[PATCH v2] io_uring: Add support for napi_busy_poll

[PATCH v2] io_uring: Add support for napi_busy_poll

[Olivier Langlois]

The sqpoll thread can be used for performing the napi busy poll in a
similar way that it does io polling for file systems supporting direct
access bypassing the page cache.

The other way that io_uring can be used for napi busy poll is by
calling io_uring_enter() to get events.

If the user specify a timeout value, it is distributed between polling
and sleeping by using the systemwide setting
/proc/sys/net/core/busy_poll.

The changes have been tested with this program:
https://github.com/lano1106/io_uring_udp_ping

and the result is:
Without sqpoll:
NAPI busy loop disabled:
rtt min/avg/max/mdev = 40.631/42.050/58.667/1.547 us
NAPI busy loop enabled:
rtt min/avg/max/mdev = 30.619/31.753/61.433/1.456 us

With sqpoll:
NAPI busy loop disabled:
rtt min/avg/max/mdev = 42.087/44.438/59.508/1.533 us
NAPI busy loop enabled:
rtt min/avg/max/mdev = 35.779/37.347/52.201/0.924 us

v2:
 * Evaluate list_empty(&ctx->napi_list) outside io_napi_busy_loop() to keep
   __io_sq_thread() execution as fast as possible
 * In io_cqring_wait(), move up the sig block to avoid needless computation
   if the block exits the function
 * In io_cqring_wait(), protect ctx->napi_list from race condition by
   splicing it into a local list
 * In io_cqring_wait(), allow busy polling when uts is missing
 * Fix kernel test robot issues

Co-developed-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Olivier Langlois <olivier@trillion01.com>
---
 fs/io_uring.c | 238 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 229 insertions(+), 9 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4715980e9015..2759a60339d2 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -63,6 +63,7 @@
 #include <net/sock.h>
 #include <net/af_unix.h>
 #include <net/scm.h>
+#include <net/busy_poll.h>
 #include <linux/anon_inodes.h>
 #include <linux/sched/mm.h>
 #include <linux/uaccess.h>
@@ -395,6 +396,10 @@ struct io_ring_ctx {
 	struct list_head	sqd_list;
 
 	unsigned long		check_cq_overflow;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	/* used to track busy poll napi_id */
+	struct list_head	napi_list;
+#endif
 
 	struct {
 		unsigned		cached_cq_tail;
@@ -1464,6 +1469,9 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 	INIT_WQ_LIST(&ctx->locked_free_list);
 	INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
 	INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	INIT_LIST_HEAD(&ctx->napi_list);
+#endif
 	return ctx;
 err:
 	kfree(ctx->dummy_ubuf);
@@ -5399,6 +5407,103 @@ IO_NETOP_FN(send);
 IO_NETOP_FN(recv);
 #endif /* CONFIG_NET */
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
+
+#define NAPI_TIMEOUT			(60 * SEC_CONVERSION)
+
+struct napi_entry {
+	struct list_head	list;
+	unsigned int		napi_id;
+	unsigned long		timeout;
+};
+
+/*
+ * Add busy poll NAPI ID from sk.
+ */
+static void io_add_napi(struct file *file, struct io_ring_ctx *ctx)
+{
+	unsigned int napi_id;
+	struct socket *sock;
+	struct sock *sk;
+	struct napi_entry *ne;
+
+	if (!net_busy_loop_on())
+		return;
+
+	sock = sock_from_file(file);
+	if (!sock)
+		return;
+
+	sk = sock->sk;
+	if (!sk)
+		return;
+
+	napi_id = READ_ONCE(sk->sk_napi_id);
+
+	/* Non-NAPI IDs can be rejected */
+	if (napi_id < MIN_NAPI_ID)
+		return;
+
+	list_for_each_entry(ne, &ctx->napi_list, list) {
+		if (ne->napi_id == napi_id) {
+			ne->timeout = jiffies + NAPI_TIMEOUT;
+			return;
+		}
+	}
+
+	ne = kmalloc(sizeof(*ne), GFP_KERNEL);
+	if (!ne)
+		return;
+
+	ne->napi_id = napi_id;
+	ne->timeout = jiffies + NAPI_TIMEOUT;
+	list_add_tail(&ne->list, &ctx->napi_list);
+}
+
+static inline void io_check_napi_entry_timeout(struct napi_entry *ne)
+{
+	if (time_after(jiffies, ne->timeout)) {
+		list_del(&ne->list);
+		kfree(ne);
+	}
+}
+
+/*
+ * Busy poll if globally on and supporting sockets found
+ */
+static bool io_napi_busy_loop(struct list_head *napi_list)
+{
+	struct napi_entry *ne, *n;
+
+	list_for_each_entry_safe(ne, n, napi_list, list) {
+		napi_busy_loop(ne->napi_id, NULL, NULL, true,
+			       BUSY_POLL_BUDGET);
+		io_check_napi_entry_timeout(ne);
+	}
+	return !list_empty(napi_list);
+}
+
+static void io_free_napi_list(struct io_ring_ctx *ctx)
+{
+	while (!list_empty(&ctx->napi_list)) {
+		struct napi_entry *ne =
+			list_first_entry(&ctx->napi_list, struct napi_entry,
+					 list);
+
+		list_del(&ne->list);
+		kfree(ne);
+	}
+}
+#else
+static inline void io_add_napi(struct file *file, struct io_ring_ctx *ctx)
+{
+}
+
+static inline void io_free_napi_list(struct io_ring_ctx *ctx)
+{
+}
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
 struct io_poll_table {
 	struct poll_table_struct pt;
 	struct io_kiocb *req;
@@ -5777,6 +5882,7 @@ static int __io_arm_poll_handler(struct io_kiocb *req,
 		__io_poll_execute(req, mask);
 		return 0;
 	}
+	io_add_napi(req->file, req->ctx);
 
