| .. | .. |
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| 10 | 10 | #include <linux/interrupt.h> |
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| 11 | 11 | #include <linux/irq.h> |
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| 12 | 12 | #include <linux/kernel.h> |
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| 13 | +#include <linux/kobject.h> |
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| 13 | 14 | #include <linux/kthread.h> |
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| 14 | 15 | #include <linux/module.h> |
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| 15 | 16 | #include <linux/printk.h> |
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| 16 | 17 | #include <linux/string.h> |
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| 18 | +#include <linux/sysfs.h> |
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| 19 | +#include <linux/completion.h> |
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| 17 | 20 | |
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| 18 | 21 | static ulong delay = 100; |
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| 19 | | -static char test_mode[10] = "irq"; |
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| 22 | +static char test_mode[12] = "irq"; |
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| 23 | +static uint burst_size = 1; |
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| 20 | 24 | |
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| 21 | | -module_param_named(delay, delay, ulong, S_IRUGO); |
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| 22 | | -module_param_string(test_mode, test_mode, 10, S_IRUGO); |
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| 23 | | -MODULE_PARM_DESC(delay, "Period in microseconds (100 uS default)"); |
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| 24 | | -MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt or irq (default irq)"); |
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| 25 | +module_param_named(delay, delay, ulong, 0444); |
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| 26 | +module_param_string(test_mode, test_mode, 12, 0444); |
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| 27 | +module_param_named(burst_size, burst_size, uint, 0444); |
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| 28 | +MODULE_PARM_DESC(delay, "Period in microseconds (100 us default)"); |
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| 29 | +MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt, irq, or alternate (default irq)"); |
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| 30 | +MODULE_PARM_DESC(burst_size, "The size of a burst (default 1)"); |
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| 31 | + |
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| 32 | +static struct completion done; |
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| 33 | + |
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| 34 | +#define MIN(x, y) ((x) < (y) ? (x) : (y)) |
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| 25 | 35 | |
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| 26 | 36 | static void busy_wait(ulong time) |
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| 27 | 37 | { |
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| .. | .. |
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| 34 | 44 | } while ((end - start) < (time * 1000)); |
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| 35 | 45 | } |
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| 36 | 46 | |
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| 37 | | -static int preemptirq_delay_run(void *data) |
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| 47 | +static __always_inline void irqoff_test(void) |
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| 38 | 48 | { |
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| 39 | 49 | unsigned long flags; |
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| 50 | + local_irq_save(flags); |
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| 51 | + busy_wait(delay); |
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| 52 | + local_irq_restore(flags); |
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| 53 | +} |
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| 40 | 54 | |
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| 41 | | - if (!strcmp(test_mode, "irq")) { |
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| 42 | | - local_irq_save(flags); |
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| 43 | | - busy_wait(delay); |
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| 44 | | - local_irq_restore(flags); |
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| 45 | | - } else if (!strcmp(test_mode, "preempt")) { |
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| 46 | | - preempt_disable(); |
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| 47 | | - busy_wait(delay); |
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| 48 | | - preempt_enable(); |
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| 55 | +static __always_inline void preemptoff_test(void) |
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| 56 | +{ |
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| 57 | + preempt_disable(); |
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| 58 | + busy_wait(delay); |
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| 59 | + preempt_enable(); |
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| 60 | +} |
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| 61 | + |
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| 62 | +static void execute_preemptirqtest(int idx) |
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| 63 | +{ |
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| 64 | + if (!strcmp(test_mode, "irq")) |
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| 65 | + irqoff_test(); |
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| 66 | + else if (!strcmp(test_mode, "preempt")) |
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| 67 | + preemptoff_test(); |
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| 68 | + else if (!strcmp(test_mode, "alternate")) { |
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| 69 | + if (idx % 2 == 0) |
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| 70 | + irqoff_test(); |
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| 71 | + else |
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| 72 | + preemptoff_test(); |
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| 49 | 73 | } |
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| 74 | +} |
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| 75 | + |
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| 76 | +#define DECLARE_TESTFN(POSTFIX) \ |
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| 77 | + static void preemptirqtest_##POSTFIX(int idx) \ |
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| 78 | + { \ |
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| 79 | + execute_preemptirqtest(idx); \ |
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| 80 | + } \ |
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| 81 | + |
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| 82 | +/* |
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| 83 | + * We create 10 different functions, so that we can get 10 different |
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| 84 | + * backtraces. |
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| 85 | + */ |
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| 86 | +DECLARE_TESTFN(0) |
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| 87 | +DECLARE_TESTFN(1) |
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| 88 | +DECLARE_TESTFN(2) |
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| 89 | +DECLARE_TESTFN(3) |
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| 90 | +DECLARE_TESTFN(4) |
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| 91 | +DECLARE_TESTFN(5) |
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| 92 | +DECLARE_TESTFN(6) |
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| 93 | +DECLARE_TESTFN(7) |
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| 94 | +DECLARE_TESTFN(8) |
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| 95 | +DECLARE_TESTFN(9) |
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| 96 | + |
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| 97 | +static void (*testfuncs[])(int) = { |
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| 98 | + preemptirqtest_0, |
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| 99 | + preemptirqtest_1, |
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| 100 | + preemptirqtest_2, |
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| 101 | + preemptirqtest_3, |
