[SCSI] libata, libsas: introduce sched_eh and end_eh port ops

When managing shost->host_eh_scheduled libata assumes that there is a
1:1 shost-to-ata_port relationship.  libsas creates a 1:N relationship
so it needs to manage host_eh_scheduled cumulatively at the host level.
The sched_eh and end_eh port port ops allow libsas to track when domain
devices enter/leave the "eh-pending" state under ha->lock (previously
named ha->state_lock, but it is no longer just a lock for ha->state
changes).

Since host_eh_scheduled indicates eh without backing commands pinning
the device it can be deallocated at any time.  Move the taking of the
domain_device reference under the port_lock to guarantee that the
ata_port stays around for the duration of eh.

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

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/libata.h b/include/linux/libata.h
index 6e887c742a2..53da442f892 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -846,6 +846,8 @@ struct ata_port_operations {
         void (*error_handler)(struct ata_port *ap);
         void (*lost_interrupt)(struct ata_port *ap);
         void (*post_internal_cmd)(struct ata_queued_cmd *qc);
+        void (*sched_eh)(struct ata_port *ap);
+        void (*end_eh)(struct ata_port *ap);
 
         /*
          * Optional features
@@ -1167,6 +1169,8 @@ extern void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
                       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
                       ata_postreset_fn_t postreset);
 extern void ata_std_error_handler(struct ata_port *ap);
+extern void ata_std_sched_eh(struct ata_port *ap);
+extern void ata_std_end_eh(struct ata_port *ap);
 extern int ata_link_nr_enabled(struct ata_link *link);
 
 /*