Update the SCSI hosts module to use ida to manage its
host_no index instead of an ATOMIC integer. This means
that the SCSI host number will now be reclaimable.
Use the ida "simple" mechanism, since there should be no
need for a separate spin lock current usage. Ida was chosen
over idr because the hosts module already has its
own instance and locking mechanisms that aren't easily
changed.
Changes from v1:
* First version used regular ida routines
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Signed-off-by: Lee Duncan <lduncan@xxxxxxxx>
---
drivers/scsi/hosts.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 82ac1cd818ac..94025c5cf797 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -33,7 +33,7 @@
#include <linux/transport_class.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
-
+#include <linux/idr.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
@@ -42,7 +42,7 @@
#include "scsi_logging.h"
-static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */
+static DEFINE_IDA(host_index_ida);
static void scsi_host_cls_release(struct device *dev)
@@ -355,6 +355,8 @@ static void scsi_host_dev_release(struct device *dev)
kfree(shost->shost_data);
+ ida_simple_remove(&host_index_ida, shost->host_no);
+
if (parent)
put_device(parent);
kfree(shost);
@@ -388,6 +390,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
{
struct Scsi_Host *shost;
gfp_t gfp_mask = GFP_KERNEL;
+ int index;
if (sht->unchecked_isa_dma && privsize)
gfp_mask |= __GFP_DMA;
@@ -406,11 +409,11 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
init_waitqueue_head(&shost->host_wait);
mutex_init(&shost->scan_mutex);
- /*
- * subtract one because we increment first then return, but we need to
- * know what the next host number was before increment
- */
- shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
+ index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
+ if (index < 0)
+ goto fail_kfree;
+ shost->host_no = index;
+
shost->dma_channel = 0xff;
/* These three are default values which can be overridden */
@@ -495,7 +498,7 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
shost_printk(KERN_WARNING, shost,
"error handler thread failed to spawn, error = %ld\n",
PTR_ERR(shost->ehandler));
- goto fail_kfree;
+ goto fail_index_remove;
}
shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
@@ -511,6 +514,8 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
fail_kthread:
kthread_stop(shost->ehandler);
+ fail_index_remove:
+ ida_simple_remove(&host_index_ida, shost->host_no);
fail_kfree:
kfree(shost);
return NULL;
@@ -606,6 +611,7 @@ int scsi_init_hosts(void)
void scsi_exit_hosts(void)
{
class_unregister(&shost_class);
+ ida_destroy(&host_index_ida);
}
int scsi_is_host_device(const struct device *dev)
--
2.1.4
--
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