Async scan changes -- now available as a git tree

I've put the asynchronous scsi scanning patches that I've been posting for a while into their own git tree, and split them in a way that I hope makes sense. Since git.kernel.org is experiencing some trouble right now, it's all available here:

http://git.parisc-linux.org/?p=linux-2.6.git;a=shortlog;h=scsi-async-scan

It started as a clone of scsi-misc. You can clone this tree via

git-fetch git://git.parisc-linux.org/git/linux-2.6.git \
scsi-async-scan:scsi-async-scan

I've had a bug report about the aic94xx, but:
<jejb> djwong, that can result because of the way libsas handles errors <jejb> I have a patch for that I should post

So I'm gleefully ignoring that problem for the moment.

Here's the commits currently in the tree:

commit 9b039f5f7d3ac3a3f1c97f2ef0d8b13690dcab12

Author: Matthew Wilcox <[email protected]>
Date:   Wed Nov 15 18:19:29 2006 -0500

[SCSI] Convert libata to use scsi_scan_host

This is a very rough conversion; each of the scsi_host_templates should be converted to add the new methods, but this is a good initial hack to check the concept works

commit b83c4572a79bb143d1d71c06a9765486a5daeff0

Author: Matthew Wilcox <[email protected]>
Date:   Wed Nov 15 18:17:41 2006 -0500

[SCSI] Convert aic94xx to use scsi_scan_host

Split up the init functions into the new scan_start and scan_finished methods

commit 114cf7c818ee1ba9104dbf0574c3b39e4f3ea5ef

Author: Matthew Wilcox <[email protected]>
Date:   Wed Nov 15 18:16:52 2006 -0500

[SCSI] Convert qla2xxx to use scsi_scan_host

Split up the init functions into the new scan_start and scan_finished methods

commit e7080cc397dc7f325c1d5154846f5bf071d5678c

Author: Matthew Wilcox <[email protected]>
Date:   Wed Nov 15 18:16:10 2006 -0500

[SCSI] Convert lpfc to use scsi_scan_host

Split up the init functions into the new scan_start and scan_finished methods

commit 59d1b29d6560c7b561116aa1556ffb829dbd3cff

Author: Matthew Wilcox <[email protected]>
Date:   Wed Nov 15 18:13:34 2006 -0500

[SCSI] Make scsi_scan_host work for drivers which find their own targets

If a driver can find its own targets, it can now fill in scan_finished and (optionally) scan_start in the scsi_host_template. Then, when it calls scsi_scan_host(), it will be called back (from a thread if asynchronous discovery is enabled), first to start the scan, and then at intervals to check if the scan is completed.

Also make scsi_prep_async_scan and scsi_finish_async_scan static.

commit 122bc8b3efa531cfa45d18335748ed39480d5363

Author: Matthew Wilcox <[email protected]>
Date:   Sun Oct 22 15:45:13 2006 -0600

SCSI: Missing check for no scanning

Drivers that called scsi_scan_tagrget() instead of scsi_scan_host() were still adding devices; this needs to be under the control of userspace, not the driver.

commit 9f752d4f48dbfe547cb7fe1a0e32dbd36a979137

Author: Matthew Wilcox <[email protected]>
Date:   Sun Oct 22 10:40:47 2006 -0600

Add Kconfig option for asynchronous SCSI scanning

To this point, the user has to add a kernel command line parameter to get asynchronous SCSI scanning. Now they can select the default at compile time and still override it at boot time if they need to.

OK, here's the error case fix I needed ...

James

Index: BUILD-2.6/drivers/scsi/libsas/sas_expander.c
===================================================================
@@ -597,10 +597,15 @@ static struct domain_device *sas_ex_disc
 	child->iproto = phy->attached_iproto;
 	memcpy(child->sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);
 	sas_hash_addr(child->hashed_sas_addr, child->sas_addr);
-	phy->port = sas_port_alloc(&parent->rphy->dev, phy_id);
-	BUG_ON(!phy->port);
-	/* FIXME: better error handling*/
-	BUG_ON(sas_port_add(phy->port) != 0);
+	if (!phy->port) {
+		phy->port = sas_port_alloc(&parent->rphy->dev, phy_id);
+		if (unlikely(!phy->port))
+			goto out_err;
+		if (unlikely(sas_port_add(phy->port) != 0)) {
+			sas_port_free(phy->port);
+			goto out_err;
+		}
+	}
 	sas_ex_get_linkrate(parent, child, phy);
 
 	if ((phy->attached_tproto & SAS_PROTO_STP) || phy->attached_sata_dev) {

@@ -615,8 +620,7 @@ static struct domain_device *sas_ex_disc
 			SAS_DPRINTK("report phy sata to %016llx:0x%x returned "
 				    "0x%x\n", SAS_ADDR(parent->sas_addr),
 				    phy_id, res);
-			kfree(child);
-			return NULL;
+			goto out_free;
 		}
 		memcpy(child->frame_rcvd, &child->sata_dev.rps_resp.rps.fis,
 		       sizeof(struct dev_to_host_fis));

@@ -627,14 +631,14 @@ static struct domain_device *sas_ex_disc
 				    "%016llx:0x%x returned 0x%x\n",
 				    SAS_ADDR(child->sas_addr),
 				    SAS_ADDR(parent->sas_addr), phy_id, res);
-			kfree(child);
-			return NULL;
+			goto out_free;
 		}
 	} else if (phy->attached_tproto & SAS_PROTO_SSP) {
 		child->dev_type = SAS_END_DEV;
 		rphy = sas_end_device_alloc(phy->port);
 		/* FIXME: error handling */
-		BUG_ON(!rphy);
+		if (unlikely(!rphy))
+			goto out_free;
 		child->tproto = phy->attached_tproto;
 		sas_init_dev(child);
 

@@ -651,9 +655,7 @@ static struct domain_device *sas_ex_disc
 				    "at %016llx:0x%x returned 0x%x\n",
 				    SAS_ADDR(child->sas_addr),
 				    SAS_ADDR(parent->sas_addr), phy_id, res);
-			/* FIXME: this kfrees list elements without removing them */
-			//kfree(child);
-			return NULL;
+			goto out_list_del;
 		}
 	} else {
 		SAS_DPRINTK("target proto 0x%x at %016llx:0x%x not handled\n",

@@ -663,6 +665,16 @@ static struct domain_device *sas_ex_disc
 
 	list_add_tail(&child->siblings, &parent_ex->children);
 	return child;
+
+ out_list_del:
+	list_del(&child->dev_list_node);
+	sas_rphy_free(rphy);
+ out_free:
+	sas_port_delete(phy->port);
+ out_err:
+	phy->port = NULL;
+	kfree(child);
+	return NULL;
 }
 
 static struct domain_device *sas_ex_discover_expander(

jejb: This is the patch in aic94xx-sas, correct?

willy: This patch was already applied to the kernel that I tested for you this morning, assuming that the answer to the previous question is "yes".

--D