We go through various hoops to disallow signals for the IO threads, but
there's really no reason why we cannot just allow them. The IO threads
never return to userspace like a normal thread, and hence don't go through
normal signal processing. Instead, just check for a pending signal as part
of the work loop, and call get_signal() to handle it for us if anything
is pending.
With that, we can support receiving signals, including special ones like
SIGSTOP.
Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
fs/io-wq.c | 24 +++++++++++++++++-------
fs/io_uring.c | 12 ++++++++----
2 files changed, 25 insertions(+), 11 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index b7c1fa932cb3..3e2f059a1737 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -16,7 +16,6 @@
#include <linux/rculist_nulls.h>
#include <linux/cpu.h>
#include <linux/tracehook.h>
-#include <linux/freezer.h>
#include "../kernel/sched/sched.h"
#include "io-wq.h"
@@ -503,10 +502,16 @@ static int io_wqe_worker(void *data)
if (io_flush_signals())
continue;
ret = schedule_timeout(WORKER_IDLE_TIMEOUT);
- if (try_to_freeze() || ret)
+ if (signal_pending(current)) {
+ struct ksignal ksig;
+
+ if (fatal_signal_pending(current))
+ break;
+ if (get_signal(&ksig))
+ continue;
+ }
+ if (ret)
continue;
- if (fatal_signal_pending(current))
- break;
/* timed out, exit unless we're the fixed worker */
if (test_bit(IO_WQ_BIT_EXIT, &wq->state) ||
!(worker->flags & IO_WORKER_F_FIXED))
@@ -714,9 +719,14 @@ static int io_wq_manager(void *data)
set_current_state(TASK_INTERRUPTIBLE);
io_wq_check_workers(wq);
schedule_timeout(HZ);
- try_to_freeze();
- if (fatal_signal_pending(current))
- set_bit(IO_WQ_BIT_EXIT, &wq->state);
+ if (signal_pending(current)) {
+ struct ksignal ksig;
+
+ if (fatal_signal_pending(current))
+ set_bit(IO_WQ_BIT_EXIT, &wq->state);
+ else if (get_signal(&ksig))
+ continue;
+ }
} while (!test_bit(IO_WQ_BIT_EXIT, &wq->state));
io_wq_check_workers(wq);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 54ea561db4a5..350418a88db3 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -78,7 +78,6 @@
#include <linux/task_work.h>
#include <linux/pagemap.h>
#include <linux/io_uring.h>
-#include <linux/freezer.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
@@ -6765,8 +6764,14 @@ static int io_sq_thread(void *data)
timeout = jiffies + sqd->sq_thread_idle;
continue;
}
- if (fatal_signal_pending(current))
- break;
+ if (signal_pending(current)) {
+ struct ksignal ksig;
+
+ if (fatal_signal_pending(current))
+ break;
+ if (get_signal(&ksig))
+ continue;
+ }
sqt_spin = false;
cap_entries = !list_is_singular(&sqd->ctx_list);
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
@@ -6809,7 +6814,6 @@ static int io_sq_thread(void *data)
mutex_unlock(&sqd->lock);
schedule();
- try_to_freeze();
mutex_lock(&sqd->lock);
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
io_ring_clear_wakeup_flag(ctx);
--
2.31.0
