I posted this yesterday but it seems people didn't understand the real
goal of my patch. So I will explain once more again:
This is a bugfix for loop.c block driver, as it currently allocates more
memory then it needs, without any further use.
If 'max_loop=255' parameter is given, the loop.c driver allocates this
amount of memory:
kmalloc(max_loop * sizeof(struct loop_device))
But in this case, (max_loop * sizeof) is greater than 65536, and thus
kmalloc must allocate the next bigger size (which is 128KB of RAM).
Unfortunately the loop.c driver doesn't allow users to use bigger
max_loop then 255 (for reasons which are completely obsolete) so the
rest of memory is *unused*.
This patch doesn't fix unused memory in the case of max_loop=255, but
rather it allows user to specify bigger max_loop (up to 455 on 386), so
the user can fully use all the memory, which would be allocated anyway.
Thank you for your consideration
Tomas M
slax.org
--- linux/drivers/block/loop.c_old 2007-03-23 14:27:04.000000000 +0000
+++ linux/drivers/block/loop.c 2007-03-23 14:31:18.098458759 +0000
@@ -1358,7 +1358,7 @@
* And now the modules code and kernel interface.
*/
module_param(max_loop, int, 0);
-MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (1-256)");
+MODULE_PARM_DESC(max_loop, "Maximum number of loop devices (455/355 on x86/x86_64)");
MODULE_LICENSE("GPL");
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
@@ -1402,9 +1402,9 @@
{
int i;
- if (max_loop < 1 || max_loop > 256) {
- printk(KERN_WARNING "loop: invalid max_loop (must be between"
- " 1 and 256), using default (8)\n");
+ if (max_loop < 1) {
+ printk(KERN_WARNING "loop: invalid max_loop (must be at least 1"
+ ", using default (8)\n");
max_loop = 8;
}
@@ -1465,7 +1465,7 @@
kfree(loop_dev);
out_mem1:
unregister_blkdev(LOOP_MAJOR, "loop");
- printk(KERN_ERR "loop: ran out of memory\n");
+ printk(KERN_ERR "loop: ran out of memory for max_loop=%d\n", max_loop);
return -ENOMEM;
}