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| 102 | + preemptirqtest_4, |
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| 103 | + preemptirqtest_5, |
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| 104 | + preemptirqtest_6, |
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| 105 | + preemptirqtest_7, |
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| 106 | + preemptirqtest_8, |
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| 107 | + preemptirqtest_9, |
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| 108 | +}; |
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| 109 | + |
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| 110 | +#define NR_TEST_FUNCS ARRAY_SIZE(testfuncs) |
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| 111 | + |
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| 112 | +static int preemptirq_delay_run(void *data) |
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| 113 | +{ |
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| 114 | + int i; |
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| 115 | + int s = MIN(burst_size, NR_TEST_FUNCS); |
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| 116 | + |
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| 117 | + for (i = 0; i < s; i++) |
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| 118 | + (testfuncs[i])(i); |
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| 119 | + |
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| 120 | + complete(&done); |
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| 121 | + |
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| 122 | + set_current_state(TASK_INTERRUPTIBLE); |
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| 123 | + while (!kthread_should_stop()) { |
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| 124 | + schedule(); |
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| 125 | + set_current_state(TASK_INTERRUPTIBLE); |
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| 126 | + } |
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| 127 | + |
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| 128 | + __set_current_state(TASK_RUNNING); |
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| 50 | 129 | |
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| 51 | 130 | return 0; |
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| 52 | 131 | } |
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| 53 | 132 | |
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| 54 | | -static int __init preemptirq_delay_init(void) |
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| 133 | +static int preemptirq_run_test(void) |
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| 55 | 134 | { |
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| 135 | + struct task_struct *task; |
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| 56 | 136 | char task_name[50]; |
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| 57 | | - struct task_struct *test_task; |
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| 137 | + |
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| 138 | + init_completion(&done); |
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| 58 | 139 | |
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| 59 | 140 | snprintf(task_name, sizeof(task_name), "%s_test", test_mode); |
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| 141 | + task = kthread_run(preemptirq_delay_run, NULL, task_name); |
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| 142 | + if (IS_ERR(task)) |
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| 143 | + return PTR_ERR(task); |
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| 144 | + if (task) { |
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| 145 | + wait_for_completion(&done); |
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| 146 | + kthread_stop(task); |
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| 147 | + } |
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| 148 | + return 0; |
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| 149 | +} |
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| 60 | 150 | |
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| 61 | | - test_task = kthread_run(preemptirq_delay_run, NULL, task_name); |
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| 62 | | - return PTR_ERR_OR_ZERO(test_task); |
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| 151 | + |
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| 152 | +static ssize_t trigger_store(struct kobject *kobj, struct kobj_attribute *attr, |
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| 153 | + const char *buf, size_t count) |
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| 154 | +{ |
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| 155 | + ssize_t ret; |
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| 156 | + |
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| 157 | + ret = preemptirq_run_test(); |
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| 158 | + if (ret) |
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| 159 | + return ret; |
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| 160 | + return count; |
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| 161 | +} |
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| 162 | + |
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| 163 | +static struct kobj_attribute trigger_attribute = |
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| 164 | + __ATTR(trigger, 0200, NULL, trigger_store); |
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| 165 | + |
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| 166 | +static struct attribute *attrs[] = { |
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| 167 | + &trigger_attribute.attr, |
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| 168 | + NULL, |
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| 169 | +}; |
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| 170 | + |
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| 171 | +static struct attribute_group attr_group = { |
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| 172 | + .attrs = attrs, |
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| 173 | +}; |
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| 174 | + |
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| 175 | +static struct kobject *preemptirq_delay_kobj; |
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| 176 | + |
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| 177 | +static int __init preemptirq_delay_init(void) |
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| 178 | +{ |
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| 179 | + int retval; |
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| 180 | + |
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| 181 | + retval = preemptirq_run_test(); |
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| 182 | + if (retval != 0) |
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| 183 | + return retval; |
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| 184 | + |
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| 185 | + preemptirq_delay_kobj = kobject_create_and_add("preemptirq_delay_test", |
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| 186 | + kernel_kobj); |
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| 187 | + if (!preemptirq_delay_kobj) |
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| 188 | + return -ENOMEM; |
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| 189 | + |
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| 190 | + retval = sysfs_create_group(preemptirq_delay_kobj, &attr_group); |
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| 191 | + if (retval) |
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| 192 | + kobject_put(preemptirq_delay_kobj); |
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| 193 | + |
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| 194 | + return retval; |
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| 63 | 195 | } |
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| 64 | 196 | |
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| 65 | 197 | static void __exit preemptirq_delay_exit(void) |
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| 66 | 198 | { |
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| 67 | | - return; |
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| 199 | + kobject_put(preemptirq_delay_kobj); |
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| 68 | 200 | } |
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| 69 | 201 | |
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| 70 | 202 | module_init(preemptirq_delay_init) |
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