io_uring/tctx: have io_uring_alloc_task_context() return tctx

Instead of having io_uring_alloc_task_context() return an int and
assign tsk->io_uring, just have it return the task context directly.
This enables cleaner error handling in callers, which may have
failure points post calling io_uring_alloc_task_context().

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index c6bb938ec5ea4d879d5b02b1390cce26d151cf69..46c12afec73ec57ddc60f9b98e723c9e8d74e05a 100644 (file)
--- a/io_uring/sqpoll.c
+++ b/io_uring/sqpoll.c
@@ -458,6 +458,7 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
                        return -EINVAL;
        }
        if (ctx->flags & IORING_SETUP_SQPOLL) {
+               struct io_uring_task *tctx;
                struct task_struct *tsk;
                struct io_sq_data *sqd;
                bool attached;
@@ -524,8 +525,13 @@ __cold int io_sq_offload_create(struct io_ring_ctx *ctx,
                rcu_assign_pointer(sqd->thread, tsk);
                mutex_unlock(&sqd->lock);
 
+               ret = 0;
                get_task_struct(tsk);
-               ret = io_uring_alloc_task_context(tsk, ctx);
+               tctx = io_uring_alloc_task_context(tsk, ctx);
+               if (!IS_ERR(tctx))
+                       tsk->io_uring = tctx;
+               else
+                       ret = PTR_ERR(tctx);
                wake_up_new_task(tsk);
                if (ret)
                        goto err;

diff --git a/io_uring/tctx.c b/io_uring/tctx.c
index 143de8e990eb3a586e9a61129ad91ff9e6c038b9..e5cef6a8dde004faf372180ee86d1cbfb4d6ddce 100644 (file)
--- a/io_uring/tctx.c
+++ b/io_uring/tctx.c
@@ -74,20 +74,20 @@ void __io_uring_free(struct task_struct *tsk)
        }
 }
 
-__cold int io_uring_alloc_task_context(struct task_struct *task,
-                                      struct io_ring_ctx *ctx)
+__cold struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task,
+                                                       struct io_ring_ctx *ctx)
 {
        struct io_uring_task *tctx;
        int ret;
 
        tctx = kzalloc_obj(*tctx);
        if (unlikely(!tctx))
-               return -ENOMEM;
+               return ERR_PTR(-ENOMEM);
 
        ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
        if (unlikely(ret)) {
                kfree(tctx);
-               return ret;
+               return ERR_PTR(ret);
        }
 
        tctx->io_wq = io_init_wq_offload(ctx, task);
@@ -95,7 +95,7 @@ __cold int io_uring_alloc_task_context(struct task_struct *task,
                ret = PTR_ERR(tctx->io_wq);
                percpu_counter_destroy(&tctx->inflight);
                kfree(tctx);
-               return ret;
+               return ERR_PTR(ret);
        }
 
        tctx->task = task;
@@ -103,10 +103,9 @@ __cold int io_uring_alloc_task_context(struct task_struct *task,
        init_waitqueue_head(&tctx->wait);
        atomic_set(&tctx->in_cancel, 0);
        atomic_set(&tctx->inflight_tracked, 0);
-       task->io_uring = tctx;
        init_llist_head(&tctx->task_list);
        init_task_work(&tctx->task_work, tctx_task_work);
-       return 0;
+       return tctx;
 }
 
 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
@@ -116,11 +115,11 @@ int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
        int ret;
 
        if (unlikely(!tctx)) {
-               ret = io_uring_alloc_task_context(current, ctx);
-               if (unlikely(ret))
-                       return ret;
+               tctx = io_uring_alloc_task_context(current, ctx);
+               if (IS_ERR(tctx))
+                       return PTR_ERR(tctx);
 
-               tctx = current->io_uring;
+               current->io_uring = tctx;
                if (ctx->int_flags & IO_RING_F_IOWQ_LIMITS_SET) {
                        unsigned int limits[2] = { ctx->iowq_limits[0],
                                                   ctx->iowq_limits[1], };

diff --git a/io_uring/tctx.h b/io_uring/tctx.h
index 608e96de70a2c6f8fec3e644733daf4a09742e21..2310d2a0c46d9ff406ae3ca3d7f6cbf243a5e485 100644 (file)
--- a/io_uring/tctx.h
+++ b/io_uring/tctx.h
@@ -6,8 +6,8 @@ struct io_tctx_node {
        struct io_ring_ctx      *ctx;
 };
 
-int io_uring_alloc_task_context(struct task_struct *task,
-                               struct io_ring_ctx *ctx);
+struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task,
+                                                 struct io_ring_ctx *ctx);
 void io_uring_del_tctx_node(unsigned long index);
 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx);
 int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx);