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linux-xiaomi-chiron/drivers/mtd/tests/stresstest.c
Jason A. Donenfeld 81895a65ec treewide: use prandom_u32_max() when possible, part 1 
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

-       RAND = get_random_u32();
        ... when != RAND
-       RAND %= (E);
+       RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
        print("Skipping 0x%x for cleanup elsewhere" % (value))
        cocci.include_match(False)
elif value & (value + 1) != 0:
        print("Skipping 0x%x because it's not a power of two minus one" % (value))
        cocci.include_match(False)
elif literal.startswith('0x'):
        coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
        coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

 {
-       T VAR;
-       VAR = (E);
-       return VAR;
+       return E;
 }

@drop_var@
type T;
identifier VAR;
@@

 {
-       T VAR;
        ... when != VAR
 }

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:55 -06:00

232 lines
4.9 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2006-2008 Nokia Corporation
*
* Test random reads, writes and erases on MTD device.
*
* Author: Adrian Hunter <ext-adrian.hunter@nokia.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/err.h>
#include <linux/mtd/mtd.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
#include <linux/random.h>
#include "mtd_test.h"
static int dev = -EINVAL;
module_param(dev, int, S_IRUGO);
MODULE_PARM_DESC(dev, "MTD device number to use");
static int count = 10000;
module_param(count, int, S_IRUGO);
MODULE_PARM_DESC(count, "Number of operations to do (default is 10000)");
static struct mtd_info *mtd;
static unsigned char *writebuf;
static unsigned char *readbuf;
static unsigned char *bbt;
static int *offsets;
static int pgsize;
static int bufsize;
static int ebcnt;
static int pgcnt;
static int rand_eb(void)
{
unsigned int eb;
again:
/* Read or write up 2 eraseblocks at a time - hence 'ebcnt - 1' */
eb = prandom_u32_max(ebcnt - 1);
if (bbt[eb])
goto again;
return eb;
}
static int rand_offs(void)
{
return prandom_u32_max(bufsize);
}
static int rand_len(int offs)
{
return prandom_u32_max(bufsize - offs);
}
static int do_read(void)
{
int eb = rand_eb();
int offs = rand_offs();
int len = rand_len(offs);
loff_t addr;
if (bbt[eb + 1]) {
if (offs >= mtd->erasesize)
offs -= mtd->erasesize;
if (offs + len > mtd->erasesize)
len = mtd->erasesize - offs;
}
addr = (loff_t)eb * mtd->erasesize + offs;
return mtdtest_read(mtd, addr, len, readbuf);
}
static int do_write(void)
{
int eb = rand_eb(), offs, err, len;
loff_t addr;
offs = offsets[eb];
if (offs >= mtd->erasesize) {
err = mtdtest_erase_eraseblock(mtd, eb);
if (err)
return err;
offs = offsets[eb] = 0;
}
len = rand_len(offs);
len = ((len + pgsize - 1) / pgsize) * pgsize;
if (offs + len > mtd->erasesize) {
if (bbt[eb + 1])
len = mtd->erasesize - offs;
else {
err = mtdtest_erase_eraseblock(mtd, eb + 1);
if (err)
return err;
offsets[eb + 1] = 0;
}
}
addr = (loff_t)eb * mtd->erasesize + offs;
err = mtdtest_write(mtd, addr, len, writebuf);
if (unlikely(err))
return err;
offs += len;
while (offs > mtd->erasesize) {
offsets[eb++] = mtd->erasesize;
offs -= mtd->erasesize;
}
offsets[eb] = offs;
return 0;
}
static int do_operation(void)
{
if (prandom_u32_max(2))
return do_read();
else
return do_write();
}
static int __init mtd_stresstest_init(void)
{
int err;
int i, op;
uint64_t tmp;
printk(KERN_INFO "\n");
printk(KERN_INFO "=================================================\n");
if (dev < 0) {
pr_info("Please specify a valid mtd-device via module parameter\n");
pr_crit("CAREFUL: This test wipes all data on the specified MTD device!\n");
return -EINVAL;
}
pr_info("MTD device: %d\n", dev);
mtd = get_mtd_device(NULL, dev);
if (IS_ERR(mtd)) {
err = PTR_ERR(mtd);
pr_err("error: cannot get MTD device\n");
return err;
}
if (mtd->writesize == 1) {
pr_info("not NAND flash, assume page size is 512 "
"bytes.\n");
pgsize = 512;
} else
pgsize = mtd->writesize;
tmp = mtd->size;
do_div(tmp, mtd->erasesize);
ebcnt = tmp;
pgcnt = mtd->erasesize / pgsize;
pr_info("MTD device size %llu, eraseblock size %u, "
"page size %u, count of eraseblocks %u, pages per "
"eraseblock %u, OOB size %u\n",
(unsigned long long)mtd->size, mtd->erasesize,
pgsize, ebcnt, pgcnt, mtd->oobsize);
if (ebcnt < 2) {
pr_err("error: need at least 2 eraseblocks\n");
err = -ENOSPC;
goto out_put_mtd;
}
/* Read or write up 2 eraseblocks at a time */
bufsize = mtd->erasesize * 2;
err = -ENOMEM;
readbuf = vmalloc(bufsize);
writebuf = vmalloc(bufsize);
offsets = kmalloc_array(ebcnt, sizeof(int), GFP_KERNEL);
if (!readbuf || !writebuf || !offsets)
goto out;
for (i = 0; i < ebcnt; i++)
offsets[i] = mtd->erasesize;
prandom_bytes(writebuf, bufsize);
bbt = kzalloc(ebcnt, GFP_KERNEL);
if (!bbt)
goto out;
err = mtdtest_scan_for_bad_eraseblocks(mtd, bbt, 0, ebcnt);
if (err)
goto out;
/* Do operations */
pr_info("doing operations\n");
for (op = 0; op < count; op++) {
if ((op & 1023) == 0)
pr_info("%d operations done\n", op);
err = do_operation();
if (err)
goto out;
err = mtdtest_relax();
if (err)
goto out;
}
pr_info("finished, %d operations done\n", op);
out:
kfree(offsets);
kfree(bbt);
vfree(writebuf);
vfree(readbuf);
out_put_mtd:
put_mtd_device(mtd);
if (err)
pr_info("error %d occurred\n", err);
printk(KERN_INFO "=================================================\n");
return err;
}
module_init(mtd_stresstest_init);
static void __exit mtd_stresstest_exit(void)
{
return;
}
module_exit(mtd_stresstest_exit);
MODULE_DESCRIPTION("Stress test module");
MODULE_AUTHOR("Adrian Hunter");
MODULE_LICENSE("GPL");
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