOST_IGNORE_ATA	= (1 << 3),	/* Ignore ATA devices on this host. */
 
 	/* bits 24:31 of host->flags are reserved for LLD specific flags */
 
-- 
1.7.9.5