bitmap_parselist has been evolved from a pretty simple idea for long and
now lacks for refactoring. It is not structured, has nested loops and a
set of opaque-named variables.
Things are more complicated than they may be because bitmap_parselist()
is a part of user interface, and its behavior should not change.
In this patchset
- __bitmap_parselist() is reworked (patches 2 and 3);
- time measurement in test_bitmap_parselist switched to ktime_get
(patch 4);
- new tests introduced (patch 5), and
- bitmap_parselist_user() testing enabled with the same testset as
bitmap_parselist() (patch 6).
Patches 1 and 4 are fixes and may be applied separately.
v1: https://lkml.org/lkml/2018/12/23/50
v2: https://www.spinics.net/lists/kernel/msg3048976.html
v2 RESEND: rebased on next-20190325 and retested.
Yury Norov (6):
bitmap_parselist: don't calculate length of the input string
bitmap_parselist: move non-parser logic to helpers
bitmap_parselist: rework input string parser
lib/test_bitmap: switch test_bitmap_parselist to ktime_get()
lib/test_bitmap: add testcases for bitmap_parselist
lib/test_bitmap: add tests for bitmap_parselist_user
lib/bitmap.c | 294 ++++++++++++++++++++++++++++++----------------
lib/test_bitmap.c | 67 +++++++++--
2 files changed, 245 insertions(+), 116 deletions(-)
--
2.17.1
The requirement for this rework is to keep the __bitmap_parselist()
copy-less and single-pass but make it more readable and maintainable by
splitting into logical parts and removing explicit nested cycles and
opaque local variables.
__bitmap_parselist() can parse userspace inputs and therefore we cannot
use simple_strtoul() to parse numbers.
Signed-off-by: Yury Norov <[email protected]>
---
lib/bitmap.c | 247 ++++++++++++++++++++++++++++++---------------------
1 file changed, 148 insertions(+), 99 deletions(-)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 307a1b20bead..aa15e529f364 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -513,6 +513,139 @@ static int bitmap_check_region(const struct region *r)
return 0;
}
+static long get_char(char *c, const char *str, int is_user)
+{
+ if (unlikely(is_user))
+ return __get_user(*c, (const char __force __user *)str);
+
+ *c = *str;
+ return 0;
+}
+
+static const char *bitmap_getnum(unsigned int *num, const char *str,
+ const char *const end, int is_user)
+{
+ unsigned int n = 0;
+ const char *_str;
+ long ret;
+ char c;
+
+ for (_str = str, *num = 0; _str <= end; _str++) {
+ ret = get_char(&c, _str, is_user);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (!isdigit(c)) {
+ if (_str == str)
+ return ERR_PTR(-EINVAL);
+
+ return _str;
+ }
+
+ *num = *num * 10 + (c - '0');
+ if (*num < n)
+ return ERR_PTR(-EOVERFLOW);
+
+ n = *num;
+ }
+
+ return _str;
+}
+
+static const char *bitmap_find_region(const char *str,
+ const char *const end, int is_user)
+{
+ long ret;
+ char c;
+
+ for (; str <= end; str++) {
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return ERR_PTR(ret);
+
+ /* Unexpected end of line. */
+ if (c == 0 || c == '\n')
+ return NULL;
+
+ /*
+ * The format allows commas and whitespases
+ * at the beginning of the region, so skip it.
