From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- lib/textsearch.c | 323 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 323 insertions(+) create mode 100644 lib/textsearch.c (limited to 'lib/textsearch.c') diff --git a/lib/textsearch.c b/lib/textsearch.c new file mode 100644 index 000000000..f68dea880 --- /dev/null +++ b/lib/textsearch.c @@ -0,0 +1,323 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * lib/textsearch.c Generic text search interface + * + * Authors: Thomas Graf + * Pablo Neira Ayuso + * + * ========================================================================== + */ + +/** + * DOC: ts_intro + * INTRODUCTION + * + * The textsearch infrastructure provides text searching facilities for + * both linear and non-linear data. Individual search algorithms are + * implemented in modules and chosen by the user. + * + * ARCHITECTURE + * + * .. code-block:: none + * + * User + * +----------------+ + * | finish()|<--------------(6)-----------------+ + * |get_next_block()|<--------------(5)---------------+ | + * | | Algorithm | | + * | | +------------------------------+ + * | | | init() find() destroy() | + * | | +------------------------------+ + * | | Core API ^ ^ ^ + * | | +---------------+ (2) (4) (8) + * | (1)|----->| prepare() |---+ | | + * | (3)|----->| find()/next() |-----------+ | + * | (7)|----->| destroy() |----------------------+ + * +----------------+ +---------------+ + * + * (1) User configures a search by calling textsearch_prepare() specifying + * the search parameters such as the pattern and algorithm name. + * (2) Core requests the algorithm to allocate and initialize a search + * configuration according to the specified parameters. + * (3) User starts the search(es) by calling textsearch_find() or + * textsearch_next() to fetch subsequent occurrences. A state variable + * is provided to the algorithm to store persistent variables. + * (4) Core eventually resets the search offset and forwards the find() + * request to the algorithm. + * (5) Algorithm calls get_next_block() provided by the user continuously + * to fetch the data to be searched in block by block. + * (6) Algorithm invokes finish() after the last call to get_next_block + * to clean up any leftovers from get_next_block. (Optional) + * (7) User destroys the configuration by calling textsearch_destroy(). + * (8) Core notifies the algorithm to destroy algorithm specific + * allocations. (Optional) + * + * USAGE + * + * Before a search can be performed, a configuration must be created + * by calling textsearch_prepare() specifying the searching algorithm, + * the pattern to look for and flags. As a flag, you can set TS_IGNORECASE + * to perform case insensitive matching. But it might slow down + * performance of algorithm, so you should use it at own your risk. + * The returned configuration may then be used for an arbitrary + * amount of times and even in parallel as long as a separate struct + * ts_state variable is provided to every instance. + * + * The actual search is performed by either calling + * textsearch_find_continuous() for linear data or by providing + * an own get_next_block() implementation and + * calling textsearch_find(). Both functions return + * the position of the first occurrence of the pattern or UINT_MAX if + * no match was found. Subsequent occurrences can be found by calling + * textsearch_next() regardless of the linearity of the data. + * + * Once you're done using a configuration it must be given back via + * textsearch_destroy. + * + * EXAMPLE:: + * + * int pos; + * struct ts_config *conf; + * struct ts_state state; + * const char *pattern = "chicken"; + * const char *example = "We dance the funky chicken"; + * + * conf = textsearch_prepare("kmp", pattern, strlen(pattern), + * GFP_KERNEL, TS_AUTOLOAD); + * if (IS_ERR(conf)) { + * err = PTR_ERR(conf); + * goto errout; + * } + * + * pos = textsearch_find_continuous(conf, &state, example, strlen(example)); + * if (pos != UINT_MAX) + * panic("Oh my god, dancing chickens at %d\n", pos); + * + * textsearch_destroy(conf); + */ +/* ========================================================================== */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static LIST_HEAD(ts_ops); +static DEFINE_SPINLOCK(ts_mod_lock); + +static inline struct ts_ops *lookup_ts_algo(const char *name) +{ + struct ts_ops *o; + + rcu_read_lock(); + list_for_each_entry_rcu(o, &ts_ops, list) { + if (!strcmp(name, o->name)) { + if (!try_module_get(o->owner)) + o = NULL; + rcu_read_unlock(); + return o; + } + } + rcu_read_unlock(); + + return NULL; +} + +/** + * textsearch_register - register a textsearch module + * @ops: operations lookup table + * + * This function