 	/*
 	 * Release ownership. If someone tried to queue a tw while it was
@@ -7519,7 +7625,11 @@ static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries)
 		    !(ctx->flags & IORING_SETUP_R_DISABLED))
 			ret = io_submit_sqes(ctx, to_submit);
 		mutex_unlock(&ctx->uring_lock);
-
+#ifdef CONFIG_NET_RX_BUSY_POLL
+		if (!list_empty(&ctx->napi_list) &&
+		    io_napi_busy_loop(&ctx->napi_list))
+			++ret;
+#endif
 		if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait))
 			wake_up(&ctx->sqo_sq_wait);
 		if (creds)
@@ -7650,6 +7760,9 @@ struct io_wait_queue {
 	struct io_ring_ctx *ctx;
 	unsigned cq_tail;
 	unsigned nr_timeouts;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	unsigned busy_poll_to;
+#endif
 };
 
 static inline bool io_should_wake(struct io_wait_queue *iowq)
@@ -7711,6 +7824,87 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
 	return 1;
 }
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
+static void io_adjust_busy_loop_timeout(struct timespec64 *ts,
+					struct io_wait_queue *iowq)
+{
+	unsigned busy_poll_to = READ_ONCE(sysctl_net_busy_poll);
+	struct timespec64 pollto = ns_to_timespec64(1000 * (s64)busy_poll_to);
+
+	if (timespec64_compare(ts, &pollto) > 0) {
+		*ts = timespec64_sub(*ts, pollto);
+		iowq->busy_poll_to = busy_poll_to;
+	} else {
+		s64 to = timespec64_to_ns(ts);
+
+		do_div(to, 1000);
+		iowq->busy_poll_to = to;
+		ts->tv_sec = 0;
+		ts->tv_nsec = 0;
+	}
+}
+
+static inline bool io_busy_loop_timeout(unsigned long start_time,
+					unsigned long bp_usec)
+{
+	if (bp_usec) {
+		unsigned long end_time = start_time + bp_usec;
+		unsigned long now = busy_loop_current_time();
+
+		return time_after(now, end_time);
+	}
+	return true;
+}
+
+static bool io_busy_loop_end(void *p, unsigned long start_time)
+{
+	struct io_wait_queue *iowq = p;
+
+	return signal_pending(current) ||
+	       io_should_wake(iowq) ||
+	       io_busy_loop_timeout(start_time, iowq->busy_poll_to);
+}
+
+static void io_blocking_napi_busy_loop(struct list_head *napi_list,
+				       struct io_wait_queue *iowq)
+{
+	unsigned long start_time =
+		list_is_singular(napi_list) ? 0 :
+		busy_loop_current_time();
+
+	do {
+		if (list_is_singular(napi_list)) {
+			struct napi_entry *ne =
+				list_first_entry(napi_list,
+						 struct napi_entry, list);
+
+			napi_busy_loop(ne->napi_id, io_busy_loop_end, iowq,
+				       true, BUSY_POLL_BUDGET);
+			io_check_napi_entry_timeout(ne);
+			break;
+		}
+	} while (io_napi_busy_loop(napi_list) &&
+		 !io_busy_loop_end(iowq, start_time));
+}
+
+static void io_putback_napi_list(struct io_ring_ctx *ctx,
+				 struct list_head *napi_list)
+{
+	struct napi_entry *cne, *lne;
+
+	mutex_lock(&ctx->uring_lock);
+	list_for_each_entry(cne, &ctx->napi_list, list)
+		list_for_each_entry(lne, napi_list, list)
+			if (cne->napi_id == lne->napi_id) {
+				list_del(&lne->list);
+				kfree(lne);
+				break;
+			}
+	list_splice(napi_list, &ctx->napi_list);
+	mutex_unlock(&ctx->uring_lock);
+}
+#endif /* CONFIG_NET_RX_BUSY_POLL */
+
 /*
  * Wait until events become available, if we don't already have some. The
  * application must reap them itself, as they reside on the shared cq ring.
@@ -7723,6 +7917,9 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	struct io_rings *rings = ctx->rings;
 	ktime_t timeout = KTIME_MAX;
 	int ret;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	LIST_HEAD(local_napi_list);
+#endif
 
 	do {
 		io_cqring_overflow_flush(ctx);
@@ -7732,14 +7929,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 			break;
 	} while (1);
 
