On Wed, 2015-10-07 at 16:51 -0700, Lee Duncan wrote:
> Update the SCSI hosts module to use the ida_simple*() routines
> to manage its host_no index instead of an ATOMIC integer. This
> means that the SCSI host number will now be reclaimable.
>
> 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 8bb173e01084..b6a5ffa886b7 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)
> @@ -337,6 +337,8 @@ 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);
> @@ -370,6 +372,7 @@ 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;
> @@ -388,11 +391,11 @@ 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 */
> @@ -477,7 +480,7 @@ 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",
> @@ -493,6 +496,8 @@ 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;
> @@ -588,6 +593,7 @@ 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)
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
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