+ */
+ if (!isspace(c) && c != ',')
+ break;
+ }
+
+ return str <= end ? str : NULL;
+}
+
+static const char *bitmap_parse_region(struct region *r, const char *str,
+ const char *const end, int is_user)
+{
+ long ret;
+ char c;
+
+ str = bitmap_getnum(&r->start, str, end, is_user);
+ if (IS_ERR(str))
+ return str;
+
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return (char *)ret;
+
+ if (c == 0 || c == '\n') {
+ str = end + 1;
+ goto no_end;
+ }
+
+ if (isspace(c) || c == ',')
+ goto no_end;
+
+ if (c != '-')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(&r->end, str + 1, end, is_user);
+ if (IS_ERR(str))
+ return str;
+
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return ERR_PTR(ret);
+
+ if (c == 0 || c == '\n') {
+ str = end + 1;
+ goto no_pattern;
+ }
+
+ if (isspace(c) || c == ',')
+ goto no_pattern;
+
+ if (c != ':')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(&r->off, str + 1, end, is_user);
+ if (IS_ERR(str))
+ return str;
+
+ ret = get_char(&c, str, is_user);
+ if (ret)
+ return (char *)ret;
+
+ if (c != '/')
+ return ERR_PTR(-EINVAL);
+
+ str = bitmap_getnum(&r->grlen, str + 1, end, is_user);
+
+ return str;
+
+no_end:
+ r->end = r->start;
+no_pattern:
+ r->off = r->end + 1;
+ r->grlen = r->end + 1;
+
+ return str;
+}
+
/**
* __bitmap_parselist - convert list format ASCII string to bitmap
* @buf: read nul-terminated user string from this buffer
@@ -534,113 +667,28 @@ static int bitmap_check_region(const struct region *r)
*
* Returns: 0 on success, -errno on invalid input strings. Error values:
*
- * - ``-EINVAL``: second number in range smaller than first
+ * - ``-EINVAL``: wrong region format
* - ``-EINVAL``: invalid character in string
* - ``-ERANGE``: bit number specified too large for mask
+ * - ``-EOVERFLOW``: integer overflow in the input parameters
*/
-static int __bitmap_parselist(const char *buf, unsigned int buflen,
+static int __bitmap_parselist(const char *buf, const char *const end,
int is_user, unsigned long *maskp,
int nmaskbits)
{
- unsigned int a, b, old_a, old_b;
- unsigned int group_size, used_size;
- int c, old_c, totaldigits, ndigits;
- const char __user __force *ubuf = (const char __user __force *)buf;
- int at_start, in_range, in_partial_range, ret;
struct region r;
+ long ret;
- totaldigits = c = 0;
- old_a = old_b = 0;
- group_size = used_size = 0;
bitmap_zero(maskp, nmaskbits);
- do {
- at_start = 1;
- in_range = 0;
- in_partial_range = 0;
- a = b = 0;
- ndigits = totaldigits;
-
- /* Get the next cpu# or a range of cpu#'s */
- while (buflen) {
- old_c = c;
- if (is_user) {
- if (__get_user(c, ubuf++))
- return -EFAULT;
- } else
- c = *buf++;
- buflen--;
- if (isspace(c))
- continue;
-
- /* A '\0' or a ',' signal the end of a cpu# or range */
- if (c == '\0' || c == ',')
- break;
- /*
- * whitespaces between digits are not allowed,
- * but it's ok if whitespaces are on head or tail.
- * when old_c is whilespace,
- * if totaldigits == ndigits, whitespace is on head.
- * if whitespace is on tail, it should not run here.
- * as c was ',' or '\0',
- * the last code line has broken the current loop.