-	if (uts) {
-		struct timespec64 ts;
-
-		if (get_timespec64(&ts, uts))
-			return -EFAULT;
-		timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
-	}
-
 	if (sig) {
 #ifdef CONFIG_COMPAT
 		if (in_compat_syscall())
@@ -7753,6 +7942,30 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 			return ret;
 	}
 
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	iowq.busy_poll_to = 0;
+	if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
+		mutex_lock(&ctx->uring_lock);
+		list_splice_init(&ctx->napi_list, &local_napi_list);
+		mutex_unlock(&ctx->uring_lock);
+	}
+#endif
+	if (uts) {
+		struct timespec64 ts;
+
+		if (get_timespec64(&ts, uts))
+			return -EFAULT;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+		if (!list_empty(&local_napi_list))
+			io_adjust_busy_loop_timeout(&ts, &iowq);
+#endif
+		timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+	}
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	else if (!list_empty(&local_napi_list))
+		iowq.busy_poll_to = READ_ONCE(sysctl_net_busy_poll);
+#endif
+
 	init_waitqueue_func_entry(&iowq.wq, io_wake_function);
 	iowq.wq.private = current;
 	INIT_LIST_HEAD(&iowq.wq.entry);
@@ -7761,6 +7974,12 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 	iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
 
 	trace_io_uring_cqring_wait(ctx, min_events);
+#ifdef CONFIG_NET_RX_BUSY_POLL
+	if (iowq.busy_poll_to)
+		io_blocking_napi_busy_loop(&local_napi_list, &iowq);
+	if (!list_empty(&local_napi_list))
+		io_putback_napi_list(ctx, &local_napi_list);
+#endif
 	do {
 		/* if we can't even flush overflow, don't wait for more */
 		if (!io_cqring_overflow_flush(ctx)) {
@@ -9450,6 +9669,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 		__io_sqe_files_unregister(ctx);
 	if (ctx->rings)
 		__io_cqring_overflow_flush(ctx, true);
+	io_free_napi_list(ctx);
 	mutex_unlock(&ctx->uring_lock);
 	io_eventfd_unregister(ctx);
 	io_destroy_buffers(ctx);
-- 
2.35.1

Re: [PATCH v2] io_uring: Add support for napi_busy_poll

[kernel test robot]

Hi Olivier,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.17-rc5 next-20220225]
[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]

url:    https://github.com/0day-ci/linux/commits/Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2293be58d6a18cab800e25e42081bacb75c05752
config: mips-qi_lb60_defconfig (https://download.01.org/0day-ci/archive/20220228/202202280457.dz7FiDNh-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://github.com/0day-ci/linux/commit/65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
        git checkout 65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> fs/io_uring.c:7840:3: warning: comparison of distinct pointer types ('typeof ((to)) *' (aka 'long long *') and 'uint64_t *' (aka 'unsigned long long *')) [-Wcompare-distinct-pointer-types]
                   do_div(to, 1000);
                   ^~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:222:28: note: expanded from macro 'do_div'
           (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
                  ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~
   1 warning generated.


vim +7840 fs/io_uring.c

  7826	
  7827	#ifdef CONFIG_NET_RX_BUSY_POLL
  7828	static void io_adjust_busy_loop_timeout(struct timespec64 *ts,
  7829						struct io_wait_queue *iowq)
  7830	{
  7831		unsigned busy_poll_to = READ_ONCE(sysctl_net_busy_poll);
  7832		struct timespec64 pollto = ns_to_timespec64(1000 * (s64)busy_poll_to);
  7833	
  7834		if (timespec64_compare(ts, &pollto) > 0) {
  7835			*ts = timespec64_sub(*ts, pollto);
  7836			iowq->busy_poll_to = busy_poll_to;
  7837		} else {
  7838			s64 to = timespec64_to_ns(ts);
  7839	
> 7840			do_div(to, 1000);
  7841			iowq->busy_poll_to = to;
  7842			ts->tv_sec = 0;
  7843			ts->tv_nsec = 0;
  7844		}
  7845	}
  7846	

---
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https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH v2] io_uring: Add support for napi_busy_poll

[kernel test robot]

