libata: make ata_print_id atomic

This variable is incremented from multiple contexts (module_init via
libata-lldds and the libsas discovery thread).  Make it atomic to head
off any chance of libsas and libata creating duplicate ids.

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

3 files changed, 5 insertions, 5 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e0bda9ff89cd..28db50b57b91 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -95,7 +95,7 @@ static unsigned int ata_dev_set_xfermode(struct ata_device *dev);
 static void ata_dev_xfermask(struct ata_device *dev);
 static unsigned long ata_dev_blacklisted(const struct ata_device *dev);
 
-unsigned int ata_print_id = 1;
+atomic_t ata_print_id = ATOMIC_INIT(1);
 
 struct ata_force_param {
         const char      *name;
@@ -6029,7 +6029,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
 
         /* give ports names and add SCSI hosts */
         for (i = 0; i < host->n_ports; i++)
-                host->ports[i]->print_id = ata_print_id++;
+                host->ports[i]->print_id = atomic_inc_return(&ata_print_id);
 
 
         /* Create associated sysfs transport objects  */
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 1ee00c8b5b04..93dabdcd2cbe 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3843,7 +3843,7 @@ int ata_sas_async_port_init(struct ata_port *ap)
         int rc = ap->ops->port_start(ap);
 
         if (!rc) {
-                ap->print_id = ata_print_id++;
+                ap->print_id = atomic_inc_return(&ata_print_id);
                 __ata_port_probe(ap);
         }
 
@@ -3867,7 +3867,7 @@ int ata_sas_port_init(struct ata_port *ap)
         int rc = ap->ops->port_start(ap);
 
         if (!rc) {
-                ap->print_id = ata_print_id++;
+                ap->print_id = atomic_inc_return(&ata_print_id);
                 rc = ata_port_probe(ap);
         }
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 2e26fcaf635b..9d0fd0b71852 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -53,7 +53,7 @@ enum {
         ATA_DNXFER_QUIET        = (1 << 31),
 };
 
-extern unsigned int ata_print_id;
+extern atomic_t ata_print_id;
 extern int atapi_passthru16;
 extern int libata_fua;
 extern int libata_noacpi;