SCSI fixes on 20210613

Four reasonably small fixes to the core for scsi host allocation
 failure paths.  The root problem is that we're not freeing the memory
 allocated by dev_set_name(), which involves a rejig of may of the free
 on error paths to do put_device() instead of kfree which, in turn, has
 several other knock on ramifications and inspection turned up a few
 other lurking bugs.
 
 Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>
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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "Four reasonably small fixes to the core for scsi host allocation
  failure paths.

  The root problem is that we're not freeing the memory allocated by
  dev_set_name(), which involves a rejig of may of the free on error
  paths to do put_device() instead of kfree which, in turn, has several
  other knock on ramifications and inspection turned up a few other
  lurking bugs"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: core: Only put parent device if host state differs from SHOST_CREATED
  scsi: core: Put .shost_dev in failure path if host state changes to RUNNING
  scsi: core: Fix failure handling of scsi_add_host_with_dma()
  scsi: core: Fix error handling of scsi_host_alloc()

drivers/scsi/hosts.c

@@ -254,12 +254,11 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 
 	device_enable_async_suspend(&shost->shost_dev);
 
+	get_device(&shost->shost_gendev);
 	error = device_add(&shost->shost_dev);
 	if (error)
 		goto out_del_gendev;
 
-	get_device(&shost->shost_gendev);
-
 	if (shost->transportt->host_size) {
 		shost->shost_data = kzalloc(shost->transportt->host_size,
 					 GFP_KERNEL);
@@ -278,33 +277,36 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 
 		if (!shost->work_q) {
 			error = -EINVAL;
-			goto out_free_shost_data;
+			goto out_del_dev;
 		}
 	}
 
 	error = scsi_sysfs_add_host(shost);
 	if (error)
-		goto out_destroy_host;
+		goto out_del_dev;
 
 	scsi_proc_host_add(shost);
 	scsi_autopm_put_host(shost);
 	return error;
 
- out_destroy_host:
+	/*
-	if (shost->work_q)
+	 * Any host allocation in this function will be freed in
-		destroy_workqueue(shost->work_q);
+	 * scsi_host_dev_release().
- out_free_shost_data:
+	 */
-	kfree(shost->shost_data);
  out_del_dev:
 	device_del(&shost->shost_dev);
  out_del_gendev:
+	/*
+	 * Host state is SHOST_RUNNING so we have to explicitly release
+	 * ->shost_dev.
+	 */
+	put_device(&shost->shost_dev);
 	device_del(&shost->shost_gendev);
  out_disable_runtime_pm:
 	device_disable_async_suspend(&shost->shost_gendev);
 	pm_runtime_disable(&shost->shost_gendev);
 	pm_runtime_set_suspended(&shost->shost_gendev);
 	pm_runtime_put_noidle(&shost->shost_gendev);
-	scsi_mq_destroy_tags(shost);
  fail:
 	return error;
 }
@@ -345,7 +347,7 @@ static void scsi_host_dev_release(struct device *dev)
 
 	ida_simple_remove(&host_index_ida, shost->host_no);
 
-	if (parent)
+	if (shost->shost_state != SHOST_CREATED)
 		put_device(parent);
 	kfree(shost);
 }
@@ -388,8 +390,10 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	mutex_init(&shost->scan_mutex);
 
 	index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
-	if (index < 0)
+	if (index < 0) {
-		goto fail_kfree;
+		kfree(shost);
+		return NULL;
+	}
 	shost->host_no = index;
 
 	shost->dma_channel = 0xff;
@@ -481,7 +485,7 @@ 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_index_remove;
+		goto fail;
 	}
 
 	shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
@@ -490,17 +494,18 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 	if (!shost->tmf_work_q) {
 		shost_printk(KERN_WARNING, shost,
 			     "failed to create tmf workq\n");
-		goto fail_kthread;
+		goto fail;
 	}
 	scsi_proc_hostdir_add(shost->hostt);
 	return shost;
+ fail:
+	/*
+	 * Host state is still SHOST_CREATED and that is enough to release
+	 * ->shost_gendev. scsi_host_dev_release() will free
+	 * dev_name(&shost->shost_dev).
+	 */
+	put_device(&shost->shost_gendev);
 
- fail_kthread:
-	kthread_stop(shost->ehandler);
- fail_index_remove:
-	ida_simple_remove(&host_index_ida, shost->host_no);
- fail_kfree:
-	kfree(shost);
 	return NULL;
 }
 EXPORT_SYMBOL(scsi_host_alloc);