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270 lines
7.3 KiB
270 lines
7.3 KiB
/****************************************************************************** |
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* Xen balloon driver - enables returning/claiming memory to/from Xen. |
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* |
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* Copyright (c) 2003, B Dragovic |
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* Copyright (c) 2003-2004, M Williamson, K Fraser |
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* Copyright (c) 2005 Dan M. Smith, IBM Corporation |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License version 2 |
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* as published by the Free Software Foundation; or, when distributed |
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* separately from the Linux kernel or incorporated into other |
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* software packages, subject to the following license: |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this source file (the "Software"), to deal in the Software without |
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* restriction, including without limitation the rights to use, copy, modify, |
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* merge, publish, distribute, sublicense, and/or sell copies of the Software, |
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* and to permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in |
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* all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
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* IN THE SOFTWARE. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/mm_types.h> |
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#include <linux/init.h> |
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#include <linux/capability.h> |
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#include <linux/memory_hotplug.h> |
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#include <xen/xen.h> |
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#include <xen/interface/xen.h> |
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#include <xen/balloon.h> |
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#include <xen/xenbus.h> |
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#include <xen/features.h> |
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#include <xen/page.h> |
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#include <xen/mem-reservation.h> |
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#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) |
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#define BALLOON_CLASS_NAME "xen_memory" |
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#ifdef CONFIG_MEMORY_HOTPLUG |
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u64 xen_saved_max_mem_size = 0; |
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#endif |
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static struct device balloon_dev; |
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static int register_balloon(struct device *dev); |
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/* React to a change in the target key */ |
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static void watch_target(struct xenbus_watch *watch, |
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const char *path, const char *token) |
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{ |
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unsigned long long new_target, static_max; |
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int err; |
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static bool watch_fired; |
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static long target_diff; |
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#ifdef CONFIG_MEMORY_HOTPLUG |
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/* The balloon driver will take care of adding memory now. */ |
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if (xen_saved_max_mem_size) |
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max_mem_size = xen_saved_max_mem_size; |
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#endif |
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err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target); |
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if (err != 1) { |
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/* This is ok (for domain0 at least) - so just return */ |
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return; |
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} |
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/* The given memory/target value is in KiB, so it needs converting to |
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* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10. |
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*/ |
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new_target >>= PAGE_SHIFT - 10; |
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if (!watch_fired) { |
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watch_fired = true; |
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if ((xenbus_scanf(XBT_NIL, "memory", "static-max", |
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"%llu", &static_max) == 1) || |
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(xenbus_scanf(XBT_NIL, "memory", "memory_static_max", |
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"%llu", &static_max) == 1)) |
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static_max >>= PAGE_SHIFT - 10; |
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else |
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static_max = balloon_stats.current_pages; |
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target_diff = (xen_pv_domain() || xen_initial_domain()) ? 0 |
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: static_max - balloon_stats.target_pages; |
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} |
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balloon_set_new_target(new_target - target_diff); |
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} |
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static struct xenbus_watch target_watch = { |
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.node = "memory/target", |
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.callback = watch_target, |
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}; |
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static int balloon_init_watcher(struct notifier_block *notifier, |
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unsigned long event, |
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void *data) |
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{ |
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int err; |
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err = register_xenbus_watch(&target_watch); |
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if (err) |
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pr_err("Failed to set balloon watcher\n"); |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block xenstore_notifier = { |
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.notifier_call = balloon_init_watcher, |
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}; |
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void xen_balloon_init(void) |
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{ |
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register_balloon(&balloon_dev); |
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register_xenstore_notifier(&xenstore_notifier); |
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} |
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EXPORT_SYMBOL_GPL(xen_balloon_init); |
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#define BALLOON_SHOW(name, format, args...) \ |
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static ssize_t show_##name(struct device *dev, \ |
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struct device_attribute *attr, \ |
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char *buf) \ |
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{ \ |
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return sprintf(buf, format, ##args); \ |
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} \ |
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static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL) |
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BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages)); |
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BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low)); |
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BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high)); |
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static DEVICE_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay); |
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static DEVICE_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay); |
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static DEVICE_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count); |
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static DEVICE_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count); |
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static DEVICE_BOOL_ATTR(scrub_pages, 0644, xen_scrub_pages); |
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static ssize_t show_target_kb(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages)); |
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} |
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static ssize_t store_target_kb(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, |
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size_t count) |
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{ |
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char *endchar; |
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unsigned long long target_bytes; |
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if (!capable(CAP_SYS_ADMIN)) |
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return -EPERM; |
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target_bytes = simple_strtoull(buf, &endchar, 0) * 1024; |
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balloon_set_new_target(target_bytes >> PAGE_SHIFT); |
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return count; |
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} |
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static DEVICE_ATTR(target_kb, S_IRUGO | S_IWUSR, |
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show_target_kb, store_target_kb); |
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static ssize_t show_target(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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return sprintf(buf, "%llu\n", |
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(unsigned long long)balloon_stats.target_pages |
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<< PAGE_SHIFT); |
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} |
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static ssize_t store_target(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, |
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size_t count) |
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{ |
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char *endchar; |
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unsigned long long target_bytes; |
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if (!capable(CAP_SYS_ADMIN)) |
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return -EPERM; |
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target_bytes = memparse(buf, &endchar); |
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balloon_set_new_target(target_bytes >> PAGE_SHIFT); |
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return count; |
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} |
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static DEVICE_ATTR(target, S_IRUGO | S_IWUSR, |
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show_target, store_target); |
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static struct attribute *balloon_attrs[] = { |
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&dev_attr_target_kb.attr, |
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&dev_attr_target.attr, |
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&dev_attr_schedule_delay.attr.attr, |
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&dev_attr_max_schedule_delay.attr.attr, |
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&dev_attr_retry_count.attr.attr, |
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&dev_attr_max_retry_count.attr.attr, |
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&dev_attr_scrub_pages.attr.attr, |
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NULL |
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}; |
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static const struct attribute_group balloon_group = { |
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.attrs = balloon_attrs |
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}; |
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static struct attribute *balloon_info_attrs[] = { |
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&dev_attr_current_kb.attr, |
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&dev_attr_low_kb.attr, |
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&dev_attr_high_kb.attr, |
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NULL |
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}; |
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static const struct attribute_group balloon_info_group = { |
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.name = "info", |
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.attrs = balloon_info_attrs |
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}; |
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static const struct attribute_group *balloon_groups[] = { |
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&balloon_group, |
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&balloon_info_group, |
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NULL |
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}; |
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static struct bus_type balloon_subsys = { |
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.name = BALLOON_CLASS_NAME, |
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.dev_name = BALLOON_CLASS_NAME, |
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}; |
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static int register_balloon(struct device *dev) |
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{ |
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int error; |
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error = subsys_system_register(&balloon_subsys, NULL); |
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if (error) |
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return error; |
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dev->id = 0; |
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dev->bus = &balloon_subsys; |
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dev->groups = balloon_groups; |
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error = device_register(dev); |
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if (error) { |
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bus_unregister(&balloon_subsys); |
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return error; |
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} |
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return 0; |
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}
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