Commit 126a4fe0 authored by Lee Duncan's avatar Lee Duncan Committed by Martin K. Petersen
Browse files

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: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarLee Duncan <lduncan@suse.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent d92ca9d3

drivers/scsi/hosts.c

+14 −8
Original line number Diff line number Diff line
@@ -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)

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