Experimental support for submitting and completing IO through rings shared between the application and kernel.
The submission rings are struct iocb, like we would submit through io_submit(), and the completion rings are struct io_event, like we would pass in (and copy back) from io_getevents(). A new system call is added for this, io_ring_enter(). This system call submits IO that is queued in the SQ ring, and/or completes IO and stores the results in the CQ ring. This could be augmented with a kernel thread that does the submission and polling, then the application would never have to enter the kernel to do IO. Sample application: http://git.kernel.dk/cgit/fio/plain/t/aio-ring.c Signed-off-by: Jens Axboe <[email protected]> --- arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/aio.c | 484 +++++++++++++++++++++++-- include/linux/syscalls.h | 4 +- include/uapi/linux/aio_abi.h | 29 ++ kernel/sys_ni.c | 1 + 5 files changed, 493 insertions(+), 26 deletions(-) diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 67c357225fb0..55a26700a637 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -344,6 +344,7 @@ 333 common io_pgetevents __x64_sys_io_pgetevents 334 common rseq __x64_sys_rseq 335 common io_setup2 __x64_sys_io_setup2 +336 common io_ring_enter __x64_sys_io_ring_enter # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/aio.c b/fs/aio.c index fda9b1c53f3d..a5ec349670bc 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -92,6 +92,18 @@ struct ctx_rq_wait { atomic_t count; }; +struct aio_mapped_range { + struct page **pages; + long nr_pages; +}; + +struct aio_iocb_ring { + struct aio_mapped_range ring_range; /* maps user SQ ring */ + struct aio_sq_ring *ring; + + struct aio_mapped_range iocb_range; /* maps user iocbs */ +}; + struct kioctx { struct percpu_ref users; atomic_t dead; @@ -127,6 +139,11 @@ struct kioctx { struct page **ring_pages; long nr_pages; + /* if used, completion and submission rings */ + struct aio_iocb_ring sq_ring; + struct aio_mapped_range cq_ring; + int cq_ring_overflow; + struct rcu_work free_rwork; /* see free_ioctx() */ /* @@ -280,6 +297,13 @@ static struct vfsmount *aio_mnt; static const struct file_operations aio_ring_fops; static const struct address_space_operations aio_ctx_aops; +static const unsigned int array_page_shift = + ilog2(PAGE_SIZE / sizeof(u32)); +static const unsigned int iocb_page_shift = + ilog2(PAGE_SIZE / sizeof(struct iocb)); +static const unsigned int event_page_shift = + ilog2(PAGE_SIZE / sizeof(struct io_event)); + /* * We rely on block level unplugs to flush pending requests, if we schedule */ @@ -289,6 +313,7 @@ static const bool aio_use_state_req_list = true; static const bool aio_use_state_req_list = false; #endif +static void aio_scqring_unmap(struct kioctx *); static void aio_iopoll_reap_events(struct kioctx *); static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) @@ -519,6 +544,12 @@ static const struct address_space_operations aio_ctx_aops = { #endif }; +/* Polled IO or SQ/CQ rings don't use the old ring */ +static bool aio_ctx_old_ring(struct kioctx *ctx) +{ + return !(ctx->flags & (IOCTX_FLAG_IOPOLL | IOCTX_FLAG_SCQRING)); +} + static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) { struct aio_ring *ring; @@ -533,7 +564,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) * IO polling doesn't require any io event entries */ size = sizeof(struct aio_ring); - if (!