From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- drivers/mtd/chips/chipreg.c | 102 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 drivers/mtd/chips/chipreg.c (limited to 'drivers/mtd/chips/chipreg.c') diff --git a/drivers/mtd/chips/chipreg.c b/drivers/mtd/chips/chipreg.c new file mode 100644 index 000000000..a05e10368 --- /dev/null +++ b/drivers/mtd/chips/chipreg.c @@ -0,0 +1,102 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Registration for chip drivers + * + */ + +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_SPINLOCK(chip_drvs_lock); +static LIST_HEAD(chip_drvs_list); + +void register_mtd_chip_driver(struct mtd_chip_driver *drv) +{ + spin_lock(&chip_drvs_lock); + list_add(&drv->list, &chip_drvs_list); + spin_unlock(&chip_drvs_lock); +} + +void unregister_mtd_chip_driver(struct mtd_chip_driver *drv) +{ + spin_lock(&chip_drvs_lock); + list_del(&drv->list); + spin_unlock(&chip_drvs_lock); +} + +static struct mtd_chip_driver *get_mtd_chip_driver (const char *name) +{ + struct mtd_chip_driver *ret = NULL, *this; + + spin_lock(&chip_drvs_lock); + + list_for_each_entry(this, &chip_drvs_list, list) { + if (!strcmp(this->name, name)) { + ret = this; + break; + } + } + if (ret && !try_module_get(ret->module)) + ret = NULL; + + spin_unlock(&chip_drvs_lock); + + return ret; +} + + /* Hide all the horrid details, like some silly person taking + get_module_symbol() away from us, from the caller. */ + +struct mtd_info *do_map_probe(const char *name, struct map_info *map) +{ + struct mtd_chip_driver *drv; + struct mtd_info *ret; + + drv = get_mtd_chip_driver(name); + + if (!drv && !request_module("%s", name)) + drv = get_mtd_chip_driver(name); + + if (!drv) + return NULL; + + ret = drv->probe(map); + + /* We decrease the use count here. It may have been a + probe-only module, which is no longer required from this + point, having given us a handle on (and increased the use + count of) the actual driver code. + */ + module_put(drv->module); + + return ret; +} +/* + * Destroy an MTD device which was created for a map device. + * Make sure the MTD device is already unregistered before calling this + */ +void map_destroy(struct mtd_info *mtd) +{ + struct map_info *map = mtd->priv; + + if (map->fldrv->destroy) + map->fldrv->destroy(mtd); + + module_put(map->fldrv->module); + + kfree(mtd); +} + +EXPORT_SYMBOL(register_mtd_chip_driver); +EXPORT_SYMBOL(unregister_mtd_chip_driver); +EXPORT_SYMBOL(do_map_probe); +EXPORT_SYMBOL(map_destroy); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("David Woodhouse "); +MODULE_DESCRIPTION("Core routines for registering and invoking MTD chip drivers"); -- cgit v1.3.1