- */
- if ((totaldigits != ndigits) && isspace(old_c))
- return -EINVAL;
-
- if (c == '/') {
- used_size = a;
- at_start = 1;
- in_range = 0;
- a = b = 0;
- continue;
- }
-
- if (c == ':') {
- old_a = a;
- old_b = b;
- at_start = 1;
- in_range = 0;
- in_partial_range = 1;
- a = b = 0;
- continue;
- }
-
- if (c == '-') {
- if (at_start || in_range)
- return -EINVAL;
- b = 0;
- in_range = 1;
- at_start = 1;
- continue;
- }
- if (!isdigit(c))
- return -EINVAL;
-
- b = b * 10 + (c - '0');
- if (!in_range)
- a = b;
- at_start = 0;
- totaldigits++;
- }
- if (ndigits == totaldigits)
- continue;
- if (in_partial_range) {
- group_size = a;
- a = old_a;
- b = old_b;
- old_a = old_b = 0;
- } else {
- used_size = group_size = b - a + 1;
- }
- /* if no digit is after '-', it's wrong*/
- if (at_start && in_range)
- return -EINVAL;
+ while (buf && buf <= end) {
+ buf = bitmap_find_region(buf, end, is_user);
+ if (buf == NULL)
+ return 0;
- r.start = a;
- r.off = used_size;
- r.grlen = group_size;
- r.end = b;
+ buf = bitmap_parse_region(&r, buf, end, is_user);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
ret = bitmap_check_region(&r);
if (ret)
@@ -649,14 +697,14 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
ret = bitmap_set_region(&r, maskp, nmaskbits);
if (ret)
return ret;
+ }
- } while (buflen && c == ',');
return 0;
}
int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
{
- return __bitmap_parselist(bp, UINT_MAX, 0, maskp, nmaskbits);
+ return __bitmap_parselist(bp, (char *)SIZE_MAX, 0, maskp, nmaskbits);
}
EXPORT_SYMBOL(bitmap_parselist);
@@ -683,7 +731,8 @@ int bitmap_parselist_user(const char __user *ubuf,
if (!access_ok(ubuf, ulen))
return -EFAULT;
return __bitmap_parselist((const char __force *)ubuf,
- ulen, 1, maskp, nmaskbits);
+ (const char __force *)ubuf + ulen - 1,
+ 1, maskp, nmaskbits);
}
EXPORT_SYMBOL(bitmap_parselist_user);
--
2.17.1
Propagate existing bitmap_parselist() tests to bitmap_parselist_user().
Signed-off-by: Yury Norov <[email protected]>
---
lib/test_bitmap.c | 46 ++++++++++++++++++++++++++++++++++++----------
1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 709424a788ee..d4ecac0da160 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -11,6 +11,7 @@
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/string.h>
+#include <linux/uaccess.h>
static unsigned total_tests __initdata;
static unsigned failed_tests __initdata;
@@ -278,39 +279,63 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
{-EINVAL, "0-\n", NULL, 8, 0},
};
-static void __init test_bitmap_parselist(void)
+static void __init __test_bitmap_parselist(int is_user)
{
int i;
int err;
ktime_t time;
DECLARE_BITMAP(bmap, 2048);
+ char *mode = is_user ? "_user" : "";
for (i = 0; i < ARRAY_SIZE(parselist_tests); i++) {
#define ptest parselist_tests[i]
- time = ktime_get();
- err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
- time = ktime_get() - time;
+ if (is_user) {
+ mm_segment_t orig_fs = get_fs();
+ size_t len = strlen(ptest.in);
+
+ set_fs(KERNEL_DS);
+ time = ktime_get();
+ err = bitmap_parselist_user(ptest.in, len,
+ bmap, ptest.nbits);
+ time = ktime_get() - time;
+ set_fs(orig_fs);
+ } else {
+ time = ktime_get();
+ err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
+ time = ktime_get() - time;
+ }
if (err != ptest.errno) {
- pr_err("test %d: input is %s, errno is %d, expected %d\n",
- i, ptest.in, err, ptest.errno);
+ pr_err("parselist%s: %d: input is %s, errno is %d, expected %d\n",
+ mode, i, ptest.in, err, ptest.errno);
continue;
}
if (!err && ptest.expected
&& !__bitmap_equal(bmap, ptest.expected, ptest.nbits)) {
- pr_err("test %d: input is %s, result is 0x%lx, expected 0x%lx\n",
- i, ptest.in, bmap[0], *ptest.expected);
+ pr_err("parselist%s: %d: input is %s, result is 0x%lx, expected 0x%lx\n",
+ mode, i, ptest.in, bmap[0],
+ *ptest.expected);
continue;
}
if (ptest.flags & PARSE_TIME)
- pr_err("test %d: input is '%s' OK, Time: %llu\n",
- i, ptest.in, time);
+ pr_err("parselist%s: %d: input is '%s' OK, Time: %llu\n",
+ mode, i, ptest.in, time);
}
}
+static void __init test_bitmap_parselist(void)
+{
+ __test_bitmap_parselist(0);
+}
+
+static void __init test_bitmap_parselist_user(void)
+{
+ __test_bitmap_parselist(1);
+}
+
#define EXP_BYTES (sizeof(exp) * 8)
static void __init test_bitmap_arr32(void)
@@ -383,6 +408,7 @@ static int __init test_bitmap_init(void)
test_copy();
test_bitmap_arr32();
test_bitmap_parselist();
+ test_bitmap_parselist_user();
test_mem_optimisations();
if (failed_tests == 0)
--
2.17.1
test_bitmap_parselist uses get_cycles(). Only arm, arm64, openrisc,
riscv and sparc64 implement get_cycles() and others take a stub from
include/asm-generic/timex.h.
