Kernel utility functions

upper_32_bits — return bits 32-63 of a number
lower_32_bits — return bits 0-31 of a number
might_sleep — annotation for functions that can sleep
abs — return absolute value of an argument
reciprocal_scale — "scale" a value into range [0, ep_ro)
kstrtoul — convert a string to an unsigned long
kstrtol — convert a string to a long
trace_printk — printf formatting in the ftrace buffer
trace_puts — write a string into the ftrace buffer
min_not_zero — return the minimum that is _not_ zero, unless both are zero
clamp — return a value clamped to a given range with strict typechecking
clamp_t — return a value clamped to a given range using a given type
clamp_val — return a value clamped to a given range using val's type
container_of — cast a member of a structure out to the containing structure
printk — print a kernel message
console_lock — lock the console system for exclusive use.
console_trylock — try to lock the console system for exclusive use.
console_unlock — unlock the console system
console_conditional_schedule — yield the CPU if required
printk_timed_ratelimit — caller-controlled printk ratelimiting
kmsg_dump_register — register a kernel log dumper.
kmsg_dump_unregister — unregister a kmsg dumper.
kmsg_dump_get_line — retrieve one kmsg log line
kmsg_dump_get_buffer — copy kmsg log lines
kmsg_dump_rewind — reset the interator
panic — halt the system
kernel/sys.c — Document generation inconsistency
init_srcu_struct — initialize a sleep-RCU structure
cleanup_srcu_struct — deconstruct a sleep-RCU structure
synchronize_srcu — wait for prior SRCU read-side critical-section completion
synchronize_srcu_expedited — Brute-force SRCU grace period
srcu_barrier — Wait until all in-flight call_srcu callbacks complete.
srcu_batches_completed — return batches completed.
rcu_idle_enter — inform RCU that current CPU is entering idle
rcu_idle_exit — inform RCU that current CPU is leaving idle
rcu_is_watching — see if RCU thinks that the current CPU is idle
synchronize_sched — wait until an rcu-sched grace period has elapsed.
synchronize_rcu_bh — wait until an rcu_bh grace period has elapsed.
get_state_synchronize_rcu — Snapshot current RCU state
cond_synchronize_rcu — Conditionally wait for an RCU grace period
get_state_synchronize_sched — Snapshot current RCU-sched state
cond_synchronize_sched — Conditionally wait for an RCU-sched grace period
rcu_barrier_bh — Wait until all in-flight call_rcu_bh callbacks complete.
rcu_barrier_sched — Wait for in-flight call_rcu_sched callbacks.
synchronize_rcu — wait until a grace period has elapsed.
rcu_barrier — Wait until all in-flight call_rcu callbacks complete.
rcu_read_lock_sched_held — might we be in RCU-sched read-side critical section?
rcu_expedite_gp — Expedite future RCU grace periods
rcu_unexpedite_gp — Cancel prior rcu_expedite_gp invocation
rcu_read_lock_held — might we be in RCU read-side critical section?
rcu_read_lock_bh_held — might we be in RCU-bh read-side critical section?
wakeme_after_rcu — Callback function to awaken a task after grace period
init_rcu_head_on_stack — initialize on-stack rcu_head for debugobjects
destroy_rcu_head_on_stack — destroy on-stack rcu_head for debugobjects
synchronize_rcu_tasks — wait until an rcu-tasks grace period has elapsed.
rcu_barrier_tasks — Wait for in-flight call_rcu_tasks callbacks.