When we test S4(suspend to disk) on LoongArch 3A6000 platform, the test case sometimes fails. The dmesg log shows the following error: Invalid LZO compressed length After we dig into the code, we find out that: When compress/decompress the image, the synchronization operation between the control thread and the compress/decompress/crc thread uses relaxed ordering interface, which is unreliable, and the following situation may occur: CPU 0 CPU 1 save_image_lzo lzo_compress_threadfn atomic_set(&d->stop, 1); atomic_read(&data[thr].stop) data[thr].cmp = data[thr].cmp_len; WRITE data[thr].cmp_len Then CPU0 get a old cmp_len and write to disk. When cpu resume from S4, wrong cmp_len is loaded.
To maintain data consistency between two threads, we should use the acquire/release ordering interface. So we change atomic_read/atomic_set to atomic_read_acquire/atomic_set_release.
Signed-off-by: Hongchen Zhang zhanghongchen@loongson.cn Signed-off-by: Weihao Li liweihao@loongson.cn --- kernel/power/swap.c | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/kernel/power/swap.c b/kernel/power/swap.c index a2cb0babb5ec..d44f5937f1e5 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -606,11 +606,11 @@ static int crc32_threadfn(void *data) unsigned i;
while (1) { - wait_event(d->go, atomic_read(&d->ready) || + wait_event(d->go, atomic_read_acquire(&d->ready) || kthread_should_stop()); if (kthread_should_stop()) { d->thr = NULL; - atomic_set(&d->stop, 1); + atomic_set_release(&d->stop, 1); wake_up(&d->done); break; } @@ -619,7 +619,7 @@ static int crc32_threadfn(void *data) for (i = 0; i < d->run_threads; i++) *d->crc32 = crc32_le(*d->crc32, d->unc[i], *d->unc_len[i]); - atomic_set(&d->stop, 1); + atomic_set_release(&d->stop, 1); wake_up(&d->done); } return 0; @@ -649,12 +649,12 @@ static int lzo_compress_threadfn(void *data) struct cmp_data *d = data;
while (1) { - wait_event(d->go, atomic_read(&d->ready) || + wait_event(d->go, atomic_read_acquire(&d->ready) || kthread_should_stop()); if (kthread_should_stop()) { d->thr = NULL; d->ret = -1; - atomic_set(&d->stop, 1); + atomic_set_release(&d->stop, 1); wake_up(&d->done); break; } @@ -663,7 +663,7 @@ static int lzo_compress_threadfn(void *data) d->ret = lzo1x_1_compress(d->unc, d->unc_len, d->cmp + LZO_HEADER, &d->cmp_len, d->wrk); - atomic_set(&d->stop, 1); + atomic_set_release(&d->stop, 1); wake_up(&d->done); } return 0; @@ -798,7 +798,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
data[thr].unc_len = off;
- atomic_set(&data[thr].ready, 1); + atomic_set_release(&data[thr].ready, 1); wake_up(&data[thr].go); }
@@ -806,12 +806,12 @@ static int save_image_lzo(struct swap_map_handle *handle, break;
crc->run_threads = thr; - atomic_set(&crc->ready, 1); + atomic_set_release(&crc->ready, 1); wake_up(&crc->go);
for (run_threads = thr, thr = 0; thr < run_threads; thr++) { wait_event(data[thr].done, - atomic_read(&data[thr].stop)); + atomic_read_acquire(&data[thr].stop)); atomic_set(&data[thr].stop, 0);
ret = data[thr].ret; @@ -850,7 +850,7 @@ static int save_image_lzo(struct swap_map_handle *handle, } }
- wait_event(crc->done, atomic_read(&crc->stop)); + wait_event(crc->done, atomic_read_acquire(&crc->stop)); atomic_set(&crc->stop, 0); }
@@ -1132,12 +1132,12 @@ static int lzo_decompress_threadfn(void *data) struct dec_data *d = data;
while (1) { - wait_event(d->go, atomic_read(&d->ready) || + wait_event(d->go, atomic_read_acquire(&d->ready) || kthread_should_stop()); if (kthread_should_stop()) { d->thr = NULL; d->ret = -1; - atomic_set(&d->stop, 1); + atomic_set_release(&d->stop, 1); wake_up(&d->done); break; } @@ -1150,7 +1150,7 @@ static int lzo_decompress_threadfn(void *data) flush_icache_range((unsigned long)d->unc, (unsigned long)d->unc + d->unc_len);
- atomic_set(&d->stop, 1); + atomic_set_release(&d->stop, 1); wake_up(&d->done); } return 0; @@ -1335,7 +1335,7 @@ static int load_image_lzo(struct swap_map_handle *handle, }
if (crc->run_threads) { - wait_event(crc->done, atomic_read(&crc->stop)); + wait_event(crc->done, atomic_read_acquire(&crc->stop)); atomic_set(&crc->stop, 0); crc->run_threads = 0; } @@ -1371,7 +1371,7 @@ static int load_image_lzo(struct swap_map_handle *handle, pg = 0; }
- atomic_set(&data[thr].ready, 1); + atomic_set_release(&data[thr].ready, 1); wake_up(&data[thr].go); }
@@ -1390,7 +1390,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
for (run_threads = thr, thr = 0; thr < run_threads; thr++) { wait_event(data[thr].done, - atomic_read(&data[thr].stop)); + atomic_read_acquire(&data[thr].stop)); atomic_set(&data[thr].stop, 0);
ret = data[thr].ret; @@ -1421,7 +1421,7 @@ static int load_image_lzo(struct swap_map_handle *handle, ret = snapshot_write_next(snapshot); if (ret <= 0) { crc->run_threads = thr + 1; - atomic_set(&crc->ready, 1); + atomic_set_release(&crc->ready, 1); wake_up(&crc->go); goto out_finish; } @@ -1429,13 +1429,13 @@ static int load_image_lzo(struct swap_map_handle *handle, }
crc->run_threads = thr; - atomic_set(&crc->ready, 1); + atomic_set_release(&crc->ready, 1); wake_up(&crc->go); }
out_finish: if (crc->run_threads) { - wait_event(crc->done, atomic_read(&crc->stop)); + wait_event(crc->done, atomic_read_acquire(&crc->stop)); atomic_set(&crc->stop, 0); } stop = ktime_get();