Re: [BK PATCH] SCSI host num allocation improvement

Ben Collins
2004-02-27T03:05:27Z

Here's one that actually compiles.

===== drivers/scsi/hosts.c 1.96 vs edited =====
--- 1.96/drivers/scsi/hosts.c Mon Dec 29 16:38:10 2003
+++ edited/drivers/scsi/hosts.c Thu Feb 26 22:00:33 2004
@@ -30,6 +30,7 @@
#include <linux/list.h>
#include <linux/completion.h>
#include <linux/unistd.h>
+#include <linux/idr.h>

#include <scsi/scsi_host.h>
#include "scsi.h"
@@ -37,12 +38,15 @@
#include "scsi_priv.h"
#include "scsi_logging.h"

-
-static int scsi_host_next_hn; /* host_no for next new host */
+static DECLARE_MUTEX(host_num_lock);
+static struct idr allocated_hosts;

static void scsi_host_cls_release(struct class_device *class_dev)
{
+ down(&host_num_lock);
+ idr_remove(&allocated_hosts, class_to_shost(class_dev)->host_no);
+ up(&host_num_lock);
put_device(&class_to_shost(class_dev)->shost_gendev);
}

@@ -166,6 +170,7 @@
kfree(shost);
}

+
/**
* scsi_host_alloc - register a scsi host adapter instance.
* @sht: pointer to scsi host template
@@ -214,7 +219,6 @@

init_MUTEX(&shost->scan_mutex);

- shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
shost->dma_channel = 0xff;

/* These three are default values which can be overridden */
@@ -263,6 +267,11 @@
if (rval)
goto fail_kfree;

+ down(&host_num_lock);
+ idr_pre_get(&allocated_hosts, GFP_KERNEL);
+ shost->host_no = idr_get_new(&allocated_hosts, NULL);
+ up(&host_num_lock);
+
device_initialize(&shost->shost_gendev);
snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
shost->host_no);
@@ -307,6 +316,9 @@

void scsi_unregister(struct Scsi_Host *shost)
{
+ down(&host_num_lock);
+ idr_remove(&allocated_hosts, shost->host_no);
+ up(&host_num_lock);
list_del(&shost->sht_legacy_list);
scsi_host_put(shost);
}
@@ -361,6 +373,7 @@

int scsi_init_hosts(void)
{
+ idr_init(&allocated_hosts);
return class_register(&shost_class);
}

--
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