must be called by textsearch modules to announce + * their presence. The specified &@ops must have %name set to a + * unique identifier and the callbacks find(), init(), get_pattern(), + * and get_pattern_len() must be implemented. + * + * Returns 0 or -EEXISTS if another module has already registered + * with same name. + */ +int textsearch_register(struct ts_ops *ops) +{ + int err = -EEXIST; + struct ts_ops *o; + + if (ops->name == NULL || ops->find == NULL || ops->init == NULL || + ops->get_pattern == NULL || ops->get_pattern_len == NULL) + return -EINVAL; + + spin_lock(&ts_mod_lock); + list_for_each_entry(o, &ts_ops, list) { + if (!strcmp(ops->name, o->name)) + goto errout; + } + + list_add_tail_rcu(&ops->list, &ts_ops); + err = 0; +errout: + spin_unlock(&ts_mod_lock); + return err; +} +EXPORT_SYMBOL(textsearch_register); + +/** + * textsearch_unregister - unregister a textsearch module + * @ops: operations lookup table + * + * This function must be called by textsearch modules to announce + * their disappearance for examples when the module gets unloaded. + * The &ops parameter must be the same as the one during the + * registration. + * + * Returns 0 on success or -ENOENT if no matching textsearch + * registration was found. + */ +int textsearch_unregister(struct ts_ops *ops) +{ + int err = 0; + struct ts_ops *o; + + spin_lock(&ts_mod_lock); + list_for_each_entry(o, &ts_ops, list) { + if (o == ops) { + list_del_rcu(&o->list); + goto out; + } + } + + err = -ENOENT; +out: + spin_unlock(&ts_mod_lock); + return err; +} +EXPORT_SYMBOL(textsearch_unregister); + +struct ts_linear_state +{ + unsigned int len; + const void *data; +}; + +static unsigned int get_linear_data(unsigned int consumed, const u8 **dst, + struct ts_config *conf, + struct ts_state *state) +{ + struct ts_linear_state *st = (struct ts_linear_state *) state->cb; + + if (likely(consumed < st->len)) { + *dst = st->data + consumed; + return st->len - consumed; + } + + return 0; +} + +/** + * textsearch_find_continuous - search a pattern in continuous/linear data + * @conf: search configuration + * @state: search state + * @data: data to search in + * @len: length of data + * + * A simplified version of textsearch_find() for continuous/linear data. + * Call textsearch_next() to retrieve subsequent matches. + * + * Returns the position of first occurrence of the pattern or + * %UINT_MAX if no occurrence was found. + */ +unsigned int textsearch_find_continuous(struct ts_config *conf, + struct ts_state *state, + const void *data, unsigned int len) +{ + struct ts_linear_state *st = (struct ts_linear_state *) state->cb; + + conf->get_next_block = get_linear_data; + st->data = data; + st->len = len; + + return textsearch_find(conf, state); +} +EXPORT_SYMBOL(textsearch_find_continuous); + +/** + * textsearch_prepare - Prepare a search + * @algo: name of search algorithm + * @pattern: pattern data + * @len: length of pattern + * @gfp_mask: allocation mask + * @flags: search flags + * + * Looks up the search algorithm module and creates a new textsearch + * configuration for the specified pattern. + * + * Note: The format of the pattern may not be compatible between + * the various search algorithms. + * + * Returns a new textsearch configuration according to the specified + * parameters or a ERR_PTR(). If a zero length pattern is passed, this + * function returns EINVAL. + */ +struct ts_config *textsearch_prepare(const char *algo, const void *pattern, + unsigned int len, gfp_t gfp_mask, int flags) +{ + int err = -ENOENT; + struct ts_config *conf; + struct ts_ops *ops; + + if (len == 0) + return ERR_PTR(-EINVAL); + + ops = lookup_ts_algo(algo); +#ifdef CONFIG_MODULES + /* + * Why not always autoload you may ask. Some users are + * in a situation where requesting a module may deadlock, + * especially when the module is located on a NFS mount. + */ + if (ops == NULL && flags & TS_AUTOLOAD) { + request_module("ts_%s", algo); + ops = lookup_ts_algo(algo); + } +#endif + + if (ops == NULL) + goto errout; + + conf = ops->init(pattern, len, gfp_mask, flags); + if (IS_ERR(conf)) { + err = PTR_ERR(conf); + goto errout; + } + + conf->ops = ops; + return conf; + +errout: + if (ops) + module_put(ops->owner); + + return ERR_PTR(err); +} +EXPORT_SYMBOL(textsearch_prepare); + +/** + * textsearch_destroy - destroy a search configuration + * @conf: search configuration + * + * Releases all references of the configuration and frees + * up the memory. + */ +void textsearch_destroy(struct ts_config *conf) +{ + if (conf->ops) { + if (conf->ops->destroy) + conf->ops->destroy(conf); + module_put(conf->ops->owner); + } + + kfree(conf); +} +EXPORT_SYMBOL(textsearch_destroy); -- cgit v1.3.1