Re: 1GB/2GB/3GB User Space Splitting Patch 2.6.8.1 (PSEUDO SPAM)

["Randy.Dunlap" <rddunlap@osdl.org>]

On Mon, 30 Aug 2004 05:56:17 +0000 jmerkey@comcast.net wrote:

| 
| 
| 
| 
| > What kernel version?  I can't even find usb_read_device() in 2.6.9-rc1.
| > 
| > BTW, as someone else requested, please teach your mail client to wrap
| > lines around column 70-72.  Thanks.
| > 
| > ~Randy
| 
| linux-2.6.8.1.tar.gz


usb_device_read here (usb_read_device above :)


| static ssize_t usb_device_read(struct file *file, 
|                                                          char __user *buf, 
|                                                          size_t nbytes, 
|                                                          loff_t *ppos)
| {
|         struct list_head *buslist;
|         struct usb_bus *bus;
|         ssize_t ret, total_written = 0;
|         loff_t skip_bytes = *ppos;
|                                                                                 
|         if (*ppos < 0)
|                 return -EINVAL;
|         if (nbytes <= 0)
|                 return 0;
|         if (!access_ok(VERIFY_WRITE, buf, nbytes))
|                 return -EFAULT;
|                                                                                 
|         /* enumerate busses */
|         down (&usb_bus_list_lock);
|         for (buslist = usb_bus_list.next; 
|                buslist != &usb_bus_list; 
|                buslist = buslist->next) {
|                 /* print devices for this bus */
|                 bus = list_entry(buslist, struct usb_bus, 
|                                              bus_list);
|                 /* print devices for this bus */
|                 bus = list_entry(buslist, struct usb_bus, 
|                                              bus_list);
|                                                                                 
|                 /* recurse through all children of the root hub */
|                 if (!bus->root_hub)
|                         continue;
| 
| // IT BARFS RIGHT HERE -->
|                 down(&bus->root_hub->serialize);

It doesn't barf on me.  I added one other patch on top of yours:
one from Roland Dreier, for arch/i386/kernel/doublefault.c [below].

| P.S.  I am using my comcast account which
| is not as good as MUTT -- line wrap settings
| since it is web based.  
| drdos.com gets rejected
| so I am typing less characters/line. :-)
| -
Thanks.

--
~Randy



Looks like arch/i386/kernel/doublefault.c is one place in the code
that hardcodes the assumption that PAGE_OFFSET == 0xC0000000.  Here's
a patch that fixes that.

(Of course this doesn't really fix anything except debugging output)

 - Roland

Signed-off-by: Roland Dreier <roland@topspin.com>

Index: linux-2.6.8-rc1/arch/i386/kernel/doublefault.c
===================================================================
--- linux-2.6.8-rc1.orig/arch/i386/kernel/doublefault.c
+++ linux-2.6.8-rc1/arch/i386/kernel/doublefault.c
@@ -13,7 +13,7 @@
 static unsigned long doublefault_stack[DOUBLEFAULT_STACKSIZE];
 #define STACK_START (unsigned long)(doublefault_stack+DOUBLEFAULT_STACKSIZE)
 
-#define ptr_ok(x) ((x) > 0xc0000000 && (x) < 0xc1000000)
+#define ptr_ok(x) ((x) > PAGE_OFFSET && (x) < PAGE_OFFSET + 0x1000000)
 
 static void doublefault_fn(void)
 {
-