| // SPDX-License-Identifier: GPL-2.0 |
| |
| #include <linux/export.h> |
| #include <linux/interrupt.h> |
| |
| #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) |
| /* |
| * Do not use in new code. Waiting for tasklets from atomic contexts is |
| * error prone and should be avoided. |
| */ |
| void tasklet_unlock_spin_wait(struct tasklet_struct *t) |
| { |
| while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { |
| if (IS_ENABLED(CONFIG_PREEMPT_RT)) { |
| /* |
| * Prevent a live lock when current preempted soft |
| * interrupt processing or prevents ksoftirqd from |
| * running. If the tasklet runs on a different CPU |
| * then this has no effect other than doing the BH |
| * disable/enable dance for nothing. |
| */ |
| local_bh_disable(); |
| local_bh_enable(); |
| } else { |
| cpu_relax(); |
| } |
| } |
| } |
| EXPORT_SYMBOL_GPL(tasklet_unlock_spin_wait); |
| #endif |
