Re: [PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD

Re: [PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD

[kernel test robot]

:::::: 
:::::: Manual check reason: "low confidence static check warning: include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20230307141520.793891-4-ming.lei@redhat.com>
References: <20230307141520.793891-4-ming.lei@redhat.com>
TO: Ming Lei <ming.lei@redhat.com>
TO: Jens Axboe <axboe@kernel.dk>
TO: io-uring@vger.kernel.org
CC: linux-block@vger.kernel.org
CC: Miklos Szeredi <mszeredi@redhat.com>
CC: ZiyangZhang <ZiyangZhang@linux.alibaba.com>
CC: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
CC: Bernd Schubert <bschubert@ddn.com>
CC: Ming Lei <ming.lei@redhat.com>

Hi Ming,

I love your patch! Perhaps something to improve:

[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on char-misc/char-misc-testing char-misc/char-misc-next char-misc/char-misc-linus linus/master v6.3-rc1 next-20230310]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ming-Lei/io_uring-add-IO_URING_F_FUSED-and-prepare-for-supporting-OP_FUSED_CMD/20230307-222928
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20230307141520.793891-4-ming.lei%40redhat.com
patch subject: [PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD
:::::: branch date: 4 days ago
:::::: commit date: 4 days ago
config: microblaze-randconfig-s033-20230308 (https://download.01.org/0day-ci/archive/20230312/202303120203.sqqL7XCB-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 12.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        # https://github.com/intel-lab-lkp/linux/commit/5e0eebd84413d4545e5fc0cc0ede6052cc8df81b
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Ming-Lei/io_uring-add-IO_URING_F_FUSED-and-prepare-for-supporting-OP_FUSED_CMD/20230307-222928
        git checkout 5e0eebd84413d4545e5fc0cc0ede6052cc8df81b
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/r/202303120203.sqqL7XCB-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   kernel/sched/core.c: note: in included file (through kernel/sched/../../io_uring/io-wq.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
   kernel/sched/core.c:7040:17: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/core.c:7040:17: sparse:    struct task_struct *
   kernel/sched/core.c:7040:17: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/core.c:7256:22: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/core.c:7256:22: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/core.c:7256:22: sparse:    struct task_struct *
   kernel/sched/core.c: note: in included file:
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
--
   io_uring/epoll.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/epoll.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/uring_cmd.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/uring_cmd.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/statx.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/statx.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/net.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/net.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/msg_ring.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/msg_ring.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/timeout.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/timeout.c: note: in included file (through include/trace/events/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/sqpoll.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/sqpoll.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/fdinfo.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/fdinfo.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/openclose.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/openclose.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/tctx.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/tctx.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/cancel.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/cancel.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/poll.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/poll.c: note: in included file (through include/trace/events/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/kbuf.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/kbuf.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/rsrc.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/rsrc.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/opdef.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/opdef.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/rw.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/rw.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/io_uring.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/io_uring.c: note: in included file (through include/trace/events/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/nop.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/nop.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/xattr.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/xattr.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/fs.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/fs.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/splice.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/splice.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/notif.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/notif.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/sync.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/sync.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/advise.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/advise.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/filetable.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/filetable.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/fused_cmd.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/fused_cmd.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/io-wq.c: note: in included file:
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/io-wq.c: note: in included file (through io_uring/io-wq.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression

