From: Tomas Henzl <thenzl@redhat.com>
Date: Sun, 29 Aug 2010 15:49:41 -0400
Subject: [block] cciss: factor out scatter gather alloc and free
Message-id: <1283097002-3341-43-git-send-email-thenzl@redhat.com>
Patchwork-id: 27904
O-Subject: [RHEL6 PATCH 42/63] cciss: factor out scatter gather allocation and
	freeing
Bugzilla: 568830
RH-Acked-by: Neil Horman <nhorman@redhat.com>

Factor out scatter gather chain block allocation and freeing
Rationale is that I want to use this code from the scsi half of the
driver.

diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 600dfd9..669cac5 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -247,6 +247,59 @@ static void log_unit_to_scsi3addr(ctlr_info_t *h, unsigned char scsi3addr[],
 		sizeof(h->drv[log_unit]->LunID));
 }
 
+static void cciss_free_sg_chain_blocks(struct Cmd_sg_list **cmd_sg_list,
+	int nr_cmds)
+{
+	int i;
+
+	if (!cmd_sg_list)
+		return;
+	for (i = 0; i < nr_cmds; i++) {
+		if (cmd_sg_list[i]) {
+			kfree(cmd_sg_list[i]->sgchain);
+			kfree(cmd_sg_list[i]);
+			cmd_sg_list[i] = NULL;
+		}
+	}
+	kfree(cmd_sg_list);
+}
+
+static struct Cmd_sg_list **cciss_allocate_sg_chain_blocks(ctlr_info_t *h,
+	int chainsize, int nr_cmds)
+{
+	int j;
+	struct Cmd_sg_list **cmd_sg_list;
+
+	if (chainsize <= 0)
+		return NULL;
+
+	cmd_sg_list = kmalloc(sizeof(*cmd_sg_list) * nr_cmds, GFP_KERNEL);
+	if (!cmd_sg_list)
+		return NULL;
+
+	/* Build up chain blocks for each command */
+	for (j = 0; j < nr_cmds; j++) {
+		cmd_sg_list[j] = kmalloc(sizeof(*cmd_sg_list[j]), GFP_KERNEL);
+		if (!cmd_sg_list[j]) {
+			dev_err(&h->pdev->dev, "Cannot get memory "
+				"for chain block.\n");
+			goto clean;
+		}
+		/* Need a block of chainsized s/g elements. */
+		cmd_sg_list[j]->sgchain = kmalloc((chainsize *
+			sizeof(SGDescriptor_struct)), GFP_KERNEL);
+		if (!cmd_sg_list[j]->sgchain) {
+			dev_err(&h->pdev->dev, "Cannot get memory "
+				"for s/g chains.\n");
+			goto clean;
+		}
+	}
+	return cmd_sg_list;
+clean:
+	cciss_free_sg_chain_blocks(cmd_sg_list, nr_cmds);
+	return NULL;
+}
+
 #include "cciss_scsi.c"		/* For SCSI tape support */
 
 #ifdef CONFIG_PROC_FS
@@ -4160,37 +4213,10 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
 			goto clean4;
 		}
 	}
-	hba[i]->cmd_sg_list = kmalloc(sizeof(struct Cmd_sg_list *) *
-						hba[i]->nr_cmds,
-						GFP_KERNEL);
-	if (!hba[i]->cmd_sg_list) {
-		printk(KERN_ERR "cciss%d: Cannot get memory for "
-			"s/g chaining.\n", i);
+	hba[i]->cmd_sg_list = cciss_allocate_sg_chain_blocks(hba[i],
+		hba[i]->chainsize, hba[i]->nr_cmds);
+	if (!hba[i]->cmd_sg_list && hba[i]->chainsize > 0)
 		goto clean4;
-	}
-	/* Build up chain blocks for each command */
-	if (hba[i]->chainsize > 0) {
-		for (j = 0; j < hba[i]->nr_cmds; j++) {
-			hba[i]->cmd_sg_list[j] =
-					kmalloc(sizeof(struct Cmd_sg_list),
-							GFP_KERNEL);
-			if (!hba[i]->cmd_sg_list[j]) {
-				printk(KERN_ERR "cciss%d: Cannot get memory "
-					"for chain block.\n", i);
-				goto clean4;
-			}
-			/* Need a block of chainsized s/g elements. */
-			hba[i]->cmd_sg_list[j]->sgchain =
-					kmalloc((hba[i]->chainsize *
-						sizeof(SGDescriptor_struct)),
-						GFP_KERNEL);
-			if (!hba[i]->cmd_sg_list[j]->sgchain) {
-				printk(KERN_ERR "cciss%d: Cannot get memory "
-					"for s/g chains\n", i);
-				goto clean4;
-			}
-		}
-	}
 
 	spin_lock_init(&hba[i]->lock);
 
@@ -4248,17 +4274,7 @@ clean4:
 	for (k = 0; k < hba[i]->nr_cmds; k++)
 		kfree(hba[i]->scatter_list[k]);
 	kfree(hba[i]->scatter_list);
-	/* Only tear down of controller supports > 31 */
-	if (hba[i]->chainsize > 0) {
-		for (j = 0; j < hba[i]->nr_cmds; j++) {
-			if (hba[i]->cmd_sg_list[j]) {
-				kfree(hba[i]->cmd_sg_list[j]->sgchain);
-				kfree(hba[i]->cmd_sg_list[j]);
-			}
-		}
-		kfree(hba[i]->cmd_sg_list);
-	}
-
+	cciss_free_sg_chain_blocks(hba[i]->cmd_sg_list, hba[i]->nr_cmds);
 	if (hba[i]->cmd_pool)
 		pci_free_consistent(hba[i]->pdev,
 				    hba[i]->nr_cmds * sizeof(CommandList_struct),
@@ -4376,16 +4392,7 @@ static void __devexit cciss_remove_one(struct pci_dev *pdev)
 	for (j = 0; j < hba[i]->nr_cmds; j++)
 		kfree(hba[i]->scatter_list[j]);
 	kfree(hba[i]->scatter_list);
-	/* Only tear down of controller supports > 31 */
-	if (hba[i]->chainsize > 0) {
-		for (j = 0; j < hba[i]->nr_cmds; j++) {
-			if (hba[i]->cmd_sg_list[j]) {
-				kfree(hba[i]->cmd_sg_list[j]->sgchain);
-				kfree(hba[i]->cmd_sg_list[j]);
-			}
-		}
-		kfree(hba[i]->cmd_sg_list);
-	}
+	cciss_free_sg_chain_blocks(hba[i]->cmd_sg_list, hba[i]->nr_cmds);
 	/*
 	 * Deliberately omit pci_disable_device(): it does something nasty to
 	 * Smart Array controllers that pci_enable_device does not undo