So, switch to more generic ktime_get().
Fixes: 6df0d464dbcc1a55 (lib/test_bitmap.c: add test for bitmap_parselist())
Signed-off-by: Yury Norov <[email protected]>
---
lib/test_bitmap.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 6cd7d0740005..b06e0fd3811b 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -266,15 +266,15 @@ static void __init test_bitmap_parselist(void)
{
int i;
int err;
- cycles_t cycles;
+ ktime_t time;
DECLARE_BITMAP(bmap, 2048);
for (i = 0; i < ARRAY_SIZE(parselist_tests); i++) {
#define ptest parselist_tests[i]
- cycles = get_cycles();
+ time = ktime_get();
err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
- cycles = get_cycles() - cycles;
+ time = ktime_get() - time;
if (err != ptest.errno) {
pr_err("test %d: input is %s, errno is %d, expected %d\n",
@@ -291,8 +291,7 @@ static void __init test_bitmap_parselist(void)
if (ptest.flags & PARSE_TIME)
pr_err("test %d: input is '%s' OK, Time: %llu\n",
- i, ptest.in,
- (unsigned long long)cycles);
+ i, ptest.in, time);
}
}
--
2.17.1
bitmap_parselist() calculates length of the input string before passing
it to the __bitmap_parselist(). But the end-of-line condition is checked
for every character in __bitmap_parselist() anyway. So doing it in wrapper
is a simple waste of time.
Signed-off-by: Yury Norov <[email protected]>
---
lib/bitmap.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 98872e9025da..ad1fb7e6ad0e 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -614,10 +614,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
{
- char *nl = strchrnul(bp, '\n');
- int len = nl - bp;
-
- return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
+ return __bitmap_parselist(bp, UINT_MAX, 0, maskp, nmaskbits);
}
EXPORT_SYMBOL(bitmap_parselist);
--
2.17.1
Add tests for non-number character, empty regions, integer overflow.
Signed-off-by: Yury Norov <[email protected]>
---
lib/test_bitmap.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index b06e0fd3811b..709424a788ee 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -224,7 +224,8 @@ static const unsigned long exp[] __initconst = {
BITMAP_FROM_U64(0xffffffff),
BITMAP_FROM_U64(0xfffffffe),
BITMAP_FROM_U64(0x3333333311111111ULL),
- BITMAP_FROM_U64(0xffffffff77777777ULL)
+ BITMAP_FROM_U64(0xffffffff77777777ULL),
+ BITMAP_FROM_U64(0),
};
static const unsigned long exp2[] __initconst = {
@@ -247,19 +248,34 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
{0, "1-31:4/4", &exp[9 * step], 32, 0},
{0, "0-31:1/4,32-63:2/4", &exp[10 * step], 64, 0},
{0, "0-31:3/4,32-63:4/4", &exp[11 * step], 64, 0},
+ {0, " ,, 0-31:3/4 ,, 32-63:4/4 ,, ", &exp[11 * step], 64, 0},
{0, "0-31:1/4,32-63:2/4,64-95:3/4,96-127:4/4", exp2, 128, 0},
{0, "0-2047:128/256", NULL, 2048, PARSE_TIME},
+ {0, "", &exp[12], 8, 0},
+ {0, "\n", &exp[12], 8, 0},
+ {0, ",, ,, , , ,", &exp[12], 8, 0},
+ {0, " , ,, , , ", &exp[12], 8, 0},
+ {0, " , ,, , , \n", &exp[12], 8, 0},
+
{-EINVAL, "-1", NULL, 8, 0},
{-EINVAL, "-0", NULL, 8, 0},
{-EINVAL, "10-1", NULL, 8, 0},
{-EINVAL, "0-31:", NULL, 8, 0},
{-EINVAL, "0-31:0", NULL, 8, 0},
+ {-EINVAL, "0-31:0/", NULL, 8, 0},
{-EINVAL, "0-31:0/0", NULL, 8, 0},
{-EINVAL, "0-31:1/0", NULL, 8, 0},
{-EINVAL, "0-31:10/1", NULL, 8, 0},
+ {-EOVERFLOW, "0-98765432123456789:10/1", NULL, 8, 0},
+
+ {-EINVAL, "a-31", NULL, 8, 0},
+ {-EINVAL, "0-a1", NULL, 8, 0},
+ {-EINVAL, "a-31:10/1", NULL, 8, 0},
+ {-EINVAL, "0-31:a/1", NULL, 8, 0},
+ {-EINVAL, "0-\n", NULL, 8, 0},
};
static void __init test_bitmap_parselist(void)
--
2.17.1
Move region checking and setting functionality of __bitmap_parselist()
to helpers.
