From cbcf72148da4af55ea81cfb351ea7c026ff1014f Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Sat, 18 Jul 2020 11:31:21 +0300
Subject: io_uring: return locked and pinned page accounting
Locked and pinned memory accounting in io_{,un}account_mem() depends on
having ->sqo_mm, which is NULL after a recent change for non SQPOLL'ed
io_ring. That disables the accounting.
Return ->sqo_mm initialisation back, and do __io_sq_thread_acquire_mm()
based on IORING_SETUP_SQPOLL flag.
Fixes: 8eb06d7e8dd85 ("io_uring: fix missing ->mm on exit")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
(limited to 'fs/io_uring.c')
diff --git a/fs/io_uring.c b/fs/io_uring.c
index ba7ce103667b..680b16f71a03 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -981,7 +981,8 @@ static void io_sq_thread_drop_mm(void)
static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx)
{
if (!current->mm) {
- if (unlikely(!ctx->sqo_mm || !mmget_not_zero(ctx->sqo_mm)))
+ if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL) ||
+ !mmget_not_zero(ctx->sqo_mm)))
return -EFAULT;
kthread_use_mm(ctx->sqo_mm);
}
@@ -7259,10 +7260,10 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
{
int ret;
- if (ctx->flags & IORING_SETUP_SQPOLL) {
- mmgrab(current->mm);
- ctx->sqo_mm = current->mm;
+ mmgrab(current->mm);
+ ctx->sqo_mm = current->mm;
+ if (ctx->flags & IORING_SETUP_SQPOLL) {
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto err;
--
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