From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- lib/ucs2_string.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100644 lib/ucs2_string.c (limited to 'lib/ucs2_string.c') diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c new file mode 100644 index 000000000..dfb4f2358 --- /dev/null +++ b/lib/ucs2_string.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +/* Return the number of unicode characters in data */ +unsigned long +ucs2_strnlen(const ucs2_char_t *s, size_t maxlength) +{ + unsigned long length = 0; + + while (*s++ != 0 && length < maxlength) + length++; + return length; +} +EXPORT_SYMBOL(ucs2_strnlen); + +unsigned long +ucs2_strlen(const ucs2_char_t *s) +{ + return ucs2_strnlen(s, ~0UL); +} +EXPORT_SYMBOL(ucs2_strlen); + +/* + * Return the number of bytes is the length of this string + * Note: this is NOT the same as the number of unicode characters + */ +unsigned long +ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength) +{ + return ucs2_strnlen(data, maxlength/sizeof(ucs2_char_t)) * sizeof(ucs2_char_t); +} +EXPORT_SYMBOL(ucs2_strsize); + +/** + * ucs2_strscpy() - Copy a UCS2 string into a sized buffer. + * + * @dst: Pointer to the destination buffer where to copy the string to. + * @src: Pointer to the source buffer where to copy the string from. + * @count: Size of the destination buffer, in UCS2 (16-bit) characters. + * + * Like strscpy(), only for UCS2 strings. + * + * Copy the source string @src, or as much of it as fits, into the destination + * buffer @dst. The behavior is undefined if the string buffers overlap. The + * destination buffer @dst is always NUL-terminated, unless it's zero-sized. + * + * Return: The number of characters copied into @dst (excluding the trailing + * %NUL terminator) or -E2BIG if @count is 0 or @src was truncated due to the + * destination buffer being too small. + */ +ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count) +{ + long res; + + /* + * Ensure that we have a valid amount of space. We need to store at + * least one NUL-character. + */ + if (count == 0 || WARN_ON_ONCE(count > INT_MAX / sizeof(*dst))) + return -E2BIG; + + /* + * Copy at most 'count' characters, return early if we find a + * NUL-terminator. + */ + for (res = 0; res < count; res++) { + ucs2_char_t c; + + c = src[res]; + dst[res] = c; + + if (!c) + return res; + } + + /* + * The loop above terminated without finding a NUL-terminator, + * exceeding the 'count': Enforce proper NUL-termination and return + * error. + */ + dst[count - 1] = 0; + return -E2BIG; +} +EXPORT_SYMBOL(ucs2_strscpy); + +int +ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len) +{ + while (1) { + if (len == 0) + return 0; + if (*a < *b) + return -1; + if (*a > *b) + return 1; + if (*a == 0) /* implies *b == 0 */ + return 0; + a++; + b++; + len--; + } +} +EXPORT_SYMBOL(ucs2_strncmp); + +unsigned long +ucs2_utf8size(const ucs2_char_t *src) +{ + unsigned long i; + unsigned long j = 0; + + for (i = 0; src[i]; i++) { + u16 c = src[i]; + + if (c >= 0x800) + j += 3; + else if (c >= 0x80) + j += 2; + else + j += 1; + } + + return j; +} +EXPORT_SYMBOL(ucs2_utf8size); + +/* + * copy at most maxlength bytes of whole utf8 characters to dest from the + * ucs2 string src. + * + * The return value is the number of characters copied, not including the + * final NUL character. + */ +unsigned long +ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength) +{ + unsigned int i; + unsigned long j = 0; + unsigned long limit = ucs2_strnlen(src, maxlength); + + for (i = 0; maxlength && i < limit; i++) { + u16 c = src[i]; + + if (c >= 0x800) { + if (maxlength < 3) + break; + maxlength -= 3; + dest[j++] = 0xe0 | (c & 0xf000) >> 12; + dest[j++] = 0x80 | (c & 0x0fc0) >> 6; + dest[j++] = 0x80 | (c & 0x003f); + } else if (c >= 0x80) { + if (maxlength < 2) + break; + maxlength -= 2; + dest[j++] = 0xc0 | (c & 0x7c0) >> 6; + dest[j++] = 0x80 | (c & 0x03f); + } else { + maxlength -= 1; + dest[j++] = c & 0x7f; + } + } + if (maxlength) + dest[j] = '\0'; + return j; +} +EXPORT_SYMBOL(ucs2_as_utf8); + +MODULE_DESCRIPTION("UCS2 string handling"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1