Hi Olivier,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.17-rc5 next-20220225]
[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]

url:    https://github.com/0day-ci/linux/commits/Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2293be58d6a18cab800e25e42081bacb75c05752
config: arc-randconfig-r043-20220227 (https://download.01.org/0day-ci/archive/20220228/202202280400.HHUsYqhX-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
        git checkout 65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   fs/io_uring.c: In function '__io_submit_flush_completions':
   fs/io_uring.c:2531:40: warning: variable 'prev' set but not used [-Wunused-but-set-variable]
    2531 |         struct io_wq_work_node *node, *prev;
         |                                        ^~~~
   In file included from ./arch/arc/include/generated/asm/div64.h:1,
                    from include/linux/math.h:5,
                    from include/linux/kernel.h:25,
                    from fs/io_uring.c:42:
   fs/io_uring.c: In function 'io_adjust_busy_loop_timeout':
>> include/asm-generic/div64.h:222:35: warning: comparison of distinct pointer types lacks a cast
     222 |         (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
         |                                   ^~
   fs/io_uring.c:7840:17: note: in expansion of macro 'do_div'
    7840 |                 do_div(to, 1000);
         |                 ^~~~~~


vim +222 include/asm-generic/div64.h

^1da177e4c3f41 Linus Torvalds     2005-04-16  215  
^1da177e4c3f41 Linus Torvalds     2005-04-16  216  /* The unnecessary pointer compare is there
^1da177e4c3f41 Linus Torvalds     2005-04-16  217   * to check for type safety (n must be 64bit)
^1da177e4c3f41 Linus Torvalds     2005-04-16  218   */
^1da177e4c3f41 Linus Torvalds     2005-04-16  219  # define do_div(n,base) ({				\
^1da177e4c3f41 Linus Torvalds     2005-04-16  220  	uint32_t __base = (base);			\
^1da177e4c3f41 Linus Torvalds     2005-04-16  221  	uint32_t __rem;					\
^1da177e4c3f41 Linus Torvalds     2005-04-16 @222  	(void)(((typeof((n)) *)0) == ((uint64_t *)0));	\
911918aa7ef6f8 Nicolas Pitre      2015-11-02  223  	if (__builtin_constant_p(__base) &&		\
911918aa7ef6f8 Nicolas Pitre      2015-11-02  224  	    is_power_of_2(__base)) {			\
911918aa7ef6f8 Nicolas Pitre      2015-11-02  225  		__rem = (n) & (__base - 1);		\
911918aa7ef6f8 Nicolas Pitre      2015-11-02  226  		(n) >>= ilog2(__base);			\
c747ce4706190e Geert Uytterhoeven 2021-08-11  227  	} else if (__builtin_constant_p(__base) &&	\
461a5e51060c93 Nicolas Pitre      2015-10-30  228  		   __base != 0) {			\
461a5e51060c93 Nicolas Pitre      2015-10-30  229  		uint32_t __res_lo, __n_lo = (n);	\
461a5e51060c93 Nicolas Pitre      2015-10-30  230  		(n) = __div64_const32(n, __base);	\
461a5e51060c93 Nicolas Pitre      2015-10-30  231  		/* the remainder can be computed with 32-bit regs */ \
461a5e51060c93 Nicolas Pitre      2015-10-30  232  		__res_lo = (n);				\
461a5e51060c93 Nicolas Pitre      2015-10-30  233  		__rem = __n_lo - __res_lo * __base;	\
911918aa7ef6f8 Nicolas Pitre      2015-11-02  234  	} else if (likely(((n) >> 32) == 0)) {		\
^1da177e4c3f41 Linus Torvalds     2005-04-16  235  		__rem = (uint32_t)(n) % __base;		\
^1da177e4c3f41 Linus Torvalds     2005-04-16  236  		(n) = (uint32_t)(n) / __base;		\
c747ce4706190e Geert Uytterhoeven 2021-08-11  237  	} else {					\
^1da177e4c3f41 Linus Torvalds     2005-04-16  238  		__rem = __div64_32(&(n), __base);	\
c747ce4706190e Geert Uytterhoeven 2021-08-11  239  	}						\
^1da177e4c3f41 Linus Torvalds     2005-04-16  240  	__rem;						\
^1da177e4c3f41 Linus Torvalds     2005-04-16  241   })
^1da177e4c3f41 Linus Torvalds     2005-04-16  242  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH v2] io_uring: Add support for napi_busy_poll

[kernel test robot]

