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io_uring: fix SQPOLL thread handling over exec

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Just like the changes for io-wq, ensure that we re-fork the SQPOLL
thread if the owner execs. Mark the ctx sq thread as sqo_exec if
it dies, and the ring as needing a wakeup which will force the task
to enter the kernel. When it does, setup the new thread and proceed
as usual.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-02-25 10:17:46 -07:00
parent 4fb6ac3262
commit 5f3f26f98a
1 changed files with 34 additions and 1 deletions
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35
fs/io_uring.c
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@ -339,6 +339,7 @@ struct io_ring_ctx {
unsigned int eventfd_async: 1;
unsigned int restricted: 1;
unsigned int sqo_dead: 1;
unsigned int sqo_exec: 1;
/*
* Ring buffer of indices into array of io_uring_sqe, which is
@ -6796,6 +6797,10 @@ static int io_sq_thread(void *data)
complete_all(&sqd->completion);
mutex_lock(&sqd->lock);
sqd->thread = NULL;
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
ctx->sqo_exec = 1;
io_ring_set_wakeup_flag(ctx);
}
mutex_unlock(&sqd->lock);
complete(&sqd->exited);
@ -7840,6 +7845,25 @@ void __io_uring_free(struct task_struct *tsk)
tsk->io_uring = NULL;
}
static int io_sq_thread_fork(struct io_sq_data *sqd, struct io_ring_ctx *ctx)
{
int ret;
clear_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
reinit_completion(&sqd->completion);
ctx->sqo_dead = ctx->sqo_exec = 0;
sqd->task_pid = current->pid;
current->flags |= PF_IO_WORKER;
ret = io_wq_fork_thread(io_sq_thread, sqd);
current->flags &= ~PF_IO_WORKER;
if (ret < 0) {
sqd->thread = NULL;
return ret;
}
wait_for_completion(&sqd->completion);
return io_uring_alloc_task_context(sqd->thread, ctx);
}
static int io_sq_offload_create(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
@ -9128,6 +9152,12 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
if (ctx->flags & IORING_SETUP_SQPOLL) {
io_cqring_overflow_flush(ctx, false, NULL, NULL);
if (unlikely(ctx->sqo_exec)) {
ret = io_sq_thread_fork(ctx->sq_data, ctx);
if (ret)
goto out;
ctx->sqo_exec = 0;
}
ret = -EOWNERDEAD;
if (unlikely(ctx->sqo_dead))
goto out;
@ -9229,8 +9259,11 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
*/
has_lock = mutex_trylock(&ctx->uring_lock);
if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL))
if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) {
sq = ctx->sq_data;
if (!sq->thread)
sq = NULL;
}
seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);