Signed-off-by: Yury Norov <[email protected]>
---
lib/bitmap.c | 64 +++++++++++++++++++++++++++++++++++++++++++---------
1 file changed, 53 insertions(+), 11 deletions(-)
diff --git a/lib/bitmap.c b/lib/bitmap.c
index ad1fb7e6ad0e..307a1b20bead 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -477,6 +477,42 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
}
EXPORT_SYMBOL(bitmap_print_to_pagebuf);
+/*
+ * Region 9-38:4/10 describes the following bitmap structure:
+ * 0 9 12 18 38
+ * .........****......****......****......
+ * ^ ^ ^ ^
+ * start off grlen end
+ */
+struct region {
+ unsigned int start;
+ unsigned int off;
+ unsigned int grlen;
+ unsigned int end;
+};
+
+static int bitmap_set_region(const struct region *r,
+ unsigned long *bitmap, int nbits)
+{
+ unsigned int start;
+
+ if (r->end >= nbits)
+ return -ERANGE;
+
+ for (start = r->start; start <= r->end; start += r->grlen)
+ bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
+
+ return 0;
+}
+
+static int bitmap_check_region(const struct region *r)
+{
+ if (r->start > r->end || r->grlen == 0 || r->off > r->grlen)
+ return -EINVAL;
+
+ return 0;
+}
+
/**
* __bitmap_parselist - convert list format ASCII string to bitmap
* @buf: read nul-terminated user string from this buffer
@@ -507,10 +543,11 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
int nmaskbits)
{
unsigned int a, b, old_a, old_b;
- unsigned int group_size, used_size, off;
+ unsigned int group_size, used_size;
int c, old_c, totaldigits, ndigits;
const char __user __force *ubuf = (const char __user __force *)buf;
- int at_start, in_range, in_partial_range;
+ int at_start, in_range, in_partial_range, ret;
+ struct region r;
totaldigits = c = 0;
old_a = old_b = 0;
@@ -599,15 +636,20 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
/* if no digit is after '-', it's wrong*/
if (at_start && in_range)
return -EINVAL;
- if (!(a <= b) || group_size == 0 || !(used_size <= group_size))
- return -EINVAL;
- if (b >= nmaskbits)
- return -ERANGE;
- while (a <= b) {
- off = min(b - a + 1, used_size);
- bitmap_set(maskp, a, off);
- a += group_size;
- }
+
+ r.start = a;
+ r.off = used_size;
+ r.grlen = group_size;
+ r.end = b;
+
+ ret = bitmap_check_region(&r);
+ if (ret)
+ return ret;
+
+ ret = bitmap_set_region(&r, maskp, nmaskbits);
+ if (ret)
+ return ret;
+
} while (buflen && c == ',');
return 0;
}
--
2.17.1
On Tue, 26 Mar 2019 00:07:44 +0300 Yury Norov <[email protected]> wrote:
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -477,6 +477,42 @@ int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
> }
> EXPORT_SYMBOL(bitmap_print_to_pagebuf);
>
> +/*
> + * Region 9-38:4/10 describes the following bitmap structure:
> + * 0 9 12 18 38
> + * .........****......****......****......