vim +475 include/linux/io_uring_types.h

e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  409  
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  410  enum {
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  411  	/* ctx owns file */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  412  	REQ_F_FIXED_FILE	= BIT(REQ_F_FIXED_FILE_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  413  	/* drain existing IO first */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  414  	REQ_F_IO_DRAIN		= BIT(REQ_F_IO_DRAIN_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  415  	/* linked sqes */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  416  	REQ_F_LINK		= BIT(REQ_F_LINK_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  417  	/* doesn't sever on completion < 0 */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  418  	REQ_F_HARDLINK		= BIT(REQ_F_HARDLINK_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  419  	/* IOSQE_ASYNC */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  420  	REQ_F_FORCE_ASYNC	= BIT(REQ_F_FORCE_ASYNC_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  421  	/* IOSQE_BUFFER_SELECT */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  422  	REQ_F_BUFFER_SELECT	= BIT(REQ_F_BUFFER_SELECT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  423  	/* IOSQE_CQE_SKIP_SUCCESS */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  424  	REQ_F_CQE_SKIP		= BIT(REQ_F_CQE_SKIP_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  425  
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  426  	/* fail rest of links */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  427  	REQ_F_FAIL		= BIT(REQ_F_FAIL_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  428  	/* on inflight list, should be cancelled and waited on exit reliably */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  429  	REQ_F_INFLIGHT		= BIT(REQ_F_INFLIGHT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  430  	/* read/write uses file position */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  431  	REQ_F_CUR_POS		= BIT(REQ_F_CUR_POS_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  432  	/* must not punt to workers */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  433  	REQ_F_NOWAIT		= BIT(REQ_F_NOWAIT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  434  	/* has or had linked timeout */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  435  	REQ_F_LINK_TIMEOUT	= BIT(REQ_F_LINK_TIMEOUT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  436  	/* needs cleanup */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  437  	REQ_F_NEED_CLEANUP	= BIT(REQ_F_NEED_CLEANUP_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  438  	/* already went through poll handler */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  439  	REQ_F_POLLED		= BIT(REQ_F_POLLED_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  440  	/* buffer already selected */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  441  	REQ_F_BUFFER_SELECTED	= BIT(REQ_F_BUFFER_SELECTED_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  442  	/* buffer selected from ring, needs commit */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  443  	REQ_F_BUFFER_RING	= BIT(REQ_F_BUFFER_RING_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  444  	/* caller should reissue async */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  445  	REQ_F_REISSUE		= BIT(REQ_F_REISSUE_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  446  	/* supports async reads/writes */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  447  	REQ_F_SUPPORT_NOWAIT	= BIT(REQ_F_SUPPORT_NOWAIT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  448  	/* regular file */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  449  	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  450  	/* has creds assigned */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  451  	REQ_F_CREDS		= BIT(REQ_F_CREDS_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  452  	/* skip refcounting if not set */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  453  	REQ_F_REFCOUNT		= BIT(REQ_F_REFCOUNT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  454  	/* there is a linked timeout that has to be armed */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  455  	REQ_F_ARM_LTIMEOUT	= BIT(REQ_F_ARM_LTIMEOUT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  456  	/* ->async_data allocated */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  457  	REQ_F_ASYNC_DATA	= BIT(REQ_F_ASYNC_DATA_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  458  	/* don't post CQEs while failing linked requests */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  459  	REQ_F_SKIP_LINK_CQES	= BIT(REQ_F_SKIP_LINK_CQES_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  460  	/* single poll may be active */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  461  	REQ_F_SINGLE_POLL	= BIT(REQ_F_SINGLE_POLL_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  462  	/* double poll may active */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  463  	REQ_F_DOUBLE_POLL	= BIT(REQ_F_DOUBLE_POLL_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  464  	/* request has already done partial IO */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  465  	REQ_F_PARTIAL_IO	= BIT(REQ_F_PARTIAL_IO_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  466  	/* fast poll multishot mode */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  467  	REQ_F_APOLL_MULTISHOT	= BIT(REQ_F_APOLL_MULTISHOT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  468  	/* ->extra1 and ->extra2 are initialised */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  469  	REQ_F_CQE32_INIT	= BIT(REQ_F_CQE32_INIT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  470  	/* recvmsg special flag, clear EPOLLIN */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  471  	REQ_F_CLEAR_POLLIN	= BIT(REQ_F_CLEAR_POLLIN_BIT),
9ca9fb24d5febcc io_uring/io_uring_types.h      Pavel Begunkov 2022-06-16  472  	/* hashed into ->cancel_hash_locked, protected by ->uring_lock */
9ca9fb24d5febcc io_uring/io_uring_types.h      Pavel Begunkov 2022-06-16  473  	REQ_F_HASH_LOCKED	= BIT(REQ_F_HASH_LOCKED_BIT),
5e0eebd84413d45 include/linux/io_uring_types.h Ming Lei       2023-03-07  474  	/* slave request in fused cmd, won't be one uring cmd */
5e0eebd84413d45 include/linux/io_uring_types.h Ming Lei       2023-03-07 @475  	REQ_F_FUSED_SLAVE	= BIT(REQ_F_FUSED_SLAVE_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  476  };
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  477  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Re: [PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD

[kernel test robot]

:::::: 
:::::: Manual check reason: "low confidence static check warning: include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20230307141520.793891-4-ming.lei@redhat.com>
References: <20230307141520.793891-4-ming.lei@redhat.com>
TO: Ming Lei <ming.lei@redhat.com>
TO: Jens Axboe <axboe@kernel.dk>
TO: io-uring@vger.kernel.org
CC: linux-block@vger.kernel.org
CC: Miklos Szeredi <mszeredi@redhat.com>
CC: ZiyangZhang <ZiyangZhang@linux.alibaba.com>
CC: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
CC: Bernd Schubert <bschubert@ddn.com>
CC: Ming Lei <ming.lei@redhat.com>

Hi Ming,

I love your patch! Perhaps something to improve:

