Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/md/xor.c b/drivers/md/xor.c
new file mode 100644
index 0000000..324897c
--- /dev/null
+++ b/drivers/md/xor.c
@@ -0,0 +1,154 @@
+/*
+ * xor.c : Multiple Devices driver for Linux
+ *
+ * Copyright (C) 1996, 1997, 1998, 1999, 2000,
+ * Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.
+ *
+ * Dispatch optimized RAID-5 checksumming functions.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * You should have received a copy of the GNU General Public License
+ * (for example /usr/src/linux/COPYING); if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#define BH_TRACE 0
+#include <linux/module.h>
+#include <linux/raid/md.h>
+#include <linux/raid/xor.h>
+#include <asm/xor.h>
+
+/* The xor routines to use. */
+static struct xor_block_template *active_template;
+
+void
+xor_block(unsigned int count, unsigned int bytes, void **ptr)
+{
+ unsigned long *p0, *p1, *p2, *p3, *p4;
+
+ p0 = (unsigned long *) ptr[0];
+ p1 = (unsigned long *) ptr[1];
+ if (count == 2) {
+ active_template->do_2(bytes, p0, p1);
+ return;
+ }
+
+ p2 = (unsigned long *) ptr[2];
+ if (count == 3) {
+ active_template->do_3(bytes, p0, p1, p2);
+ return;
+ }
+
+ p3 = (unsigned long *) ptr[3];
+ if (count == 4) {
+ active_template->do_4(bytes, p0, p1, p2, p3);
+ return;
+ }
+
+ p4 = (unsigned long *) ptr[4];
+ active_template->do_5(bytes, p0, p1, p2, p3, p4);
+}
+
+/* Set of all registered templates. */
+static struct xor_block_template *template_list;
+
+#define BENCH_SIZE (PAGE_SIZE)
+
+static void
+do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
+{
+ int speed;
+ unsigned long now;
+ int i, count, max;
+
+ tmpl->next = template_list;
+ template_list = tmpl;
+
+ /*
+ * Count the number of XORs done during a whole jiffy, and use
+ * this to calculate the speed of checksumming. We use a 2-page
+ * allocation to have guaranteed color L1-cache layout.
+ */
+ max = 0;
+ for (i = 0; i < 5; i++) {
+ now = jiffies;
+ count = 0;
+ while (jiffies == now) {
+ mb();
+ tmpl->do_2(BENCH_SIZE, b1, b2);
+ mb();
+ count++;
+ mb();
+ }
+ if (count > max)
+ max = count;
+ }
+
+ speed = max * (HZ * BENCH_SIZE / 1024);
+ tmpl->speed = speed;
+
+ printk(" %-10s: %5d.%03d MB/sec\n", tmpl->name,
+ speed / 1000, speed % 1000);
+}
+
+static int
+calibrate_xor_block(void)
+{
+ void *b1, *b2;
+ struct xor_block_template *f, *fastest;
+
+ b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
+ if (! b1) {
+ printk("raid5: Yikes! No memory available.\n");
+ return -ENOMEM;
+ }
+ b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
+
+ /*
+ * If this arch/cpu has a short-circuited selection, don't loop through all
+ * the possible functions, just test the best one
+ */
+
+ fastest = NULL;
+
+#ifdef XOR_SELECT_TEMPLATE
+ fastest = XOR_SELECT_TEMPLATE(fastest);
+#endif
+
+#define xor_speed(templ) do_xor_speed((templ), b1, b2)
+
+ if (fastest) {
+ printk(KERN_INFO "raid5: automatically using best checksumming function: %s\n",
+ fastest->name);
+ xor_speed(fastest);
+ } else {
+ printk(KERN_INFO "raid5: measuring checksumming speed\n");
+ XOR_TRY_TEMPLATES;
+ fastest = template_list;
+ for (f = fastest; f; f = f->next)
+ if (f->speed > fastest->speed)
+ fastest = f;
+ }
+
+ printk("raid5: using function: %s (%d.%03d MB/sec)\n",
+ fastest->name, fastest->speed / 1000, fastest->speed % 1000);
+
+#undef xor_speed
+
+ free_pages((unsigned long)b1, 2);
+
+ active_template = fastest;
+ return 0;
+}
+
+static __exit void xor_exit(void) { }
+
+EXPORT_SYMBOL(xor_block);
+MODULE_LICENSE("GPL");
+
+module_init(calibrate_xor_block);
+module_exit(xor_exit);