Hi Olivier,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.17-rc5 next-20220225]
[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]

url:    https://github.com/0day-ci/linux/commits/Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2293be58d6a18cab800e25e42081bacb75c05752
config: mips-buildonly-randconfig-r006-20220227 (https://download.01.org/0day-ci/archive/20220228/202202280543.0QW3T3id-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://github.com/0day-ci/linux/commit/65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
        git checkout 65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        # save the config file to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> fs/io_uring.c:7840:3: warning: comparison of distinct pointer types ('typeof ((to)) (aka 'long long and 'uint64_t (aka 'unsigned long long
   do_div(to, 1000);
   ^~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:222:28: note: expanded from macro 'do_div'
   (void)(((typeof((n)) == ((uint64_t ~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~
   fatal error: error in backend: Nested variants found in inline asm string: ' .set push
   .set mips64r2
   .if ( 0x00 ) != -1)) 0x00 ) != -1)) : ($( static struct ftrace_branch_data __attribute__((__aligned__(4))) __attribute__((__section__("_ftrace_branch"))) __if_trace = $( .func = __func__, .file = "arch/mips/include/asm/atomic.h", .line = 155, $); 0x00 ) != -1)) : $))) ) && ( 0 ); .set push; .set mips64r2; .rept 1; sync 0x00; .endr; .set pop; .else; ; .endif
   1: ll $0, $1 # atomic_add
   addu $0, $2
   sc $0, $1
   beqz $0, 1b
   .set pop
   '
   PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
   Stack dump:
   0. Program arguments: clang -Wp,-MMD,fs/.io_uring.o.d -nostdinc -Iarch/mips/include -I./arch/mips/include/generated -Iinclude -I./include -Iarch/mips/include/uapi -I./arch/mips/include/generated/uapi -Iinclude/uapi -I./include/generated/uapi -include include/linux/compiler-version.h -include include/linux/kconfig.h -include include/linux/compiler_types.h -D__KERNEL__ -DVMLINUX_LOAD_ADDRESS=0xffffffff80002000 -DLINKER_LOAD_ADDRESS=0x80002000 -DDATAOFFSET=0 -Qunused-arguments -fmacro-prefix-map== -DKBUILD_EXTRA_WARN1 -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -Werror=implicit-function-declaration -Werror=implicit-int -Werror=return-type -Wno-format-security -std=gnu89 --target=mips-linux -fintegrated-as -Werror=unknown-warning-option -Werror=ignored-optimization-argument -mno-check-zero-division -mabi=32 -G 0 -mno-abicalls -fno-pic -pipe -msoft-float -DGAS_HAS_SET_HARDFLOAT -Wa,-msoft-float -ffreestanding -EB -fno-stack-check -march=mips32 -Wa,--trap -DTOOLCHAIN_SUPPORTS_VIRT -Iarch/mips/include/asm/mach-lantiq -Iarch/mips/include/asm/mach-lantiq/xway -Iarch/mips/include/asm/mach-generic -fno-asynchronous-unwind-tables -fno-delete-null-pointer-checks -Wno-frame-address -Wno-address-of-packed-member -O2 -Wframe-larger-than=1024 -fstack-protector-strong -Wimplicit-fallthrough -Wno-gnu -mno-global-merge -Wno-unused-but-set-variable -Wno-unused-const-variable -ftrivial-auto-var-init=pattern -fno-stack-clash-protection -pg -Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wcast-function-type -Wno-array-bounds -fno-strict-overflow -fno-stack-check -Werror=date-time -Werror=incompatible-pointer-types -Wextra -Wunused -Wno-unused-parameter -Wmissing-declarations -Wmissing-format-attribute -Wmissing-prototypes -Wold-style-definition -Wmissing-include-dirs -Wunused-but-set-variable -Wunused-const-variable -Wno-missing-field-initializers -Wno-sign-compare -Wno-type-limits -I fs -I ./fs -DKBUILD_MODFILE="fs/io_uring" -DKBUILD_BASENAME="io_uring" -DKBUILD_MODNAME="io_uring" -D__KBUILD_MODNAME=kmod_io_uring -c -o fs/io_uring.o fs/io_uring.c
   1. <eof> parser at end of file
   2. Code generation
   3. Running pass 'Function Pass Manager' on module 'fs/io_uring.c'.
   4. Running pass 'Mips Assembly Printer' on function '@io_uring_cancel_generic'