[auto build test WARNING on axboe-block/for-next]
[also build test WARNING on char-misc/char-misc-testing char-misc/char-misc-next char-misc/char-misc-linus linus/master v6.3-rc2 next-20230310]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ming-Lei/io_uring-add-IO_URING_F_FUSED-and-prepare-for-supporting-OP_FUSED_CMD/20230307-222928
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
patch link:    https://lore.kernel.org/r/20230307141520.793891-4-ming.lei%40redhat.com
patch subject: [PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD
:::::: branch date: 7 days ago
:::::: commit date: 7 days ago
config: microblaze-randconfig-s033-20230308 (https://download.01.org/0day-ci/archive/20230314/202303141202.PITF2ZKp-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 12.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        # https://github.com/intel-lab-lkp/linux/commit/5e0eebd84413d4545e5fc0cc0ede6052cc8df81b
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Ming-Lei/io_uring-add-IO_URING_F_FUSED-and-prepare-for-supporting-OP_FUSED_CMD/20230307-222928
        git checkout 5e0eebd84413d4545e5fc0cc0ede6052cc8df81b
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/r/202303141202.PITF2ZKp-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   kernel/sched/core.c: note: in included file (through kernel/sched/../../io_uring/io-wq.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
   kernel/sched/core.c:7040:17: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/core.c:7040:17: sparse:    struct task_struct *
   kernel/sched/core.c:7040:17: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/core.c:7256:22: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/core.c:7256:22: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/core.c:7256:22: sparse:    struct task_struct *
   kernel/sched/core.c: note: in included file:
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
   kernel/sched/sched.h:2231:9: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2231:9: sparse:    struct task_struct *
   kernel/sched/sched.h:2073:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct [noderef] __rcu *
   kernel/sched/sched.h:2073:25: sparse:    struct task_struct *
--
   io_uring/rw.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/rw.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/rsrc.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/rsrc.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/opdef.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/opdef.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/notif.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/notif.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/fused_cmd.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/fused_cmd.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/sync.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/sync.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/io-wq.c: note: in included file:
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/io-wq.c: note: in included file (through io_uring/io-wq.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/advise.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/advise.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/filetable.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/filetable.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/openclose.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/openclose.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/uring_cmd.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/uring_cmd.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/epoll.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/epoll.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/statx.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/statx.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/net.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/net.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/timeout.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/timeout.c: note: in included file (through include/trace/events/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/msg_ring.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/msg_ring.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/sqpoll.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/sqpoll.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/tctx.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/tctx.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/fdinfo.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/fdinfo.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/cancel.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/cancel.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/xattr.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/xattr.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/nop.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/nop.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/fs.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/fs.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/poll.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/poll.c: note: in included file (through include/trace/events/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/splice.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/splice.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/io_uring.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/io_uring.c: note: in included file (through include/trace/events/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression
--
   io_uring/kbuf.c: note: in included file (through io_uring/io_uring.h):
   io_uring/slist.h:116:29: sparse: sparse: no newline at end of file
   io_uring/kbuf.c: note: in included file (through io_uring/io_uring.h):
>> include/linux/io_uring_types.h:475:35: sparse: sparse: bad constant expression

vim +475 include/linux/io_uring_types.h

e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  409  
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  410  enum {
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  411  	/* ctx owns file */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  412  	REQ_F_FIXED_FILE	= BIT(REQ_F_FIXED_FILE_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  413  	/* drain existing IO first */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  414  	REQ_F_IO_DRAIN		= BIT(REQ_F_IO_DRAIN_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  415  	/* linked sqes */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  416  	REQ_F_LINK		= BIT(REQ_F_LINK_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  417  	/* doesn't sever on completion < 0 */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  418  	REQ_F_HARDLINK		= BIT(REQ_F_HARDLINK_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  419  	/* IOSQE_ASYNC */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  420  	REQ_F_FORCE_ASYNC	= BIT(REQ_F_FORCE_ASYNC_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  421  	/* IOSQE_BUFFER_SELECT */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  422  	REQ_F_BUFFER_SELECT	= BIT(REQ_F_BUFFER_SELECT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  423  	/* IOSQE_CQE_SKIP_SUCCESS */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  424  	REQ_F_CQE_SKIP		= BIT(REQ_F_CQE_SKIP_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  425  
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  426  	/* fail rest of links */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  427  	REQ_F_FAIL		= BIT(REQ_F_FAIL_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  428  	/* on inflight list, should be cancelled and waited on exit reliably */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  429  	REQ_F_INFLIGHT		= BIT(REQ_F_INFLIGHT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  430  	/* read/write uses file position */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  431  	REQ_F_CUR_POS		= BIT(REQ_F_CUR_POS_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  432  	/* must not punt to workers */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  433  	REQ_F_NOWAIT		= BIT(REQ_F_NOWAIT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  434  	/* has or had linked timeout */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  435  	REQ_F_LINK_TIMEOUT	= BIT(REQ_F_LINK_TIMEOUT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  436  	/* needs cleanup */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  437  	REQ_F_NEED_CLEANUP	= BIT(REQ_F_NEED_CLEANUP_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  438  	/* already went through poll handler */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  439  	REQ_F_POLLED		= BIT(REQ_F_POLLED_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  440  	/* buffer already selected */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  441  	REQ_F_BUFFER_SELECTED	= BIT(REQ_F_BUFFER_SELECTED_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  442  	/* buffer selected from ring, needs commit */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  443  	REQ_F_BUFFER_RING	= BIT(REQ_F_BUFFER_RING_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  444  	/* caller should reissue async */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  445  	REQ_F_REISSUE		= BIT(REQ_F_REISSUE_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  446  	/* supports async reads/writes */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  447  	REQ_F_SUPPORT_NOWAIT	= BIT(REQ_F_SUPPORT_NOWAIT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  448  	/* regular file */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  449  	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  450  	/* has creds assigned */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  451  	REQ_F_CREDS		= BIT(REQ_F_CREDS_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  452  	/* skip refcounting if not set */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  453  	REQ_F_REFCOUNT		= BIT(REQ_F_REFCOUNT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  454  	/* there is a linked timeout that has to be armed */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  455  	REQ_F_ARM_LTIMEOUT	= BIT(REQ_F_ARM_LTIMEOUT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  456  	/* ->async_data allocated */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  457  	REQ_F_ASYNC_DATA	= BIT(REQ_F_ASYNC_DATA_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  458  	/* don't post CQEs while failing linked requests */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  459  	REQ_F_SKIP_LINK_CQES	= BIT(REQ_F_SKIP_LINK_CQES_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  460  	/* single poll may be active */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  461  	REQ_F_SINGLE_POLL	= BIT(REQ_F_SINGLE_POLL_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  462  	/* double poll may active */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  463  	REQ_F_DOUBLE_POLL	= BIT(REQ_F_DOUBLE_POLL_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  464  	/* request has already done partial IO */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  465  	REQ_F_PARTIAL_IO	= BIT(REQ_F_PARTIAL_IO_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  466  	/* fast poll multishot mode */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  467  	REQ_F_APOLL_MULTISHOT	= BIT(REQ_F_APOLL_MULTISHOT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  468  	/* ->extra1 and ->extra2 are initialised */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  469  	REQ_F_CQE32_INIT	= BIT(REQ_F_CQE32_INIT_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  470  	/* recvmsg special flag, clear EPOLLIN */
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  471  	REQ_F_CLEAR_POLLIN	= BIT(REQ_F_CLEAR_POLLIN_BIT),
9ca9fb24d5febcc io_uring/io_uring_types.h      Pavel Begunkov 2022-06-16  472  	/* hashed into ->cancel_hash_locked, protected by ->uring_lock */
9ca9fb24d5febcc io_uring/io_uring_types.h      Pavel Begunkov 2022-06-16  473  	REQ_F_HASH_LOCKED	= BIT(REQ_F_HASH_LOCKED_BIT),
5e0eebd84413d45 include/linux/io_uring_types.h Ming Lei       2023-03-07  474  	/* slave request in fused cmd, won't be one uring cmd */
5e0eebd84413d45 include/linux/io_uring_types.h Ming Lei       2023-03-07 @475  	REQ_F_FUSED_SLAVE	= BIT(REQ_F_FUSED_SLAVE_BIT),
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  476  };
e27f928ee1cb068 io_uring/io_uring_types.h      Jens Axboe     2022-05-24  477  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

