Merge tag 'for-5.13/io_uring-2021-04-27' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:

 - Support for multi-shot mode for POLL requests

 - More efficient reference counting. This is shamelessly stolen from
   the mm side. Even though referencing is mostly single/dual user, the
   128 count was retained to keep the code the same. Maybe this
   should/could be made generic at some point.

 - Removal of the need to have a manager thread for each ring. The
   manager threads only job was checking and creating new io-threads as
   needed, instead we handle this from the queue path.

 - Allow SQPOLL without CAP_SYS_ADMIN or CAP_SYS_NICE. Since 5.12, this
   thread is "just" a regular application thread, so no need to restrict
   use of it anymore.

 - Cleanup of how internal async poll data lifetime is managed.

 - Fix for syzbot reported crash on SQPOLL cancelation.

 - Make buffer registration more like file registrations, which includes
   flexibility in avoiding full set unregistration and re-registration.

 - Fix for io-wq affinity setting.

 - Be a bit more defensive in task->pf_io_worker setup.

 - Various SQPOLL fixes.

 - Cleanup of SQPOLL creds handling.

 - Improvements to in-flight request tracking.

 - File registration cleanups.

 - Tons of cleanups and little fixes

* tag 'for-5.13/io_uring-2021-04-27' of git://git.kernel.dk/linux-block: (156 commits)
  io_uring: maintain drain logic for multishot poll requests
  io_uring: Check current->io_uring in io_uring_cancel_sqpoll
  io_uring: fix NULL reg-buffer
  io_uring: simplify SQPOLL cancellations
  io_uring: fix work_exit sqpoll cancellations
  io_uring: Fix uninitialized variable up.resv
  io_uring: fix invalid error check after malloc
  io_uring: io_sq_thread() no longer needs to reset current->pf_io_worker
  kernel: always initialize task->pf_io_worker to NULL
  io_uring: update sq_thread_idle after ctx deleted
  io_uring: add full-fledged dynamic buffers support
  io_uring: implement fixed buffers registration similar to fixed files
  io_uring: prepare fixed rw for dynanic buffers
  io_uring: keep table of pointers to ubufs
  io_uring: add generic rsrc update with tags
  io_uring: add IORING_REGISTER_RSRC
  io_uring: enumerate dynamic resources
  io_uring: add generic path for rsrc update
  io_uring: preparation for rsrc tagging
  io_uring: decouple CQE filling from requests
  ...

include/uapi/linux/io_uring.h

@@ -159,6 +159,21 @@ enum {
  */
 #define SPLICE_F_FD_IN_FIXED	(1U << 31) /* the last bit of __u32 */
 
+/*
+ * POLL_ADD flags. Note that since sqe->poll_events is the flag space, the
+ * command flags for POLL_ADD are stored in sqe->len.
+ *
+ * IORING_POLL_ADD_MULTI	Multishot poll. Sets IORING_CQE_F_MORE if
+ *				the poll handler will continue to report
+ *				CQEs on behalf of the same SQE.
+ *
+ * IORING_POLL_UPDATE		Update existing poll request, matching
+ *				sqe->addr as the old user_data field.
+ */
+#define IORING_POLL_ADD_MULTI	(1U << 0)
+#define IORING_POLL_UPDATE_EVENTS	(1U << 1)
+#define IORING_POLL_UPDATE_USER_DATA	(1U << 2)
+
 /*
  * IO completion data structure (Completion Queue Entry)
  */
@@ -172,8 +187,10 @@ struct io_uring_cqe {
  * cqe->flags
  *
  * IORING_CQE_F_BUFFER	If set, the upper 16 bits are the buffer ID
+ * IORING_CQE_F_MORE	If set, parent SQE will generate more CQE entries
  */
 #define IORING_CQE_F_BUFFER		(1U << 0)
+#define IORING_CQE_F_MORE		(1U << 1)
 
 enum {
 	IORING_CQE_BUFFER_SHIFT		= 16,
@@ -281,6 +298,8 @@ enum {
 	IORING_UNREGISTER_PERSONALITY		= 10,
 	IORING_REGISTER_RESTRICTIONS		= 11,
 	IORING_REGISTER_ENABLE_RINGS		= 12,
+	IORING_REGISTER_RSRC			= 13,
+	IORING_REGISTER_RSRC_UPDATE		= 14,
 
 	/* this goes last */
 	IORING_REGISTER_LAST
@@ -293,12 +312,33 @@ struct io_uring_files_update {
 	__aligned_u64 /* __s32 * */ fds;
 };
 
+enum {
+	IORING_RSRC_FILE		= 0,
+	IORING_RSRC_BUFFER		= 1,
+};
+
+struct io_uring_rsrc_register {
+	__u32 type;
+	__u32 nr;
+	__aligned_u64 data;
+	__aligned_u64 tags;
+};
+
 struct io_uring_rsrc_update {
 	__u32 offset;
 	__u32 resv;
 	__aligned_u64 data;
 };
 
+struct io_uring_rsrc_update2 {
+	__u32 offset;
+	__u32 resv;
+	__aligned_u64 data;
+	__aligned_u64 tags;
+	__u32 type;
+	__u32 nr;
+};
+
 /* Skip updating fd indexes set to this value in the fd table */
 #define IORING_REGISTER_FILES_SKIP	(-2)