[PATCH 5.10 07/54] io_uring: account io_uring internal files as REQ_F_INFLIGHT

[Greg Kroah-Hartman]

From: Jens Axboe <ax...@kernel.dk>

[ Upstream commit 02a13674fa0e8dd326de8b9f4514b41b03d99003 ]

We need to actively cancel anything that introduces a potential circular
loop, where io_uring holds a reference to itself. If the file in question
is an io_uring file, then add the request to the inflight list.

Cc: sta...@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.sile...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 fs/io_uring.c |   32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1000,6 +1000,9 @@ static inline void io_clean_op(struct io
 static inline bool __io_match_files(struct io_kiocb *req,
                                    struct files_struct *files)
 {
+       if (req->file && req->file->f_op == &io_uring_fops)
+               return true;
+
        return ((req->flags & REQ_F_WORK_INITIALIZED) &&
                (req->work.flags & IO_WQ_WORK_FILES)) &&
                req->work.identity->files == files;
@@ -1398,11 +1401,14 @@ static bool io_grab_identity(struct io_k
                        return false;
                atomic_inc(&id->files->count);
                get_nsproxy(id->nsproxy);
-               req->flags |= REQ_F_INFLIGHT;
 
-               spin_lock_irq(&ctx->inflight_lock);
-               list_add(&req->inflight_entry, &ctx->inflight_list);
-               spin_unlock_irq(&ctx->inflight_lock);
+               if (!(req->flags & REQ_F_INFLIGHT)) {
+                       req->flags |= REQ_F_INFLIGHT;
+
+                       spin_lock_irq(&ctx->inflight_lock);
+                       list_add(&req->inflight_entry, &ctx->inflight_list);
+                       spin_unlock_irq(&ctx->inflight_lock);
+               }
                req->work.flags |= IO_WQ_WORK_FILES;
        }
        if (!(req->work.flags & IO_WQ_WORK_MM) &&
@@ -5886,8 +5892,10 @@ static void io_req_drop_files(struct io_
        struct io_ring_ctx *ctx = req->ctx;
        unsigned long flags;
 
-       put_files_struct(req->work.identity->files);
-       put_nsproxy(req->work.identity->nsproxy);
+       if (req->work.flags & IO_WQ_WORK_FILES) {
+               put_files_struct(req->work.identity->files);
+               put_nsproxy(req->work.identity->nsproxy);
+       }
        spin_lock_irqsave(&ctx->inflight_lock, flags);
        list_del(&req->inflight_entry);
        spin_unlock_irqrestore(&ctx->inflight_lock, flags);
@@ -6159,6 +6167,15 @@ static struct file *io_file_get(struct i
                file = __io_file_get(state, fd);
        }
 
+       if (file && file->f_op == &io_uring_fops) {
+               io_req_init_async(req);
+               req->flags |= REQ_F_INFLIGHT;
+
+               spin_lock_irq(&ctx->inflight_lock);
+               list_add(&req->inflight_entry, &ctx->inflight_list);
+               spin_unlock_irq(&ctx->inflight_lock);
+       }
+
        return file;
 }
 
@@ -8578,8 +8595,7 @@ static void io_uring_cancel_files(struct
 
                spin_lock_irq(&ctx->inflight_lock);
                list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
-                       if (req->task != task ||
-                           req->work.identity->files != files)
+                       if (!io_match_task(req, task, files))
                                continue;
                        found = true;
                        break;