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scsi: Use ida for host number management 

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.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
hifive-unleashed-5.1
Lee Duncan 2016-01-20 11:48:00 -08:00 committed by Martin K. Petersen
parent d92ca9d3de
commit 126a4fe010
1 changed files with 14 additions and 8 deletions
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22
drivers/scsi/hosts.c
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@ -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)