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/dio/dio-driver.c | 142 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 drivers/dio/dio-driver.c (limited to 'drivers/dio/dio-driver.c') diff --git a/drivers/dio/dio-driver.c b/drivers/dio/dio-driver.c new file mode 100644 index 000000000..12fa2d209 --- /dev/null +++ b/drivers/dio/dio-driver.c @@ -0,0 +1,142 @@ +/* + * DIO Driver Services + * + * Copyright (C) 2004 Jochen Friedrich + * + * Loosely based on drivers/pci/pci-driver.c and drivers/zorro/zorro-driver.c + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ + +#include +#include +#include + + +/** + * dio_match_device - Tell if a DIO device structure has a matching DIO device id structure + * @ids: array of DIO device id structures to search in + * @d: the DIO device structure to match against + * + * Used by a driver to check whether a DIO device present in the + * system is in its list of supported devices. Returns the matching + * dio_device_id structure or %NULL if there is no match. + */ + +static const struct dio_device_id * +dio_match_device(const struct dio_device_id *ids, + const struct dio_dev *d) +{ + while (ids->id) { + if (ids->id == DIO_WILDCARD) + return ids; + if (DIO_NEEDSSECID(ids->id & 0xff)) { + if (ids->id == d->id) + return ids; + } else { + if ((ids->id & 0xff) == (d->id & 0xff)) + return ids; + } + ids++; + } + return NULL; +} + +static int dio_device_probe(struct device *dev) +{ + int error = 0; + struct dio_driver *drv = to_dio_driver(dev->driver); + struct dio_dev *d = to_dio_dev(dev); + + if (!d->driver && drv->probe) { + const struct dio_device_id *id; + + id = dio_match_device(drv->id_table, d); + if (id) + error = drv->probe(d, id); + if (error >= 0) { + d->driver = drv; + error = 0; + } + } + return error; +} + + +/** + * dio_register_driver - register a new DIO driver + * @drv: the driver structure to register + * + * Adds the driver structure to the list of registered drivers + * Returns zero or a negative error value. + */ + +int dio_register_driver(struct dio_driver *drv) +{ + /* initialize common driver fields */ + drv->driver.name = drv->name; + drv->driver.bus = &dio_bus_type; + + /* register with core */ + return driver_register(&drv->driver); +} + + +/** + * dio_unregister_driver - unregister a DIO driver + * @drv: the driver structure to unregister + * + * Deletes the driver structure from the list of registered DIO drivers, + * gives it a chance to clean up by calling its remove() function for + * each device it was responsible for, and marks those devices as + * driverless. + */ + +void dio_unregister_driver(struct dio_driver *drv) +{ + driver_unregister(&drv->driver); +} + + +/** + * dio_bus_match - Tell if a DIO device structure has a matching DIO device id structure + * @dev: the DIO device structure to match against + * @drv: the &device_driver that points to the array of DIO device id structures to search + * + * Used by the driver core to check whether a DIO device present in the + * system is in a driver's list of supported devices. Returns 1 if supported, + * and 0 if there is no match. + */ + +static int dio_bus_match(struct device *dev, const struct device_driver *drv) +{ + struct dio_dev *d = to_dio_dev(dev); + const struct dio_driver *dio_drv = to_dio_driver(drv); + const struct dio_device_id *ids = dio_drv->id_table; + + if (!ids) + return 0; + + return dio_match_device(ids, d) ? 1 : 0; +} + + +const struct bus_type dio_bus_type = { + .name = "dio", + .match = dio_bus_match, + .probe = dio_device_probe, +}; + + +static int __init dio_driver_init(void) +{ + return bus_register(&dio_bus_type); +} + +postcore_initcall(dio_driver_init); + +EXPORT_SYMBOL(dio_register_driver); +EXPORT_SYMBOL(dio_unregister_driver); +EXPORT_SYMBOL(dio_bus_type); -- cgit v1.3.1