Re: [PATCH for-next v2 21/25] io_uring: add IORING_SETUP_SINGLE_ISSUER

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 6/14/22 22:37, Pavel Begunkov wrote:
Add a new IORING_SETUP_SINGLE_ISSUER flag and the userspace visible part
of it, i.e. put limitations of submitters. Also, don't allow it together
with IOPOLL as we're not going to put it to good use.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
  include/uapi/linux/io_uring.h |  5 ++++-
  io_uring/io_uring.c           |  7 +++++--
  io_uring/io_uring_types.h     |  1 +
  io_uring/tctx.c               | 27 ++++++++++++++++++++++++---
  io_uring/tctx.h               |  4 ++--
  5 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index a41ddb8c5e1f..a3a691340d3e 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -138,9 +138,12 @@ enum {
   * IORING_SQ_TASKRUN in the sq ring flags. Not valid with COOP_TASKRUN.
   */
  #define IORING_SETUP_TASKRUN_FLAG	(1U << 9)
-
  #define IORING_SETUP_SQE128		(1U << 10) /* SQEs are 128 byte */
  #define IORING_SETUP_CQE32		(1U << 11) /* CQEs are 32 byte */
+/*
+ * Only one task is allowed to submit requests
+ */
+#define IORING_SETUP_SINGLE_ISSUER	(1U << 12)
enum io_uring_op {
  	IORING_OP_NOP,
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 15d209f334eb..4b90439808e3 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3020,6 +3020,8 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
  	io_destroy_buffers(ctx);
  	if (ctx->sq_creds)
  		put_cred(ctx->sq_creds);
+	if (ctx->submitter_task)
+		put_task_struct(ctx->submitter_task);
/* there are no registered resources left, nobody uses it */
  	if (ctx->rsrc_node)
@@ -3752,7 +3754,7 @@ static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file)
  	if (fd < 0)
  		return fd;
- ret = io_uring_add_tctx_node(ctx);
+	ret = __io_uring_add_tctx_node(ctx, false);
  	if (ret) {
  		put_unused_fd(fd);
  		return ret;
@@ -3972,7 +3974,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
  			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
  			IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
  			IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
-			IORING_SETUP_SQE128 | IORING_SETUP_CQE32))
+			IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |
+			IORING_SETUP_SINGLE_ISSUER))
  		return -EINVAL;
return io_uring_create(entries, &p, params);
diff --git a/io_uring/io_uring_types.h b/io_uring/io_uring_types.h
index aba0f8cd6f49..f6d0ad25f377 100644
--- a/io_uring/io_uring_types.h
+++ b/io_uring/io_uring_types.h
@@ -241,6 +241,7 @@ struct io_ring_ctx {
  	/* Keep this last, we don't need it for the fast path */
struct io_restriction restrictions;
+	struct task_struct		*submitter_task;
/* slow path rsrc auxilary data, used by update/register */
  	struct io_rsrc_node		*rsrc_backup_node;
diff --git a/io_uring/tctx.c b/io_uring/tctx.c
index 6adf659687f8..012be261dc50 100644
--- a/io_uring/tctx.c
+++ b/io_uring/tctx.c
@@ -81,12 +81,32 @@ __cold int io_uring_alloc_task_context(struct task_struct *task,
  	return 0;
  }
-int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
+static int io_register_submitter(struct io_ring_ctx *ctx)
+{
+	int ret = 0;
+
+	mutex_lock(&ctx->uring_lock);
+	if (!ctx->submitter_task)
+		ctx->submitter_task = get_task_struct(current);
+	else if (ctx->submitter_task != current)
+		ret = -EEXIST;
+	mutex_unlock(&ctx->uring_lock);
+
+	return ret;
+}

Seems we don't need this uring_lock:
When we create a ring, we setup ctx->submitter_task before uring fd is
installed so at that time nobody else can enter this code.
when we enter this code later in io_uring_enter, we just read it.




[Index of Archives]     [Linux Samsung SoC]     [Linux Rockchip SoC]     [Linux Actions SoC]     [Linux for Synopsys ARC Processors]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]


  Powered by Linux