[PATCH V2 00/17] io_uring/ublk: add IORING_OP_FUSED_CMD

[Ming Lei]

Hello,

Add IORING_OP_FUSED_CMD, it is one special URING_CMD, which has to
be SQE128. The 1st SQE(master) is one 64byte URING_CMD, and the 2nd
64byte SQE(slave) is another normal 64byte OP. For any OP which needs
to support slave OP, io_issue_defs[op].fused_slave needs to be set as 1,
and its ->issue() can retrieve/import buffer from master request's
fused_cmd_kbuf. The slave OP is actually submitted from kernel, part of
this idea is from Xiaoguang's ublk ebpf patchset, but this patchset
submits slave OP just like normal OP issued from userspace, that said,
SQE order is kept, and batching handling is done too.

Please see detailed design in commit log of the 3th patch, and one big
point is how to handle buffer ownership.

With this way, it is easy to support zero copy for ublk/fuse device.

Basically userspace can specify any sub-buffer of the ublk block request
buffer from the fused command just by setting 'offset/len'
in the slave SQE for running slave OP. This way is flexible to implement
io mapping: mirror, stripped, ...

The 4th & 5th patches enable fused slave support for the following OPs:

	OP_READ/OP_WRITE
	OP_SEND/OP_RECV/OP_SEND_ZC

The other ublk patches cleans ublk driver and implement fused command
for supporting zero copy.

Follows userspace code:

https://github.com/ming1/ubdsrv/tree/fused-cmd-zc-v2

All three(loop, nbd and qcow2) ublk targets have supported zero copy by passing:

	ublk add -t [loop|nbd|qcow2] -z .... 

Basic fs mount/kernel building and builtin test are done.

Also add liburing test case for covering fused command based on miniublk
of blktest:

https://github.com/ming1/liburing/commits/fused_cmd_miniublk

Performance improvement is obvious on memory bandwidth
related workloads, such as, 1~2X improvement on 64K/512K BS
IO test on loop with ramfs backing file.

Any comments are welcome!

V2:
	- don't resue io_mapped_ubuf (io_uring)
	- remove REQ_F_FUSED_MASTER_BIT (io_uring)
	- fix compile warning (io_uring)
	- rebase on v6.3-rc1 (io_uring)
	- grabbing io request reference when handling fused command 
	- simplify ublk_copy_user_pages() by iov iterator
	- add read()/write() for userspace to read/write ublk io buffer, so
	that some corner cases(read zero, passthrough request(report zones)) can
	be handled easily in case of zero copy; this way also helps to switch to
	zero copy completely
	- misc cleanup

Ming Lei (17):
  io_uring: add IO_URING_F_FUSED and prepare for supporting OP_FUSED_CMD
  io_uring: increase io_kiocb->flags into 64bit
  io_uring: add IORING_OP_FUSED_CMD
  io_uring: support OP_READ/OP_WRITE for fused slave request
  io_uring: support OP_SEND_ZC/OP_RECV for fused slave request
  block: ublk_drv: mark device as LIVE before adding disk
  block: ublk_drv: add common exit handling
  block: ublk_drv: don't consider flush request in map/unmap io
  block: ublk_drv: add two helpers to clean up map/unmap request
  block: ublk_drv: clean up several helpers
  block: ublk_drv: cleanup 'struct ublk_map_data'
  block: ublk_drv: cleanup ublk_copy_user_pages
  block: ublk_drv: grab request reference when the request is handled by
    userspace
  block: ublk_drv: support to copy any part of request pages
  block: ublk_drv: add read()/write() support for ublk char device
  block: ublk_drv: don't check buffer in case of zero copy
  block: ublk_drv: apply io_uring FUSED_CMD for supporting zero copy