> + * ^ ^ ^ ^
> + * start off grlen end
> + */
> +struct region {
> + unsigned int start;
> + unsigned int off;
> + unsigned int grlen;
> + unsigned int end;
> +};
grlen means... group_len, I think?
Perhaps it should be called group_len ;)
On Tue, Mar 26, 2019 at 12:07:43AM +0300, Yury Norov wrote:
> bitmap_parselist() calculates length of the input string before passing
> it to the __bitmap_parselist(). But the end-of-line condition is checked
> for every character in __bitmap_parselist() anyway. So doing it in wrapper
> is a simple waste of time.
This is not best change, I think. See my further comments.
>
> Signed-off-by: Yury Norov <[email protected]>
> ---
> lib/bitmap.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/lib/bitmap.c b/lib/bitmap.c
> index 98872e9025da..ad1fb7e6ad0e 100644
> --- a/lib/bitmap.c
> +++ b/lib/bitmap.c
> @@ -614,10 +614,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen,
>
> int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
> {
> - char *nl = strchrnul(bp, '\n');
> - int len = nl - bp;
> -
> - return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
> + return __bitmap_parselist(bp, UINT_MAX, 0, maskp, nmaskbits);
> }
> EXPORT_SYMBOL(bitmap_parselist);
>
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
On Tue, Mar 26, 2019 at 12:07:45AM +0300, Yury Norov wrote:
> The requirement for this rework is to keep the __bitmap_parselist()
> copy-less and single-pass but make it more readable and maintainable by
> splitting into logical parts and removing explicit nested cycles and
> opaque local variables.
>
> __bitmap_parselist() can parse userspace inputs and therefore we cannot
> use simple_strtoul() to parse numbers.
> +static long get_char(char *c, const char *str, int is_user)
> +{
> + if (unlikely(is_user))
Can is_user be boolean?
Can we name it from_user or is_from_user?
> + return __get_user(*c, (const char __force __user *)str);
> +
> + *c = *str;
> + return 0;
> +}
> +
> +static const char *bitmap_getnum(unsigned int *num, const char *str,
> + const char *const end, int is_user)
> +{
> + unsigned int n = 0;
> + const char *_str;
> + long ret;
> + char c;
> +
> + for (_str = str, *num = 0; _str <= end; _str++) {
> + ret = get_char(&c, _str, is_user);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + if (!isdigit(c)) {
> + if (_str == str)
> + return ERR_PTR(-EINVAL);
> +
> + return _str;
> + }
> +
> + *num = *num * 10 + (c - '0');
> + if (*num < n)
> + return ERR_PTR(-EOVERFLOW);
> +
> + n = *num;
> + }
Can't we do other way around, i.e. move the loop body to a helper and do
something like this:
if (is_from_user) {
for (...) {
__get_user(...);
helper1();
helper2();
}
} else {
for (...) {
*c = *str;
helper1();
helper2()
}
}
Each branch can be optimized more I think.
> +
> + return _str;
> +}
> +
> +static const char *bitmap_find_region(const char *str,
> + const char *const end, int is_user)
> +{
> + long ret;
> + char c;
> +
> + for (; str <= end; str++) {
> + ret = get_char(&c, str, is_user);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + /* Unexpected end of line. */
> + if (c == 0 || c == '\n')
> + return NULL;
> +
> + /*
> + * The format allows commas and whitespases
> + * at the beginning of the region, so skip it.
