Eric Lee / smarc-fsl-linux-kernel

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Commit 3eac4abaa69949af0e2f64e5c55ee8a22bbdd3e7

Authored by Kevin Hilman
Committed by Linus Torvalds
1 parent 04287f975e
Exists in master and in 39 other branches 8mp-imx_5.4.70_2.3.0, 8qm-imx_5.4.70_2.3.0, emb_imx_lf-5.15.y, emb_lf-6.1.y, imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, imx_4.1.15_1.0.0_ga, pitx_8mp_lf-5.10.y, rt-smarc-imx_4.1.15_1.0.0_ga, rt_linux_5.15.71, smarc-8m-android-11.0.0_2.0.0, smarc-imx6_4.14.98_2.0.0_ga, smarc-imx6_4.9.88_2.0.0_ga, smarc-imx7_4.14.98_2.0.0_ga, smarc-imx7_4.9.11_1.0.0_ga, smarc-imx7_4.9.88_2.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-imx_4.1.15_1.0.0_ga, smarc-imx_4.9.11_1.0.0_ga, smarc-imx_4.9.51_imx8m_ga, smarc-imx_4.9.88_2.0.0_ga, smarc-m6.0.1_2.1.0-ga, smarc-n7.1.2_2.0.0-ga, smarc-rel_imx_4.1.15_1.2.0_ga, smarc_8m_00d0_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.14.78_1.0.0_ga, smarc_8m_imx_4.14.98_2.0.0_ga, smarc_8m_imx_4.19.35_1.1.0, smarc_8mm_imx_4.14.78_1.0.0_ga, smarc_8mm_imx_4.14.98_2.0.0_ga, smarc_8mm_imx_4.19.35_1.1.0, smarc_8mm_imx_5.4.24_2.1.0, smarc_8mp_lf-5.10.y, smarc_8mq_imx_5.4.24_2.1.0, smarc_8mq_lf-5.10.y, smarc_imx_lf-5.15.y

rwsem generic spinlock: use IRQ save/restore spinlocks 

rwsems can be used with IRQs disabled, particularily in early boot
before IRQs are enabled.  Currently the spin_unlock_irq() usage in the
slow-patch will unconditionally enable interrupts and cause problems
since interrupts are not yet initialized or enabled.

This patch uses save/restore versions of IRQ spinlocks in the slowpath
to ensure interrupts are not unintentionally disabled.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 8 additions and 6 deletions Side-by-side Diff

lib/rwsem-spinlock.c
Diff comments   View file @ 3eac4ab
... ... @@ -143,13 +143,14 @@
143 143 {
144 144 struct rwsem_waiter waiter;
145 145 struct task_struct *tsk;
  146 + unsigned long flags;
146 147  
147   - spin_lock_irq(&sem->wait_lock);
  148 + spin_lock_irqsave(&sem->wait_lock, flags);
148 149  
149 150 if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
150 151 /* granted */
151 152 sem->activity++;
152   - spin_unlock_irq(&sem->wait_lock);
  153 + spin_unlock_irqrestore(&sem->wait_lock, flags);
153 154 goto out;
154 155 }
155 156  
... ... @@ -164,7 +165,7 @@
164 165 list_add_tail(&waiter.list, &sem->wait_list);
165 166  
166 167 /* we don't need to touch the semaphore struct anymore */
167   - spin_unlock_irq(&sem->wait_lock);
  168 + spin_unlock_irqrestore(&sem->wait_lock, flags);
168 169  
169 170 /* wait to be given the lock */
170 171 for (;;) {
171 172  
172 173  
... ... @@ -209,13 +210,14 @@
209 210 {
210 211 struct rwsem_waiter waiter;
211 212 struct task_struct *tsk;
  213 + unsigned long flags;
212 214  
213   - spin_lock_irq(&sem->wait_lock);
  215 + spin_lock_irqsave(&sem->wait_lock, flags);
214 216  
215 217 if (sem->activity == 0 && list_empty(&sem->wait_list)) {
216 218 /* granted */
217 219 sem->activity = -1;
218   - spin_unlock_irq(&sem->wait_lock);
  220 + spin_unlock_irqrestore(&sem->wait_lock, flags);
219 221 goto out;
220 222 }
221 223  
... ... @@ -230,7 +232,7 @@
230 232 list_add_tail(&waiter.list, &sem->wait_list);
231 233  
232 234 /* we don't need to touch the semaphore struct anymore */
233   - spin_unlock_irq(&sem->wait_lock);
  235 + spin_unlock_irqrestore(&sem->wait_lock, flags);
234 236  
235 237 /* wait to be given the lock */
236 238 for (;;) {