Commit 3ed78972 authored Jun 11, 2008 by Mike Christie Committed by James Bottomley Jun 15, 2008

[SCSI] scsi_host regression: fix scsi host leak



commit 9c770108
Author: Dave Young <hidave.darkstar@gmail.com>
Date:   Tue Jan 22 14:01:34 2008 +0800

    scsi: use class iteration api

Isn't a correct replacement for the original hand rolled host
lookup. The problem is that class_find_child would get a reference to
the host's class device which is never released.  Since the host class
device holds a reference to the host gendev, the host can never be
freed.

In 2.6.26 we started using class_find_device, and this function also
gets a reference to the device, so we end up with an extra ref
and the host will not get released.

This patch adds a put_device to balance the class_find_device() get. I
kept the scsi_host_get in scsi_host_lookup, because the target layer
is using scsi_host_lookup and it looks like it needs the SHOST_DEL
check.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

parent d1daeabf

drivers/scsi/hosts.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -456,6 +456,10 @@ static int __scsi_host_match(struct device dev, void data)
		*
		* Return value:
		* A pointer to located Scsi_Host or NULL.
		*
		* The caller must do a scsi_host_put() to drop the reference
		* that scsi_host_get() took. The put_device() below dropped
		* the reference from class_find_device().
		**/
		struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
		{
		@@ -463,9 +467,10 @@ struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
		struct Scsi_Host *shost = ERR_PTR(-ENXIO);

		cdev = class_find_device(&shost_class, &hostnum, __scsi_host_match);
		if (cdev)
		if (cdev) {
		shost = scsi_host_get(class_to_shost(cdev));

		put_device(cdev);
		}
		return shost;
		}
		EXPORT_SYMBOL(scsi_host_lookup);

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