Re: bug 2400

[James Bottomley <James.Bottomley@steeleye.com>]

On Thu, 2004-04-01 at 18:32, James Bottomley wrote:
> Now, the questions are, whose issue is this and how do we fix it?  I can
> see that a driver needs early notification of unplugs so it can deny all
> access to a gone device.  On the other hand, for a user land open where
> we still have to hold resources in the driver, we'd like the driver to
> have a notify when the device reference count drops to zero so we can
> clean up.

OK, I think this is easily fixable in sr.c by moving around the release
code to do the right thing (and not drop the reference to sdev_gendev
until we're completely finished).

Jens, does this look OK (or have I just opened up another race window
somewhere else)?

James

===== drivers/scsi/sr.c 1.103 vs edited =====
--- 1.103/drivers/scsi/sr.c	Fri Apr  2 11:30:44 2004
+++ edited/drivers/scsi/sr.c	Fri Apr  2 17:29:06 2004
@@ -424,8 +424,19 @@
 
 static int sr_block_release(struct inode *inode, struct file *file)
 {
+	int ret;
 	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
-	return cdrom_release(&cd->cdi, file);
+	struct scsi_device *sdev = cd->device;
+	ret = cdrom_release(&cd->cdi, file);
+	if(ret)
+		return ret;
+	
+	unregister_cdrom(&cd->cdi);
+	kfree(cd);
+
+	scsi_device_put(sdev);
+
+	return 0;
 }
 
 static int sr_block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
@@ -500,7 +511,6 @@
 	if (cd->device->sector_size > 2048)
 		sr_set_blocklength(cd, 2048);
 
-	scsi_device_put(cd->device);
 }
 
 static int sr_probe(struct device *dev)
@@ -874,9 +884,6 @@
 	spin_unlock(&sr_index_lock);
 
 	put_disk(cd->disk);
-	unregister_cdrom(&cd->cdi);
-	kfree(cd);
-
 	return 0;
 }
 



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