 drivers/block/ublk_drv.c       | 605 ++++++++++++++++++++++++++-------
 drivers/char/mem.c             |   4 +
 drivers/nvme/host/ioctl.c      |   9 +
 include/linux/io_uring.h       |  49 ++-
 include/linux/io_uring_types.h |  18 +-
 include/uapi/linux/io_uring.h  |   1 +
 include/uapi/linux/ublk_cmd.h  |  37 +-
 io_uring/Makefile              |   2 +-
 io_uring/fused_cmd.c           | 232 +++++++++++++
 io_uring/fused_cmd.h           |  11 +
 io_uring/io_uring.c            |  22 +-
 io_uring/io_uring.h            |   3 +
 io_uring/net.c                 |  23 +-
 io_uring/opdef.c               |  17 +
 io_uring/opdef.h               |   2 +
 io_uring/rw.c                  |  20 ++
 16 files changed, 926 insertions(+), 129 deletions(-)
 create mode 100644 io_uring/fused_cmd.c
 create mode 100644 io_uring/fused_cmd.h

-- 
2.39.2

[PATCH V2 03/17] io_uring: add IORING_OP_FUSED_CMD

[Ming Lei]

Add IORING_OP_FUSED_CMD, it is one special URING_CMD, which has to
be SQE128. The 1st SQE(master) is one 64byte URING_CMD, and the 2nd
64byte SQE(slave) is another normal 64byte OP. For any OP which needs
to support slave OP, io_issue_defs[op].fused_slave has to be set as 1,
and its ->issue() needs to retrieve buffer from master request's
fused_cmd_kbuf.

Follows the key points of the design/implementation:

1) The master uring command produces and provides immutable command
buffer(struct io_uring_bvec_buf) to the slave request, and the slave
OP can retrieve any part of this buffer by sqe->addr and sqe->len.

2) Master command is always completed after the slave request is
completed.

- Before slave request is submitted, the buffer ownership is
transferred to slave request. After slave request is completed,
the buffer ownership is returned back to master request.

- This way also guarantees correct SQE order since the master
request uses slave request's LINK flag.

3) Master request is always completed by driver, so that driver
can know when the buffer is done with slave quest.

The motivation is for supporting zero copy for fuse/ublk, in which
the device holds IO request buffer, and IO handling is often normal
IO OP(fs, net, ..). With IORING_OP_FUSED_CMD, we can implement this kind
of zero copy easily & reliably.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 include/linux/io_uring.h       |  42 +++++-
 include/linux/io_uring_types.h |  15 +++
 include/uapi/linux/io_uring.h  |   1 +
 io_uring/Makefile              |   2 +-
 io_uring/fused_cmd.c           | 232 +++++++++++++++++++++++++++++++++
 io_uring/fused_cmd.h           |  11 ++
 io_uring/io_uring.c            |  20 ++-
 io_uring/io_uring.h            |   3 +
 io_uring/opdef.c               |  12 ++
 io_uring/opdef.h               |   2 +
 10 files changed, 334 insertions(+), 6 deletions(-)
 create mode 100644 io_uring/fused_cmd.c
 create mode 100644 io_uring/fused_cmd.h

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 0676c5b4b5fe..f3a23e00b47c 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -4,6 +4,7 @@
 
 #include <linux/sched.h>
 #include <linux/xarray.h>
+#include <linux/bvec.h>
 #include <uapi/linux/io_uring.h>
 
 enum io_uring_cmd_flags {
@@ -29,6 +30,19 @@ enum io_uring_cmd_flags {
 		IO_URING_F_FUSED_READ,
 };
 
+union io_uring_fused_cmd_data {
+	/*
+	 * In case of slave request IOSQE_CQE_SKIP_SUCCESS, return slave
+	 * result via master command; otherwise we simply return success
+	 * if buffer is provided, and slave request will return its result
+	 * via its CQE
+	 */
+	s32 slave_res;
+
+	/* fused cmd private, driver do not touch it */
+	struct io_kiocb *__slave;
+};
+
 struct io_uring_cmd {
 	struct file	*file;
 	const void	*cmd;
@@ -40,10 +54,31 @@ struct io_uring_cmd {
 	};
 	u32		cmd_op;
 	u32		flags;
-	u8		pdu[32]; /* available inline for free use */
+
+	/* for fused command, the available pdu is a bit less */
+	union {
+		struct {
+			union io_uring_fused_cmd_data data;
+			u8	pdu[24]; /* available inline for free use */
+		} fused;
+		u8		pdu[32]; /* available inline for free use */
+	};
+};
+
+struct io_uring_bvec_buf {
+	unsigned long	len;
+	unsigned int	nr_bvecs;
+
+	/* offset in the 1st bvec */
+	unsigned int	offset;
+	struct bio_vec	*bvec;
+	struct bio_vec	__bvec[];
 };
 
