[06/18] scsi: Use dummy inquiry data for the host device

Commit Message

Hannes Reinecke May 3, 2021, 3:03 p.m. UTC

Attach the dummy inquiry data to the scsi host device and use it
to check if any given device is a scsi host device.

Signed-off-by: Hannes Reinecke <[e-mail]>
---
 drivers/scsi/scsi_scan.c  | 17 +++++++++++++++--
 drivers/scsi/scsi_sysfs.c |  3 ++-
 include/scsi/scsi_host.h  |  7 ++++---
 3 files changed, 21 insertions(+), 6 deletions(-)

Comments

Bart Van Assche May 4, 2021, 2:52 a.m. UTC | #1

On 5/3/21 8:03 AM, Hannes Reinecke wrote:
> +/**
> + * scsi_device_is_host_dev - Check if a scsi device is a host device
> + * @sdev: SCSI device to test
> + *
> + * Returns: true if @sdev is a host device, false otherwise
> + */
> +bool scsi_device_is_host_dev(struct scsi_device *sdev)
> +{
> +	return ((const unsigned char *)sdev->inquiry == scsi_null_inquiry);
> +}

No parentheses around the expression in a return statement please.

> +EXPORT_SYMBOL_GPL(scsi_device_is_host_dev);

Does this mean that this function will be used outside the SCSI core?

Thanks,

Bart.

Hannes Reinecke May 4, 2021, 6:14 a.m. UTC | #2

On 5/4/21 4:52 AM, Bart Van Assche wrote:
> On 5/3/21 8:03 AM, Hannes Reinecke wrote:
>> +/**
>> + * scsi_device_is_host_dev - Check if a scsi device is a host device
>> + * @sdev: SCSI device to test
>> + *
>> + * Returns: true if @sdev is a host device, false otherwise
>> + */
>> +bool scsi_device_is_host_dev(struct scsi_device *sdev)
>> +{
>> +	return ((const unsigned char *)sdev->inquiry == scsi_null_inquiry);
>> +}
> 
> No parentheses around the expression in a return statement please.
> 
Okay.

>> +EXPORT_SYMBOL_GPL(scsi_device_is_host_dev);
> 
> Does this mean that this function will be used outside the SCSI core?
> 
Will have to check; might be a left-over from previous iterations.

Cheers,

Hannes

Patch

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index a50abba41ac1..55fa7f7317a2 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1940,9 +1940,11 @@  struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
 		goto out;
 
 	sdev = scsi_alloc_sdev(starget, 0, NULL);
-	if (sdev)
+	if (sdev) {
 		sdev->borken = 0;
-	else
+		sdev->inquiry = (unsigned char *)scsi_null_inquiry;
+		sdev->inquiry_len = sizeof(scsi_null_inquiry);
+	} else
 		scsi_target_reap(starget);
 	put_device(&starget->dev);
  out:
@@ -1967,3 +1969,14 @@  void scsi_free_host_dev(struct scsi_device *sdev)
 }
 EXPORT_SYMBOL(scsi_free_host_dev);
 
+/**
+ * scsi_device_is_host_dev - Check if a scsi device is a host device
+ * @sdev: SCSI device to test
+ *
+ * Returns: true if @sdev is a host device, false otherwise
+ */
+bool scsi_device_is_host_dev(struct scsi_device *sdev)
+{
+	return ((const unsigned char *)sdev->inquiry == scsi_null_inquiry);
+}
+EXPORT_SYMBOL_GPL(scsi_device_is_host_dev);
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 6d2a28294092..d5260d1b7b38 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -498,7 +498,8 @@  static void scsi_device_dev_release_usercontext(struct work_struct *work)
 		kfree_rcu(vpd_pg80, rcu);
 	if (vpd_pg89)
 		kfree_rcu(vpd_pg89, rcu);
-	kfree(sdev->inquiry);
+	if (!scsi_device_is_host_dev(sdev))
+		kfree(sdev->inquiry);
 	kfree(sdev);
 
 	if (parent)
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 3f3ebfdedeb2..f492e9034a62 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -804,14 +804,15 @@  void scsi_host_busy_iter(struct Scsi_Host *,
 struct class_container;
 
 /*
- * These two functions are used to allocate and free a pseudo device
- * which will connect to the host adapter itself rather than any
- * physical device.  You must deallocate when you are done with the
+ * These three functions are used to allocate, free, and test for
+ * a pseudo device which will connect to the host adapter itself rather
+ * than any physical device.  You must deallocate when you are done with the
  * thing.  This physical pseudo-device isn't real and won't be available
  * from any high-level drivers.
  */
 extern void scsi_free_host_dev(struct scsi_device *);
 extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
+bool scsi_device_is_host_dev(struct scsi_device *);
 
 /*
  * DIF defines the exchange of protection information between