> + */
> + if (!isspace(c) && c != ',')
> + break;
> + }
> +
> + return str <= end ? str : NULL;
> +}
> +
> +static const char *bitmap_parse_region(struct region *r, const char *str,
> + const char *const end, int is_user)
> +{
> + long ret;
> + char c;
> +
> + str = bitmap_getnum(&r->start, str, end, is_user);
> + if (IS_ERR(str))
> + return str;
> +
> + ret = get_char(&c, str, is_user);
> + if (ret)
> + return (char *)ret;
> +
> + if (c == 0 || c == '\n') {
> + str = end + 1;
> + goto no_end;
> + }
> +
> + if (isspace(c) || c == ',')
> + goto no_end;
> +
> + if (c != '-')
> + return ERR_PTR(-EINVAL);
> +
> + str = bitmap_getnum(&r->end, str + 1, end, is_user);
> + if (IS_ERR(str))
> + return str;
> +
> + ret = get_char(&c, str, is_user);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + if (c == 0 || c == '\n') {
> + str = end + 1;
> + goto no_pattern;
> + }
> +
> + if (isspace(c) || c == ',')
> + goto no_pattern;
> +
> + if (c != ':')
> + return ERR_PTR(-EINVAL);
> +
> + str = bitmap_getnum(&r->off, str + 1, end, is_user);
> + if (IS_ERR(str))
> + return str;
> +
> + ret = get_char(&c, str, is_user);
> + if (ret)
> + return (char *)ret;
> +
> + if (c != '/')
> + return ERR_PTR(-EINVAL);
> +
> + str = bitmap_getnum(&r->grlen, str + 1, end, is_user);
> +
> + return str;
return bitmap_getnum(...);
> +
> +no_end:
> + r->end = r->start;
> +no_pattern:
> + r->off = r->end + 1;
> + r->grlen = r->end + 1;
> +
> + return str;
> +}
> +
So, all above depends to what memory we access kernel / user space.
Perhaps we can get copy of memory of a given size and then parse it in kernel space always?
--
With Best Regards,
Andy Shevchenko
On Tue, Mar 26, 2019 at 12:07:48AM +0300, Yury Norov wrote:
> Propagate existing bitmap_parselist() tests to bitmap_parselist_user().
Increasing test coverage is a good point,
Reviewed-by: Andy Shevchenko <[email protected]>
for all test related patches
>
> Signed-off-by: Yury Norov <[email protected]>
> ---
> lib/test_bitmap.c | 46 ++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 36 insertions(+), 10 deletions(-)
>
> diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
> index 709424a788ee..d4ecac0da160 100644
> --- a/lib/test_bitmap.c
> +++ b/lib/test_bitmap.c
> @@ -11,6 +11,7 @@
> #include <linux/printk.h>
> #include <linux/slab.h>
> #include <linux/string.h>
> +#include <linux/uaccess.h>
>
> static unsigned total_tests __initdata;
> static unsigned failed_tests __initdata;
> @@ -278,39 +279,63 @@ static const struct test_bitmap_parselist parselist_tests[] __initconst = {
> {-EINVAL, "0-\n", NULL, 8, 0},
> };
>
> -static void __init test_bitmap_parselist(void)
> +static void __init __test_bitmap_parselist(int is_user)
> {
> int i;
> int err;
> ktime_t time;
> DECLARE_BITMAP(bmap, 2048);
> + char *mode = is_user ? "_user" : "";
>
> for (i = 0; i < ARRAY_SIZE(parselist_tests); i++) {
> #define ptest parselist_tests[i]
>
> - time = ktime_get();
> - err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
> - time = ktime_get() - time;
> + if (is_user) {
> + mm_segment_t orig_fs = get_fs();
> + size_t len = strlen(ptest.in);
> +
> + set_fs(KERNEL_DS);
> + time = ktime_get();
> + err = bitmap_parselist_user(ptest.in, len,
> + bmap, ptest.nbits);
> + time = ktime_get() - time;
> + set_fs(orig_fs);
> + } else {
> + time = ktime_get();
> + err = bitmap_parselist(ptest.in, bmap, ptest.nbits);
> + time = ktime_get() - time;
> + }
>
> if (err != ptest.errno) {
> - pr_err("test %d: input is %s, errno is %d, expected %d\n",
> - i, ptest.in, err, ptest.errno);
> + pr_err("parselist%s: %d: input is %s, errno is %d, expected %d\n",
> + mode, i, ptest.in, err, ptest.errno);
> continue;
> }
>
> if (!err && ptest.expected
