[SCSI] libata: export ata_port suspend/resume infrastructure for sas

Reuse ata_port_{suspend|resume}_common for sas.  This path is chosen
over adding coordination between ata-tranport and sas-transport because
libsas wants to revalidate the domain at resume-time at the host level.
It can not validate links have resumed properly until libata has had a
chance to perform its revalidation, and any sane placing of an ata_port
in the sas-transport model would delay it's resumption until after the
host.

Export the common portion of port suspend/resume (bypass pm_runtime),
and allow sas to perform these operations asynchronously (similar to the
libsas async-ata probe implmentation).  Async operation is determined by
having an external, rather than stack based, location for storing the
result of the operation.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jacek Danecki <jacek.danecki@intel.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 31a2853e9530..cc834e1136b2 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1013,6 +1013,17 @@ extern bool ata_link_offline(struct ata_link *link);
 #ifdef CONFIG_PM
 extern int ata_host_suspend(struct ata_host *host, pm_message_t mesg);
 extern void ata_host_resume(struct ata_host *host);
+extern int ata_sas_port_async_suspend(struct ata_port *ap, int *async);
+extern int ata_sas_port_async_resume(struct ata_port *ap, int *async);
+#else
+static inline int ata_sas_port_async_suspend(struct ata_port *ap, int *async)
+{
+	return 0;
+}
+static inline int ata_sas_port_async_resume(struct ata_port *ap, int *async)
+{
+	return 0;
+}
 #endif
 extern int ata_ratelimit(void);
 extern void ata_msleep(struct ata_port *ap, unsigned int msecs);