 #if defined(CONFIG_IO_URING)
+void io_fused_cmd_provide_kbuf(struct io_uring_cmd *ioucmd, bool locked,
+		const struct io_uring_bvec_buf *imu,
+		void (*complete_tw_cb)(struct io_uring_cmd *));
 int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 			      struct iov_iter *iter, void *ioucmd);
 void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret, ssize_t res2);
@@ -73,6 +108,11 @@ static inline void io_uring_free(struct task_struct *tsk)
 		__io_uring_free(tsk);
 }
 #else
+static inline void io_fused_cmd_provide_kbuf(struct io_uring_cmd *ioucmd,
+		bool locked, const struct io_uring_bvec_buf *fused_cmd_kbuf,
+		unsigned int len, void (*complete_tw_cb)(struct io_uring_cmd *))
+{
+}
 static inline int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
 			      struct iov_iter *iter, void *ioucmd)
 {
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 66fd0f7f1b24..088df87f6e8c 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -401,6 +401,7 @@ enum {
 	/* keep async read/write and isreg together and in order */
 	REQ_F_SUPPORT_NOWAIT_BIT,
 	REQ_F_ISREG_BIT,
+	REQ_F_FUSED_SLAVE_BIT,
 
 	/* not a real bit, just to check we're not overflowing the space */
 	__REQ_F_LAST_BIT,
@@ -470,6 +471,8 @@ enum {
 	REQ_F_CLEAR_POLLIN	= BIT(REQ_F_CLEAR_POLLIN_BIT),
 	/* hashed into ->cancel_hash_locked, protected by ->uring_lock */
 	REQ_F_HASH_LOCKED	= BIT(REQ_F_HASH_LOCKED_BIT),
+	/* slave request in fused cmd, won't be one uring cmd */
+	REQ_F_FUSED_SLAVE	= BIT(REQ_F_FUSED_SLAVE_BIT),
 };
 
 typedef void (*io_req_tw_func_t)(struct io_kiocb *req, bool *locked);
@@ -552,6 +555,18 @@ struct io_kiocb {
 		 * REQ_F_BUFFER_RING is set.
 		 */
 		struct io_buffer_list	*buf_list;
+
+		/*
+		 * store kernel (sub)buffer of fused master request which OP
+		 * is IORING_OP_FUSED_CMD
+		 */
+		const struct io_uring_bvec_buf *fused_cmd_kbuf;
+
+		/*
+		 * store fused command master request for fuse slave request,
+		 * which uses fuse master's kernel buffer for handling this OP
+		 */
+		struct io_kiocb *fused_master_req;
 	};
 
 	union {
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 709de6d4feb2..f07d005ee898 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -223,6 +223,7 @@ enum io_uring_op {
 	IORING_OP_URING_CMD,
 	IORING_OP_SEND_ZC,
 	IORING_OP_SENDMSG_ZC,
+	IORING_OP_FUSED_CMD,
 
