1 files changed, 154 insertions, 0 deletions

diff --git a/drivers/md/xor.c b/drivers/md/xor.c
new file mode 100644
index 000000000000..324897c4be4e
--- /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);