(ctx->flags & IOCTX_FLAG_IOPOLL)) { + if (aio_ctx_old_ring(ctx)) { nr_events += 2; /* 1 is required, 2 for good luck */ size += sizeof(struct io_event) * nr_events; } @@ -625,7 +656,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) */ static bool aio_ctx_supports_cancel(struct kioctx *ctx) { - return (ctx->flags & IOCTX_FLAG_IOPOLL) == 0; + return (ctx->flags & (IOCTX_FLAG_IOPOLL | IOCTX_FLAG_SCQRING)) == 0; } #define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) @@ -661,6 +692,7 @@ static void free_ioctx(struct work_struct *work) free_rwork); pr_debug("freeing %p\n", ctx); + aio_scqring_unmap(ctx); aio_free_ring(ctx); free_percpu(ctx->cpu); percpu_ref_exit(&ctx->reqs); @@ -1205,6 +1237,39 @@ static void aio_fill_event(struct io_event *ev, struct aio_kiocb *iocb, ev->res2 = res2; } +static void aio_commit_cqring(struct kioctx *ctx, unsigned next_tail) +{ + struct aio_cq_ring *ring = page_address(ctx->cq_ring.pages[0]); + + if (next_tail != ring->tail) { + ring->tail = next_tail; + smp_wmb(); + } +} + +static struct io_event *aio_peek_cqring(struct kioctx *ctx, unsigned *ntail) +{ + struct aio_cq_ring *ring; + struct io_event *ev; + unsigned tail; + + ring = page_address(ctx->cq_ring.pages[0]); + + smp_rmb(); + tail = READ_ONCE(ring->tail); + *ntail = tail + 1; + if (*ntail == ring->nr_events) + *ntail = 0; + if (*ntail == READ_ONCE(ring->head)) + return NULL; + + /* io_event array starts offset one into the mapped range */ + tail++; + ev = page_address(ctx->cq_ring.pages[tail >> event_page_shift]); + tail &= ((1 << event_page_shift) - 1); + return ev + tail; +} + static void aio_ring_complete(struct kioctx *ctx, struct aio_kiocb *iocb, long res, long res2) { @@ -1266,7 +1331,36 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2) { struct kioctx *ctx = iocb->ki_ctx; - aio_ring_complete(ctx, iocb, res, res2); + if (ctx->flags & IOCTX_FLAG_SCQRING) { + unsigned long flags; + struct io_event *ev; + unsigned int tail; + + /* + * If we can't get a cq entry, userspace overflowed the + * submission (by quite a lot). Flag it as an overflow + * condition, and next io_ring_enter(2) call will return + * -EOVERFLOW. + */ + spin_lock_irqsave(&ctx->completion_lock, flags); + ev = aio_peek_cqring(ctx, &tail); + if (ev) { + aio_fill_event(ev, iocb, res, res2); + aio_commit_cqring(ctx, tail); + } else + ctx->cq_ring_overflow = 1; + spin_unlock_irqrestore(&ctx->completion_lock, flags); + } else { + aio_ring_complete(ctx, iocb, res, res2); + + /* + * We have to order our ring_info tail store above and test + * of the wait list below outside the wait lock. This is + * like in wake_up_bit() where clearing a bit has to be + * ordered with the unlocked test. + */ + smp_mb(); + } /* * Check if the user asked us to deliver the result through an @@ -1278,14 +1372,6 @@ static void aio_complete(struct aio_kiocb *iocb, long res, long res2) eventfd_ctx_put(iocb->ki_eventfd); } - /* - * We have to order our ring_info tail store above and test - * of the wait list below outside the wait lock. This is - * like in wake_up_bit() where clearing a bit has to be - * ordered with the unlocked test. - */ - smp_mb(); - if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); iocb_put(iocb); @@ -1408,6 +1494,9 @@ static long aio_iopoll_reap(struct kioctx *ctx, struct io_event __user *evs, return 