[PATCH 2.6.11.7] ATA-Over-Ethernet Root device

[McMullan, Jason]

This patch allows you to use ATA Over Ethernet as your root device,
with 'root=/dev/etherd/eX.Y/disc'

Limited testing, just for review.

Advantages:
	1) Ext3 over AOE caches dirents, so it's faster and less network
	   traffic than NFS root
	2) Smaller than NFS root code (for embedded systems)
	3) Proper locking semantics with Ext3, ReiserFS, etc.

-- 
Jason McMullan <jason.mcmullan@xxxxxxxxxxx>
TimeSys Corporation

Description: ATA Over Ethernet root device
	ie 'root=/dev/etherd/e0.0/disc' on the kernel command line
Signed-Off-By: Jason McMullan <jason.mcmullan@xxxxxxxxxxx>

--- linux-orig/drivers/block/Kconfig
+++ linux/drivers/block/Kconfig
@@ -506,4 +506,19 @@
 	This driver provides Support for ATA over Ethernet block
 	devices like the Coraid EtherDrive (R) Storage Blade.
 
+config ATA_OVER_ETH_ROOT
+	bool "ATA over Ethernet root device"
+	depends on ATA_OVER_ETH=y
+	help
+	  If you want to use ATA Over Ethernet as the root device,
+	  set this to 'y'
+
+config ATA_OVER_ETH_ROOT_SHELF
+	int "Shelf ID"
+	depends on ATA_OVER_ETH_ROOT
+	
+config ATA_OVER_ETH_ROOT_SLOT
+	int "Slot ID"
+	depends on ATA_OVER_ETH_ROOT
+
 endmenu
--- linux-orig/drivers/block/aoe/aoe.h
+++ linux/drivers/block/aoe/aoe.h
@@ -153,6 +153,7 @@
 int aoedev_init(void);
 void aoedev_exit(void);
 struct aoedev *aoedev_bymac(unsigned char *);
+struct aoedev *aoedev_bymajor_minor(ulong major, ulong minor);
 void aoedev_downdev(struct aoedev *d);
 struct aoedev *aoedev_set(ulong, unsigned char *, struct net_device *, ulong);
 int aoedev_busy(void);
--- linux-orig/drivers/block/aoe/aoeblk.c
+++ linux/drivers/block/aoe/aoeblk.c
@@ -229,6 +229,7 @@
 	gd->capacity = d->ssize;
 	snprintf(gd->disk_name, sizeof gd->disk_name, "etherd/e%ld.%ld",
 		d->aoemajor, d->aoeminor);
+	strncpy(gd->devfs_name, gd->disk_name, sizeof gd->devfs_name);
 
 	gd->queue = &d->blkq;
 	d->gd = gd;
--- linux-orig/drivers/block/aoe/aoedev.c
+++ linux/drivers/block/aoe/aoedev.c
@@ -28,6 +28,23 @@
 	return d;
 }
 
+struct aoedev *
+aoedev_bymajor_minor(ulong major, ulong minor)
+{
+	struct aoedev *d;
+	ulong flags;
+
+	spin_lock_irqsave(&devlist_lock, flags);
+
+	for (d=devlist; d; d=d->next)
+		if (d->aoemajor == major && d->aoeminor == minor)
+			break;
+
+	spin_unlock_irqrestore(&devlist_lock, flags);
+	return d;
+}
+
+
 /* called with devlist lock held */
 static struct aoedev *
 aoedev_newdev(ulong nframes)
--- linux-orig/drivers/block/aoe/aoemain.c
+++ linux/drivers/block/aoe/aoemain.c
@@ -7,6 +7,13 @@
 #include <linux/hdreg.h>
 #include <linux/blkdev.h>
 #include <linux/module.h>
+#include <linux/devfs_fs_kernel.h>
+#ifdef CONFIG_ATA_OVER_ETH_ROOT
+#include <linux/delay.h>
+#include <linux/rtnetlink.h>
+#include <linux/netdevice.h>
+#include <net/sock.h>
+#endif
 #include "aoe.h"
 
 MODULE_LICENSE("GPL");
@@ -53,6 +60,43 @@
 	}
 }
 
+#ifdef CONFIG_ATA_OVER_ETH_ROOT
+void aoe_root(unsigned long major, unsigned long minor)
+{
+	struct net_device *dev;
+
+	printk(KERN_INFO
+		"aoe: Waiting for root AOE device e%ld.%ld\n", major, minor);
+
+	/* Give hardware a chance to settle */
+	msleep(500);
+
+	rtnl_shlock();
+	/* bring loopback device up first */
+printk("Bring up loopback...\n");
+	if (dev_change_flags(&loopback_dev, loopback_dev.flags | IFF_UP) < 0)
+		printk(KERN_ERR "AOE Root: Failed to open %s\n", loopback_dev.name);
+
+	/* Setup all network devices */
+	for (dev = dev_base; dev ; dev = dev->next) {
+		if (dev == &loopback_dev)
+			continue;
+printk("Bring up %s...\n",dev->name);
+		dev_change_flags(dev, dev->flags | IFF_UP);
+	}
+	rtnl_shunlock();
+
+	/* Give drivers a chance to settle */
+	ssleep(1);
+
+	do {
+		aoecmd_cfg(major, minor);
+		msleep(1);
+	} while (!aoedev_bymajor_minor(CONFIG_ATA_OVER_ETH_ROOT_SHELF,CONFIG_ATA_OVER_ETH_ROOT_SLOT));
+
+}
+#endif
+
 static void
 aoe_exit(void)
 {
@@ -63,6 +107,7 @@
 	aoechr_exit();
 	aoedev_exit();
 	aoeblk_exit();		/* free cache after de-allocating bufs */
+	devfs_remove("etherd");
 }
 
 static int __init
@@ -70,6 +115,8 @@
 {
 	int ret;
 
+	devfs_mk_dir("etherd");
+	        
 	ret = aoedev_init();
 	if (ret)
 		return ret;
@@ -91,6 +138,9 @@
 	printk(KERN_INFO
 	       "aoe: aoe_init: AoE v2.6-%s initialised.\n",
 	       VERSION);
+#ifdef CONFIG_ATA_OVER_ETH_ROOT
+	aoe_root(CONFIG_ATA_OVER_ETH_ROOT_SHELF,CONFIG_ATA_OVER_ETH_ROOT_SLOT);
+#endif
 	discover_timer(TINIT);
 	return 0;
 
@@ -102,6 +152,7 @@
 	aoechr_exit();
  chr_fail:
 	aoedev_exit();
+	devfs_remove("etherd");
 	
 	printk(KERN_INFO "aoe: aoe_init: initialisation failure.\n");
 	return ret;

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