   #0 0x000055a23ff64d7f Signals.cpp:0:0
   #1 0x000055a23ff62c5c llvm::sys::CleanupOnSignal(unsigned long) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x348ec5c)
   #2 0x000055a23fea2fd7 llvm::CrashRecoveryContext::HandleExit(int) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x33cefd7)
   #3 0x000055a23ff5b30e llvm::sys::Process::Exit(int, bool) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x348730e)
   #4 0x000055a23db86ccb (/opt/cross/clang-d271fc04d5/bin/clang-15+0x10b2ccb)
   #5 0x000055a23fea9a8c llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x33d5a8c)
   #6 0x000055a240bb35c0 llvm::AsmPrinter::emitInlineAsm(llvm::MachineInstr const (/opt/cross/clang-d271fc04d5/bin/clang-15+0x40df5c0)
   #7 0x000055a240baf4f4 llvm::AsmPrinter::emitFunctionBody() (/opt/cross/clang-d271fc04d5/bin/clang-15+0x40db4f4)
   #8 0x000055a23e5f0887 llvm::MipsAsmPrinter::runOnMachineFunction(llvm::MachineFunction&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x1b1c887)
   #9 0x000055a23f2ad54d llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.53) MachineFunctionPass.cpp:0:0
   #10 0x000055a23f6f4807 llvm::FPPassManager::runOnFunction(llvm::Function&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x2c20807)
   #11 0x000055a23f6f4981 llvm::FPPassManager::runOnModule(llvm::Module&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x2c20981)
   #12 0x000055a23f6f54ff llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x2c214ff)
   #13 0x000055a24027f147 clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream> >) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x37ab147)
   #14 0x000055a240ecd693 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x43f9693)
   #15 0x000055a2419a86e9 clang::ParseAST(clang::Sema&, bool, bool) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x4ed46e9)
   #16 0x000055a240ecc4cf clang::CodeGenAction::ExecuteAction() (/opt/cross/clang-d271fc04d5/bin/clang-15+0x43f84cf)
   #17 0x000055a2408cf561 clang::FrontendAction::Execute() (/opt/cross/clang-d271fc04d5/bin/clang-15+0x3dfb561)
   #18 0x000055a240865faa clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x3d91faa)
   #19 0x000055a240993cbb (/opt/cross/clang-d271fc04d5/bin/clang-15+0x3ebfcbb)
   #20 0x000055a23db8827c cc1_main(llvm::ArrayRef<char char (/opt/cross/clang-d271fc04d5/bin/clang-15+0x10b427c)
   #21 0x000055a23db84f4b ExecuteCC1Tool(llvm::SmallVectorImpl<char driver.cpp:0:0
   #22 0x000055a2406fed95 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> const::'lambda'()>(long) Job.cpp:0:0
   #23 0x000055a23fea2e93 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x33cee93)
   #24 0x000055a2406ff68e clang::driver::CC1Command::Execute(llvm::ArrayRef<llvm::Optional<llvm::StringRef> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> const (.part.216) Job.cpp:0:0
   #25 0x000055a2406d4267 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const (/opt/cross/clang-d271fc04d5/bin/clang-15+0x3c00267)
   #26 0x000055a2406d4c47 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command >&) const (/opt/cross/clang-d271fc04d5/bin/clang-15+0x3c00c47)
   #27 0x000055a2406de2f9 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command >&) (/opt/cross/clang-d271fc04d5/bin/clang-15+0x3c0a2f9)
   #28 0x000055a23daad63f main (/opt/cross/clang-d271fc04d5/bin/clang-15+0xfd963f)
   #29 0x00007f38edb9bd0a __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x26d0a)
   #30 0x000055a23db84a6a _start (/opt/cross/clang-d271fc04d5/bin/clang-15+0x10b0a6a)
   clang-15: error: clang frontend command failed with exit code 70 (use -v to see invocation)
   clang version 15.0.0 (git://gitmirror/llvm_project d271fc04d5b97b12e6b797c6067d3c96a8d7470e)
   Target: mips-unknown-linux
   Thread model: posix
   InstalledDir: /opt/cross/clang-d271fc04d5/bin
   clang-15: note: diagnostic msg:
   Makefile arch block certs crypto drivers fs include init ipc kernel lib mm net nr_bisected scripts security sound source usr virt