0; list_for_each_entry_safe(iocb, n, &ctx->poll_completing, ki_list) { + struct io_event *ev = NULL; + unsigned int next_tail; + if (*nr_events == max) break; if (!test_bit(KIOCB_F_POLL_COMPLETED, &iocb->ki_flags)) @@ -1415,6 +1504,14 @@ static long aio_iopoll_reap(struct kioctx *ctx, struct io_event __user *evs, if (to_free == AIO_IOPOLL_BATCH) iocb_put_many(ctx, iocbs, &to_free); + /* Will only happen if the application over-commits */ + ret = -EAGAIN; + if (ctx->flags & IOCTX_FLAG_SCQRING) { + ev = aio_peek_cqring(ctx, &next_tail); + if (!ev) + break; + } + list_del(&iocb->ki_list); iocbs[to_free++] = iocb; @@ -1433,8 +1530,11 @@ static long aio_iopoll_reap(struct kioctx *ctx, struct io_event __user *evs, file_count = 1; } - if (evs && copy_to_user(evs + *nr_events, &iocb->ki_ev, - sizeof(iocb->ki_ev))) { + if (ev) { + memcpy(ev, &iocb->ki_ev, sizeof(*ev)); + aio_commit_cqring(ctx, next_tail); + } else if (evs && copy_to_user(evs + *nr_events, &iocb->ki_ev, + sizeof(iocb->ki_ev))) { ret = -EFAULT; break; } @@ -1615,24 +1715,139 @@ static long read_events(struct kioctx *ctx, long min_nr, long nr, return ret; } +static void aio_unmap_range(struct aio_mapped_range *range) +{ + int i; + + if (!range->nr_pages) + return; + + for (i = 0; i < range->nr_pages; i++) + put_page(range->pages[i]); + + kfree(range->pages); + range->pages = NULL; + range->nr_pages = 0; +} + +static int aio_map_range(struct aio_mapped_range *range, void __user *uaddr, + size_t size, int gup_flags) +{ + int nr_pages, ret; + + if ((unsigned long) uaddr & ~PAGE_MASK) + return -EINVAL; + + nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; + + range->pages = kzalloc(nr_pages * sizeof(struct page *), GFP_KERNEL); + if (!range->pages) + return -ENOMEM; + + down_write(¤t->mm->mmap_sem); + ret = get_user_pages((unsigned long) uaddr, nr_pages, gup_flags, + range->pages, NULL); + up_write(¤t->mm->mmap_sem); + + if (ret < nr_pages) { + kfree(range->pages); + return -ENOMEM; + } + + range->nr_pages = nr_pages; + return 0; +} + +static void aio_scqring_unmap(struct kioctx *ctx) +{ + aio_unmap_range(&ctx->sq_ring.ring_range); + aio_unmap_range(&ctx->sq_ring.iocb_range); + aio_unmap_range(&ctx->cq_ring); +} + +static int aio_scqring_map(struct kioctx *ctx, + struct aio_sq_ring __user *sq_ring, + struct aio_cq_ring __user *cq_ring) +{ + int ret, sq_ring_size, cq_ring_size; + struct aio_cq_ring *kcq_ring; + void __user *uptr; + size_t size; + + /* Two is the minimum size we can support. */ + if (ctx->max_reqs < 2) + return -EINVAL; + + /* + * The CQ ring size is QD + 1, so we don't have to track full condition + * for head == tail. The SQ ring we make twice that in size, to make + * room for having more inflight than the QD. + */ + sq_ring_size = ctx->max_reqs; + cq_ring_size = 2 * ctx->max_reqs; + + /* Map SQ ring and iocbs */ + size = sizeof(struct aio_sq_ring) + sq_ring_size * sizeof(u32); + ret = aio_map_range(&ctx->sq_ring.ring_range, sq_ring, size, FOLL_WRITE); + if (ret) + return ret; + + ctx->sq_ring.ring = page_address(ctx->sq_ring.ring_range.pages[0]); + if (ctx->sq_ring.ring->nr_events < sq_ring_size) { + ret = -EFAULT; + goto err; + } + ctx->sq_ring.ring->nr_events = sq_ring_size; + ctx->sq_ring.ring->head = ctx->sq_ring.ring->tail = 0; + + size = sizeof(struct iocb) * sq_ring_size; + uptr = (void __user *) (unsigned long) ctx->sq_ring.ring->iocbs; + ret = aio_map_range(&ctx->sq_ring.iocb_range, uptr, size, 