how to use scsi_remove_device

Hi all,

the following drivers use [__]scsi_add_device/ scsi_remove_device:

drivers/ieee1394/sbp2.c
drivers/message/i2o/i2o_scsi.c
drivers/message/fusion/mptsas.c
drivers/scsi/aacraid/commsup.c
drivers/scsi/ipr.c

Sbp2 calls scsi_add_device + scsi_remove_device.
I2o_scsi calls __scsi_add_device + scsi_remove_device + scsi_device_put. Ipr calls scsi_add_device + scsi_device_get + scsi_remove_device + scsi_device_put.

But aacraid and mptsas call scsi_add_device + scsi_remove_device + scsi_device_put. AFAICS this is either one scsi_device_put too many or one scsi_device_get too few.

(I am looking at Linus' tree.)

Stefan Richter
-=====-=-==- --== =---=
http://arcgraph.de/sr/

I copied Mark Salyzyn since he is the aacraid driver writer.

Looking at commsup.c, though, I think that the scsi_device_put is done after the scsi_device_lookup only if the scsi_device_remove is not done.

Mark.

Mark Haverkamp <[email protected]>

...

...

Yes, the scsi_device_put is correct since scsi_device_lookup took a reference.

Stefan Richter
-=====-=-==- --== =--==
http://arcgraph.de/sr/

The rule is that scsi_add_device() doesn't leave you with a reference, but __scsi_add_device() does.

scsi_remove_device() does just that, but it doesn't put any references you might have taken separately.

These all look correct. The scsi_device_puts are paired with scsi_device_lookup() which does indeed get a reference which needs putting.

James

Hello all,

I was just searching the linux-scsi mailing list and noticed this in-progress hotplug patch for the libata SATA framework, which in turn uses the SCSI layers.

In particular notice the lookup of the scsi_device before it scsi_remove_device(), then scsi_device_put().

In my particular case (Marvell's GPL'd SATA driver, not the libata one) *it seems* the device lookup is missing, although I have to do more work to verify this statement.

Regards,

Leon.

+void ata_scsi_hot_plug(struct ata_port *ap, unsigned int device) +{
+ /* libata uses the 'id' or 'target' value */
+ scsi_add_device(ap->host, 0, device, 0);
+}
+

+void ata_scsi_hot_unplug(struct ata_port *ap, unsigned int device) +{
+ /* libata uses the 'id' or 'target' value */
+ struct scsi_device *scd = scsi_device_lookup(ap->host, 0, device, 0);
+
+ /* Make sure that we set this here, in case we aren't called as a
+ * result of sata_hot_unplug */
+ ap->device[device].class = ATA_DEV_NONE;
+
+ if (scd) /* Set to cancel state to block further I/O */
+ scsi_device_set_state(scd, SDEV_CANCEL);
+
+ /* We might have a pending qc on I/O to a removed device. */
+ ata_check_kill_qc(ap, device);
+
+ if (scd) {
+ scsi_remove_device(scd);
+ scsi_device_put(scd);
+ }
+}