vim +7840 fs/io_uring.c

  7826	
  7827	#ifdef CONFIG_NET_RX_BUSY_POLL
  7828	static void io_adjust_busy_loop_timeout(struct timespec64 *ts,
  7829						struct io_wait_queue *iowq)
  7830	{
  7831		unsigned busy_poll_to = READ_ONCE(sysctl_net_busy_poll);
  7832		struct timespec64 pollto = ns_to_timespec64(1000 * (s64)busy_poll_to);
  7833	
  7834		if (timespec64_compare(ts, &pollto) > 0) {
  7835			*ts = timespec64_sub(*ts, pollto);
  7836			iowq->busy_poll_to = busy_poll_to;
  7837		} else {
  7838			s64 to = timespec64_to_ns(ts);
  7839	
> 7840			do_div(to, 1000);
  7841			iowq->busy_poll_to = to;
  7842			ts->tv_sec = 0;
  7843			ts->tv_nsec = 0;
  7844		}
  7845	}
  7846	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

Re: [PATCH v2] io_uring: Add support for napi_busy_poll

[kernel test robot]

Hi Olivier,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.17-rc6]
[cannot apply to next-20220225]
[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]

url:    https://github.com/0day-ci/linux/commits/Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 2293be58d6a18cab800e25e42081bacb75c05752
config: mips-randconfig-s032-20220228 (https://download.01.org/0day-ci/archive/20220228/202202281457.NLF9dxdF-lkp@intel.com/config)
compiler: mipsel-linux-gcc (GCC) 11.2.0
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-dirty
        # https://github.com/0day-ci/linux/commit/65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Olivier-Langlois/io_uring-Add-support-for-napi_busy_poll/20220228-012140
        git checkout 65e72f78c66272f7cf0e87dfeef88f5b79de2d91
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=mips SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


sparse warnings: (new ones prefixed by >>)
   command-line: note: in included file:
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_ACQUIRE redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_SEQ_CST redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_ACQ_REL redefined
   builtin:0:0: sparse: this was the original definition
   builtin:1:9: sparse: sparse: preprocessor token __ATOMIC_RELEASE redefined
   builtin:0:0: sparse: this was the original definition
   fs/io_uring.c: note: in included file (through include/trace/trace_events.h, include/trace/define_trace.h, include/trace/events/io_uring.h):
   include/trace/events/io_uring.h:509:1: sparse: sparse: incorrect type in assignment (different base types) @@     expected unsigned int [usertype] op_flags @@     got restricted __kernel_rwf_t const [usertype] rw_flags @@
   include/trace/events/io_uring.h:509:1: sparse:     expected unsigned int [usertype] op_flags
   include/trace/events/io_uring.h:509:1: sparse:     got restricted __kernel_rwf_t const [usertype] rw_flags
   fs/io_uring.c:3257:24: sparse: sparse: incorrect type in return expression (different address spaces) @@     expected void [noderef] __user * @@     got struct io_buffer *[assigned] kbuf @@
   fs/io_uring.c:3257:24: sparse:     expected void [noderef] __user *
   fs/io_uring.c:3257:24: sparse:     got struct io_buffer *[assigned] kbuf
   fs/io_uring.c:4803:14: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected struct file *file @@     got struct file [noderef] __rcu * @@
   fs/io_uring.c:4803:14: sparse:     expected struct file *file
   fs/io_uring.c:4803:14: sparse:     got struct file [noderef] __rcu *
   fs/io_uring.c:5637:37: sparse: sparse: incorrect type in assignment (different base types) @@     expected unsigned int [usertype] result @@     got restricted __poll_t @@
   fs/io_uring.c:5637:37: sparse:     expected unsigned int [usertype] result
   fs/io_uring.c:5637:37: sparse:     got restricted __poll_t
   fs/io_uring.c:5642:71: sparse: sparse: restricted __poll_t degrades to integer
   fs/io_uring.c:5642:65: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected restricted __poll_t [usertype] val @@     got unsigned int @@
   fs/io_uring.c:5642:65: sparse:     expected restricted __poll_t [usertype] val
   fs/io_uring.c:5642:65: sparse:     got unsigned int
   fs/io_uring.c:5642:52: sparse: sparse: incorrect type in initializer (different base types) @@     expected restricted __poll_t [usertype] mask @@     got unsigned short @@
   fs/io_uring.c:5642:52: sparse:     expected restricted __poll_t [usertype] mask
   fs/io_uring.c:5642:52: sparse:     got unsigned short
   fs/io_uring.c:5646:71: sparse: sparse: incorrect type in argument 3 (different base types) @@     expected signed int [usertype] res @@     got restricted __poll_t [usertype] mask @@
   fs/io_uring.c:5646:71: sparse:     expected signed int [usertype] res
   fs/io_uring.c:5646:71: sparse:     got restricted __poll_t [usertype] mask
   fs/io_uring.c:5676:66: sparse: sparse: restricted __poll_t degrades to integer
   fs/io_uring.c:5676:55: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected restricted __poll_t [usertype] val @@     got unsigned int @@
   fs/io_uring.c:5676:55: sparse:     expected restricted __poll_t [usertype] val
   fs/io_uring.c:5676:55: sparse:     got unsigned int