 	/* this goes last, obviously */
 	IORING_OP_LAST,
diff --git a/io_uring/Makefile b/io_uring/Makefile
index 8cc8e5387a75..5301077e61c5 100644
--- a/io_uring/Makefile
+++ b/io_uring/Makefile
@@ -7,5 +7,5 @@ obj-$(CONFIG_IO_URING)		+= io_uring.o xattr.o nop.o fs.o splice.o \
 					openclose.o uring_cmd.o epoll.o \
 					statx.o net.o msg_ring.o timeout.o \
 					sqpoll.o fdinfo.o tctx.o poll.o \
-					cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o
+					cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o fused_cmd.o
 obj-$(CONFIG_IO_WQ)		+= io-wq.o
diff --git a/io_uring/fused_cmd.c b/io_uring/fused_cmd.c
new file mode 100644
index 000000000000..9435e67fc47c
--- /dev/null
+++ b/io_uring/fused_cmd.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/io_uring.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "opdef.h"
+#include "rsrc.h"
+#include "uring_cmd.h"
+#include "fused_cmd.h"
+
+static bool io_fused_slave_valid(const struct io_uring_sqe *sqe, u8 op)
+{
+	unsigned int sqe_flags = READ_ONCE(sqe->flags);
+
+	if (op == IORING_OP_FUSED_CMD || op == IORING_OP_URING_CMD)
+		return false;
+
+	if (sqe_flags & REQ_F_BUFFER_SELECT)
+		return false;
+
+	if (!io_issue_defs[op].fused_slave)
+		return false;
+
+	return true;
+}
+
+static inline void io_fused_cmd_update_link_flags(struct io_kiocb *req,
+		const struct io_kiocb *slave)
+{
+	/*
+	 * We have to keep slave SQE in order, so update master link flags
+	 * with slave request's given master command isn't completed until
+	 * the slave request is done
+	 */
+	if (slave->flags & (REQ_F_LINK | REQ_F_HARDLINK))
+		req->flags |= REQ_F_LINK;
+}
+
+int io_fused_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
+	__must_hold(&req->ctx->uring_lock)
+{
+	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	const struct io_uring_sqe *slave_sqe = sqe + 1;
+	struct io_ring_ctx *ctx = req->ctx;
+	struct io_kiocb *slave;
+	u8 slave_op;
+	int ret;
+
+	if (unlikely(!(ctx->flags & IORING_SETUP_SQE128)))
+		return -EINVAL;
+
+	if (unlikely(sqe->__pad1))
+		return -EINVAL;
+
+	ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);
+	if (unlikely(ioucmd->flags))
+		return -EINVAL;
+
+	slave_op = READ_ONCE(slave_sqe->opcode);
+	if (unlikely(!io_fused_slave_valid(slave_sqe, slave_op)))
+		return -EINVAL;
+
+	ioucmd->cmd = sqe->cmd;
+	ioucmd->cmd_op = READ_ONCE(sqe->cmd_op);
+	req->fused_cmd_kbuf = NULL;
+
+	/* take one extra reference for the slave request */
+	io_get_task_refs(1);
+
+	ret = -ENOMEM;
+	if (unlikely(!io_alloc_req(ctx, &slave)))
+		goto fail;
+
+	ret = io_init_req(ctx, slave, slave_sqe, true);
+	if (unlikely(ret))
+		goto fail_free_req;
+
+	io_fused_cmd_update_link_flags(req, slave);
+
+	ioucmd->fused.data.__slave = slave;
+
+	return 0;
+
+fail_free_req:
+	io_free_req(slave);
+fail:
+	current->io_uring->cached_refs += 1;
+	return ret;
+}
+
+static inline bool io_fused_slave_write_to_buf(u8 op)
+{
+	switch (op) {
+	case IORING_OP_READ:
+	case IORING_OP_READV:
+	case IORING_OP_READ_FIXED:
+	case IORING_OP_RECVMSG:
+	case IORING_OP_RECV:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+int io_fused_cmd(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	const struct io_kiocb *slave = ioucmd->fused.data.__slave;
+	int ret = -EINVAL;
+
+	/*
+	 * Pass buffer direction for driver to validate if the read/write
+	 * is legal
+	 */
+	if (io_fused_slave_write_to_buf(slave->opcode))
+		issue_flags |= IO_URING_F_FUSED_WRITE;
+	else
+		issue_flags |= IO_URING_F_FUSED_READ;
+
+	ret = io_uring_cmd(req, issue_flags);
+	if (ret != IOU_ISSUE_SKIP_COMPLETE)
+		io_free_req(ioucmd->fused.data.__slave);
+
+	return ret;
+}
+
+int io_import_kbuf_for_slave(unsigned long buf_off, unsigned int len, int dir,
+		struct iov_iter *iter, struct io_kiocb *slave)
+{
+	struct io_kiocb *req = slave->fused_master_req;
+	const struct io_uring_bvec_buf *kbuf;
+	unsigned long offset;
+
+	if (unlikely(!(slave->flags & REQ_F_FUSED_SLAVE) || !req))
+		return -EINVAL;
+
+	if (unlikely(!req->fused_cmd_kbuf))
+		return -EINVAL;
+
+	/* req->fused_cmd_kbuf is immutable */
+	kbuf = req->fused_cmd_kbuf;
+	offset = kbuf->offset;
+
+	if (!kbuf->bvec)
+		return -EINVAL;
+
+	if (unlikely(buf_off > kbuf->len))
+		return -EFAULT;
+
+	if (unlikely(len > kbuf->len - buf_off))
+		return -EFAULT;
+
+	/* don't use io_import_fixed which doesn't support multipage bvec */
+	offset += buf_off;
+	iov_iter_bvec(iter, dir, kbuf->bvec, kbuf->nr_bvecs, offset + len);
+
+	if (offset)
+		iov_iter_advance(iter, offset);
+
+	return 0;
+}
+
+/*
+ * Called when slave request is completed,
+ *
+ * Return back ownership of the fused_cmd kbuf to master request, and
+ * notify master request.
+ */
+void io_fused_cmd_return_kbuf(struct io_kiocb *slave)
+{
+	struct io_kiocb *req = slave->fused_master_req;
+	struct io_uring_cmd *ioucmd;
+
+	if (unlikely(!req || !(slave->flags & REQ_F_FUSED_SLAVE)))
+		return;
+
+	/* return back the buffer */
+	slave->fused_master_req = NULL;
+	ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd);
+	ioucmd->fused.data.__slave = NULL;
+
+	/* If slave OP skips CQE, return the result via master command */
+	if (slave->flags & REQ_F_CQE_SKIP)
+		ioucmd->fused.data.slave_res = slave->cqe.res;
+	else
+		ioucmd->fused.data.slave_res = 0;
+	io_uring_cmd_complete_in_task(ioucmd, ioucmd->task_work_cb);
+}
+
+/*
+ * This API needs to be called when master command has prepared
+ * FUSED_CMD buffer, and offset/len in ->fused.data is for retrieving
+ * sub-buffer in the command buffer, which is often figured out by
+ * command payload data.
+ *
+ * Master command is always completed after the slave request
+ * is completed, so driver has to set completion callback for
+ * getting notification.
+ *
+ * Ownership of the fused_cmd kbuf is transferred to slave request.
+ */
+void io_fused_cmd_provide_kbuf(struct io_uring_cmd *ioucmd, bool locked,
+		const struct io_uring_bvec_buf *fused_cmd_kbuf,
+		void (*complete_tw_cb)(struct io_uring_cmd *))
+{
+	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
+	struct io_kiocb *slave = ioucmd->fused.data.__slave;
+
+	/*
+	 * Once the fused slave request is completed, the driver will
+	 * be notified by callback of complete_tw_cb
+	 */
+	ioucmd->task_work_cb = complete_tw_cb;
+
+	/* now we get the buffer */
+	req->fused_cmd_kbuf = fused_cmd_kbuf;
+	slave->fused_master_req = req;
+
+	trace_io_uring_submit_sqe(slave, true);
+	if (locked)
+		io_req_task_submit(slave, &locked);
+	else
+		io_req_task_queue(slave);
+}
+EXPORT_SYMBOL_GPL(io_fused_cmd_provide_kbuf);
diff --git a/io_uring/fused_cmd.h b/io_uring/fused_cmd.h
new file mode 100644
index 000000000000..86ad87d1b0ec
--- /dev/null
+++ b/io_uring/fused_cmd.h
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_FUSED_CMD_H
+#define IOU_FUSED_CMD_H
+
+int io_fused_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
+int io_fused_cmd(struct io_kiocb *req, unsigned int issue_flags);
+void io_fused_cmd_return_kbuf(struct io_kiocb *slave);
+int io_import_kbuf_for_slave(unsigned long buf, unsigned int len, int dir,
+		struct iov_iter *iter, struct io_kiocb *slave);
+
+#endif
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 90a835215d04..46c060713928 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -91,6 +91,7 @@
 #include "cancel.h"
 #include "net.h"
 #include "notif.h"
+#include "fused_cmd.h"
 
