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Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 20 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.552543146@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* xor.c : Multiple Devices driver for Linux
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*
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* Copyright (C) 1996, 1997, 1998, 1999, 2000,
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* Ingo Molnar, Matti Aarnio, Jakub Jelinek, Richard Henderson.
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*
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* Dispatch optimized RAID-5 checksumming functions.
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*/
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#define BH_TRACE 0
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <linux/raid/xor.h>
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#include <linux/jiffies.h>
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#include <linux/preempt.h>
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#include <asm/xor.h>
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#ifndef XOR_SELECT_TEMPLATE
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#define XOR_SELECT_TEMPLATE(x) (x)
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#endif
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/* The xor routines to use. */
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static struct xor_block_template *active_template;
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void
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xor_blocks(unsigned int src_count, unsigned int bytes, void *dest, void **srcs)
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{
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unsigned long *p1, *p2, *p3, *p4;
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p1 = (unsigned long *) srcs[0];
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if (src_count == 1) {
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active_template->do_2(bytes, dest, p1);
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return;
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}
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p2 = (unsigned long *) srcs[1];
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if (src_count == 2) {
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active_template->do_3(bytes, dest, p1, p2);
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return;
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}
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p3 = (unsigned long *) srcs[2];
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if (src_count == 3) {
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active_template->do_4(bytes, dest, p1, p2, p3);
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return;
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}
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p4 = (unsigned long *) srcs[3];
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active_template->do_5(bytes, dest, p1, p2, p3, p4);
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}
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EXPORT_SYMBOL(xor_blocks);
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/* Set of all registered templates. */
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static struct xor_block_template *__initdata template_list;
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#define BENCH_SIZE (PAGE_SIZE)
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static void __init
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do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2)
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{
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int speed;
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unsigned long now, j;
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int i, count, max;
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tmpl->next = template_list;
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template_list = tmpl;
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preempt_disable();
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/*
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* Count the number of XORs done during a whole jiffy, and use
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* this to calculate the speed of checksumming. We use a 2-page
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* allocation to have guaranteed color L1-cache layout.
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*/
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max = 0;
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for (i = 0; i < 5; i++) {
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j = jiffies;
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count = 0;
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while ((now = jiffies) == j)
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cpu_relax();
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while (time_before(jiffies, now + 1)) {
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mb(); /* prevent loop optimzation */
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tmpl->do_2(BENCH_SIZE, b1, b2);
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mb();
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count++;
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mb();
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}
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if (count > max)
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max = count;
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}
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preempt_enable();
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speed = max * (HZ * BENCH_SIZE / 1024);
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tmpl->speed = speed;
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printk(KERN_INFO " %-10s: %5d.%03d MB/sec\n", tmpl->name,
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speed / 1000, speed % 1000);
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}
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static int __init
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calibrate_xor_blocks(void)
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{
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void *b1, *b2;
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struct xor_block_template *f, *fastest;
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fastest = XOR_SELECT_TEMPLATE(NULL);
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if (fastest) {
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printk(KERN_INFO "xor: automatically using best "
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"checksumming function %-10s\n",
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fastest->name);
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goto out;
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}
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b1 = (void *) __get_free_pages(GFP_KERNEL, 2);
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if (!b1) {
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printk(KERN_WARNING "xor: Yikes! No memory available.\n");
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return -ENOMEM;
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}
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b2 = b1 + 2*PAGE_SIZE + BENCH_SIZE;
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/*
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* If this arch/cpu has a short-circuited selection, don't loop through
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* all the possible functions, just test the best one
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*/
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#define xor_speed(templ) do_xor_speed((templ), b1, b2)
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printk(KERN_INFO "xor: measuring software checksum speed\n");
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XOR_TRY_TEMPLATES;
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fastest = template_list;
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for (f = fastest; f; f = f->next)
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if (f->speed > fastest->speed)
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fastest = f;
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printk(KERN_INFO "xor: using function: %s (%d.%03d MB/sec)\n",
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fastest->name, fastest->speed / 1000, fastest->speed % 1000);
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#undef xor_speed
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free_pages((unsigned long)b1, 2);
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out:
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active_template = fastest;
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return 0;
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}
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static __exit void xor_exit(void) { }
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MODULE_LICENSE("GPL");
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/* when built-in xor.o must initialize before drivers/md/md.o */
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core_initcall(calibrate_xor_blocks);
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module_exit(xor_exit);
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