   fs/io_uring.c:5778:40: sparse: sparse: incorrect type in argument 2 (different base types) @@     expected int mask @@     got restricted __poll_t [usertype] mask @@
   fs/io_uring.c:5778:40: sparse:     expected int mask
   fs/io_uring.c:5778:40: sparse:     got restricted __poll_t [usertype] mask
   fs/io_uring.c:5865:24: sparse: sparse: incorrect type in return expression (different base types) @@     expected int @@     got restricted __poll_t [assigned] [usertype] mask @@
   fs/io_uring.c:5865:24: sparse:     expected int
   fs/io_uring.c:5865:24: sparse:     got restricted __poll_t [assigned] [usertype] mask
   fs/io_uring.c:5882:40: sparse: sparse: incorrect type in argument 2 (different base types) @@     expected int mask @@     got restricted __poll_t [assigned] [usertype] mask @@
   fs/io_uring.c:5882:40: sparse:     expected int mask
   fs/io_uring.c:5882:40: sparse:     got restricted __poll_t [assigned] [usertype] mask
   fs/io_uring.c:5918:25: sparse: sparse: restricted __poll_t degrades to integer
   fs/io_uring.c:5918:48: sparse: sparse: incorrect type in initializer (different base types) @@     expected restricted __poll_t [usertype] mask @@     got unsigned int @@
   fs/io_uring.c:5918:48: sparse:     expected restricted __poll_t [usertype] mask
   fs/io_uring.c:5918:48: sparse:     got unsigned int
   fs/io_uring.c:5927:22: sparse: sparse: invalid assignment: |=
   fs/io_uring.c:5927:22: sparse:    left side has type restricted __poll_t
   fs/io_uring.c:5927:22: sparse:    right side has type int
   fs/io_uring.c:5932:30: sparse: sparse: invalid assignment: &=
   fs/io_uring.c:5932:30: sparse:    left side has type restricted __poll_t
   fs/io_uring.c:5932:30: sparse:    right side has type int
   fs/io_uring.c:5934:22: sparse: sparse: invalid assignment: |=
   fs/io_uring.c:5934:22: sparse:    left side has type restricted __poll_t
   fs/io_uring.c:5934:22: sparse:    right side has type int
   fs/io_uring.c:5950:33: sparse: sparse: incorrect type in argument 5 (different base types) @@     expected int mask @@     got restricted __poll_t [usertype] mask @@
   fs/io_uring.c:5950:33: sparse:     expected int mask
   fs/io_uring.c:5950:33: sparse:     got restricted __poll_t [usertype] mask
   fs/io_uring.c:5950:50: sparse: sparse: incorrect type in argument 6 (different base types) @@     expected int events @@     got restricted __poll_t [usertype] events @@
   fs/io_uring.c:5950:50: sparse:     expected int events
   fs/io_uring.c:5950:50: sparse:     got restricted __poll_t [usertype] events
   fs/io_uring.c:6031:24: sparse: sparse: invalid assignment: |=
   fs/io_uring.c:6031:24: sparse:    left side has type unsigned int
   fs/io_uring.c:6031:24: sparse:    right side has type restricted __poll_t
   fs/io_uring.c:6032:65: sparse: sparse: restricted __poll_t degrades to integer
   fs/io_uring.c:6032:29: sparse: sparse: restricted __poll_t degrades to integer
   fs/io_uring.c:6032:38: sparse: sparse: incorrect type in return expression (different base types) @@     expected restricted __poll_t @@     got unsigned int @@
   fs/io_uring.c:6032:38: sparse:     expected restricted __poll_t
   fs/io_uring.c:6032:38: sparse:     got unsigned int
   fs/io_uring.c:6122:43: sparse: sparse: invalid assignment: &=
   fs/io_uring.c:6122:43: sparse:    left side has type restricted __poll_t
   fs/io_uring.c:6122:43: sparse:    right side has type int
   fs/io_uring.c:6123:62: sparse: sparse: restricted __poll_t degrades to integer
   fs/io_uring.c:6123:43: sparse: sparse: invalid assignment: |=
   fs/io_uring.c:6123:43: sparse:    left side has type restricted __poll_t
   fs/io_uring.c:6123:43: sparse:    right side has type unsigned int
>> fs/io_uring.c:7840:17: sparse: sparse: incompatible types in comparison expression (different signedness):
>> fs/io_uring.c:7840:17: sparse:    signed long long *
>> fs/io_uring.c:7840:17: sparse:    unsigned long long [usertype] *
   fs/io_uring.c:2294:17: sparse: sparse: context imbalance in 'handle_prev_tw_list' - different lock contexts for basic block
   fs/io_uring.c:8293:9: sparse: sparse: context imbalance in 'io_sq_thread_unpark' - wrong count at exit
   fs/io_uring.c:8304:9: sparse: sparse: context imbalance in 'io_sq_thread_park' - wrong count at exit

vim +7840 fs/io_uring.c

  7826	
  7827	#ifdef CONFIG_NET_RX_BUSY_POLL
  7828	static void io_adjust_busy_loop_timeout(struct timespec64 *ts,
  7829						struct io_wait_queue *iowq)
  7830	{
  7831		unsigned busy_poll_to = READ_ONCE(sysctl_net_busy_poll);
  7832		struct timespec64 pollto = ns_to_timespec64(1000 * (s64)busy_poll_to);
  7833	
  7834		if (timespec64_compare(ts, &pollto) > 0) {
  7835			*ts = timespec64_sub(*ts, pollto);
  7836			iowq->busy_poll_to = busy_poll_to;
  7837		} else {
  7838			s64 to = timespec64_to_ns(ts);
  7839	
> 7840			do_div(to, 1000);
  7841			iowq->busy_poll_to = to;
  7842			ts->tv_sec = 0;
  7843			ts->tv_nsec = 0;
  7844		}
  7845	}
  7846	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org