> && !__bitmap_equal(bmap, ptest.expected, ptest.nbits)) {
> - pr_err("test %d: input is %s, result is 0x%lx, expected 0x%lx\n",
> - i, ptest.in, bmap[0], *ptest.expected);
> + pr_err("parselist%s: %d: input is %s, result is 0x%lx, expected 0x%lx\n",
> + mode, i, ptest.in, bmap[0],
> + *ptest.expected);
> continue;
> }
>
> if (ptest.flags & PARSE_TIME)
> - pr_err("test %d: input is '%s' OK, Time: %llu\n",
> - i, ptest.in, time);
> + pr_err("parselist%s: %d: input is '%s' OK, Time: %llu\n",
> + mode, i, ptest.in, time);
> }
> }
>
> +static void __init test_bitmap_parselist(void)
> +{
> + __test_bitmap_parselist(0);
> +}
> +
> +static void __init test_bitmap_parselist_user(void)
> +{
> + __test_bitmap_parselist(1);
> +}
> +
> #define EXP_BYTES (sizeof(exp) * 8)
>
> static void __init test_bitmap_arr32(void)
> @@ -383,6 +408,7 @@ static int __init test_bitmap_init(void)
> test_copy();
> test_bitmap_arr32();
> test_bitmap_parselist();
> + test_bitmap_parselist_user();
> test_mem_optimisations();
>
> if (failed_tests == 0)
> --
> 2.17.1
>
--
With Best Regards,
Andy Shevchenko
+ Mike Travis <[email protected]>
+ Thomas Gleixner <[email protected]>
----------------------------------------------------------------------
On Tue, Mar 26, 2019 at 12:07:45AM +0300, Yury Norov wrote:
>> The requirement for this rework is to keep the __bitmap_parselist()
>> copy-less and single-pass but make it more readable and maintainable by
>> splitting into logical parts and removing explicit nested cycles and
>> opaque local variables.
>>
>> __bitmap_parselist() can parse userspace inputs and therefore we cannot
>> use simple_strtoul() to parse numbers.
> So, all above depends to what memory we access kernel / user space.
> Perhaps we can get copy of memory of a given size and then parse it in kernel space always?
> --
> With Best Regards,
> Andy Shevchenko
What I missed during rework is that we have only one caller of *parselist_user? -
it's write_irq_affinity() introduced by Mike Travis in kernel/irq/proc.c. It doesn't look
like a hot path as it's file operations handler. If no objections from Mike or Thomas,
I think it would make sense to copy_from_user() the userspace data at the beginning
in sake of simplicity of __bitmap_parselist(), as you suggested above.
Yury
On 3/26/2019 2:09 PM, Yuri Norov wrote:
> + Mike Travis <[email protected]>
> + Thomas Gleixner <[email protected]>
>
> ----------------------------------------------------------------------
> On Tue, Mar 26, 2019 at 12:07:45AM +0300, Yury Norov wrote:
>>> The requirement for this rework is to keep the __bitmap_parselist()
>>> copy-less and single-pass but make it more readable and maintainable by
>>> splitting into logical parts and removing explicit nested cycles and
>>> opaque local variables.
>>>
>>> __bitmap_parselist() can parse userspace inputs and therefore we cannot
>>> use simple_strtoul() to parse numbers.
>
>> So, all above depends to what memory we access kernel / user space.
>> Perhaps we can get copy of memory of a given size and then parse it in kernel space always?
>
>> --
>> With Best Regards,
>> Andy Shevchenko
>
> What I missed during rework is that we have only one caller of *parselist_user? -
> it's write_irq_affinity() introduced by Mike Travis in kernel/irq/proc.c. It doesn't look
> like a hot path as it's file operations handler. If no objections from Mike or Thomas,
No objections from me as long as you can still change irq affinity using
a cpulist instead of a cpumask.
Thanks,
Mike Travis
> I think it would make sense to copy_from_user() the userspace data at the beginning
> in sake of simplicity of __bitmap_parselist(), as you suggested above.
>
> Yury
>