 #include "timeout.h"
 #include "poll.h"
@@ -110,7 +111,7 @@
 
 #define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
 				REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
-				REQ_F_ASYNC_DATA)
+				REQ_F_ASYNC_DATA | REQ_F_FUSED_SLAVE)
 
 #define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
 				 IO_REQ_CLEAN_FLAGS)
@@ -964,6 +965,9 @@ static void __io_req_complete_post(struct io_kiocb *req)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 
+	if (req->flags & REQ_F_FUSED_SLAVE)
+		io_fused_cmd_return_kbuf(req);
+
 	io_cq_lock(ctx);
 	if (!(req->flags & REQ_F_CQE_SKIP))
 		io_fill_cqe_req(ctx, req);
@@ -1848,6 +1852,8 @@ static void io_clean_op(struct io_kiocb *req)
 		spin_lock(&req->ctx->completion_lock);
 		io_put_kbuf_comp(req);
 		spin_unlock(&req->ctx->completion_lock);
+	} else if (req->flags & REQ_F_FUSED_SLAVE) {
+		io_fused_cmd_return_kbuf(req);
 	}
 
 	if (req->flags & REQ_F_NEED_CLEANUP) {
@@ -2156,8 +2162,8 @@ static void io_init_req_drain(struct io_kiocb *req)
 	}
 }
 
-static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
-		       const struct io_uring_sqe *sqe)
+int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
+		const struct io_uring_sqe *sqe, bool slave)
 	__must_hold(&ctx->uring_lock)
 {
 	const struct io_issue_def *def;
@@ -2210,6 +2216,12 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 		}
 	}
 
+	if (slave) {
+		if (!def->fused_slave)
+		       return -EINVAL;
+		req->flags |= REQ_F_FUSED_SLAVE;
+	}
+
 	if (!def->ioprio && sqe->ioprio)
 		return -EINVAL;
 	if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
@@ -2294,7 +2306,7 @@ static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	struct io_submit_link *link = &ctx->submit_state.link;
 	int ret;
 
-	ret = io_init_req(ctx, req, sqe);
+	ret = io_init_req(ctx, req, sqe, false);
 	if (unlikely(ret))
 		return io_submit_fail_init(sqe, req, ret);
 
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 2711865f1e19..a50c7e1f6e81 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -78,6 +78,9 @@ bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
 			bool cancel_all);
 
+int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
+		const struct io_uring_sqe *sqe, bool slave);
+
 #define io_lockdep_assert_cq_locked(ctx)				\
 	do {								\
 		if (ctx->flags & IORING_SETUP_IOPOLL) {			\
diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index cca7c5b55208..63b90e8e65f8 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -33,6 +33,7 @@
 #include "poll.h"
 #include "cancel.h"
 #include "rw.h"
+#include "fused_cmd.h"
 
 static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags)
 {
@@ -428,6 +429,12 @@ const struct io_issue_def io_issue_defs[] = {
 		.prep			= io_eopnotsupp_prep,
 #endif
 	},
+	[IORING_OP_FUSED_CMD] = {
+		.needs_file		= 1,
+		.plug			= 1,
+		.prep			= io_fused_cmd_prep,
+		.issue			= io_fused_cmd,
+	},
 };
 
 
@@ -648,6 +655,11 @@ const struct io_cold_def io_cold_defs[] = {
 		.fail			= io_sendrecv_fail,
 #endif
 	},
+	[IORING_OP_FUSED_CMD] = {
+		.name			= "FUSED_CMD",
+		.async_size		= uring_cmd_pdu_size(1),
+		.prep_async		= io_uring_cmd_prep_async,
+	},
 };
 
 const char *io_uring_get_opcode(u8 opcode)
diff --git a/io_uring/opdef.h b/io_uring/opdef.h
index c22c8696e749..306f6fc48ed4 100644
--- a/io_uring/opdef.h
+++ b/io_uring/opdef.h
@@ -29,6 +29,8 @@ struct io_issue_def {
 	unsigned		iopoll_queue : 1;
 	/* opcode specific path will handle ->async_data allocation if needed */
 	unsigned		manual_alloc : 1;
+	/* can be slave op of fused command */
+	unsigned		fused_slave : 1;
 
 	int (*issue)(struct io_kiocb *, unsigned int);
 	int (*prep)(struct io_kiocb *, const struct io_uring_sqe *);
-- 
2.39.2