0); + if (ret) + goto err; + + /* Map CQ ring and io_events */ + size = sizeof(struct aio_cq_ring) + + cq_ring_size * sizeof(struct io_event); + ret = aio_map_range(&ctx->cq_ring, cq_ring, size, FOLL_WRITE); + if (ret) + goto err; + + kcq_ring = page_address(ctx->cq_ring.pages[0]); + if (kcq_ring->nr_events < cq_ring_size) { + ret = -EFAULT; + goto err; + } + kcq_ring->nr_events = cq_ring_size; + kcq_ring->head = kcq_ring->tail = 0; + +err: + if (ret) { + aio_unmap_range(&ctx->sq_ring.ring_range); + aio_unmap_range(&ctx->sq_ring.iocb_range); + aio_unmap_range(&ctx->cq_ring); + } + return ret; +} + /* sys_io_setup2: * Like sys_io_setup(), except that it takes a set of flags * (IOCTX_FLAG_*), and some pointers to user structures: * - * *user1 - reserved for future use + * *sq_ring - pointer to the userspace SQ ring, if used. * - * *user2 - reserved for future use. + * *cq_ring - pointer to the userspace CQ ring, if used. */ -SYSCALL_DEFINE5(io_setup2, u32, nr_events, u32, flags, void __user *, user1, - void __user *, user2, aio_context_t __user *, ctxp) +SYSCALL_DEFINE5(io_setup2, u32, nr_events, u32, flags, + struct aio_sq_ring __user *, sq_ring, + struct aio_cq_ring __user *, cq_ring, + aio_context_t __user *, ctxp) { struct kioctx *ioctx; unsigned long ctx; long ret; - if (user1 || user2) - return -EINVAL; - if (flags & ~IOCTX_FLAG_IOPOLL) + if (flags & ~(IOCTX_FLAG_IOPOLL | IOCTX_FLAG_SCQRING)) return -EINVAL; ret = get_user(ctx, ctxp); @@ -1644,9 +1859,17 @@ SYSCALL_DEFINE5(io_setup2, u32, nr_events, u32, flags, void __user *, user1, if (IS_ERR(ioctx)) goto out; + if (flags & IOCTX_FLAG_SCQRING) { + ret = aio_scqring_map(ioctx, sq_ring, cq_ring); + if (ret) + goto err; + } + ret = put_user(ioctx->user_id, ctxp); - if (ret) + if (ret) { +err: kill_ioctx(current->mm, ioctx, NULL); + } percpu_ref_put(&ioctx->users); out: return ret; @@ -2323,8 +2546,7 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb, return -EINVAL; } - /* Poll IO doesn't need ring reservations */ - if (!(ctx->flags & IOCTX_FLAG_IOPOLL) && !get_reqs_available(ctx)) + if (aio_ctx_old_ring(ctx) && !get_reqs_available(ctx)) return -EAGAIN; ret = -EAGAIN; @@ -2413,7 +2635,7 @@ static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb, eventfd_ctx_put(req->ki_eventfd); iocb_put(req); out_put_reqs_available: - if (!(ctx->flags & IOCTX_FLAG_IOPOLL)) + if (aio_ctx_old_ring(ctx)) put_reqs_available(ctx, 1); return ret; } @@ -2473,6 +2695,211 @@ static void aio_submit_state_start(struct aio_submit_state *state, #endif } +static const struct iocb *aio_iocb_from_index(struct kioctx *ctx, unsigned idx) +{ + struct aio_mapped_range *range = &ctx->sq_ring.iocb_range; + const struct iocb *iocb; + + iocb = page_address(range->pages[idx >> iocb_page_shift]); + idx &= ((1 << iocb_page_shift) - 1); + return iocb + idx; +} + +static void aio_commit_sqring(struct kioctx *ctx, unsigned next_head) +{ + struct aio_sq_ring *ring = ctx->sq_ring.ring; + + if (ring->head != next_head) { + ring->head = next_head; + smp_wmb(); + } +} + +static const struct iocb *aio_peek_sqring(struct kioctx *ctx, unsigned *nhead) +{ + struct aio_mapped_range *range = &ctx->sq_ring.ring_range; + struct aio_sq_ring *ring = ctx->sq_ring.ring; + unsigned head, index; + u32 *array; + + smp_rmb(); + head = READ_ONCE(ring->head); + if (head == READ_ONCE(ring->tail)) + return NULL; + + *nhead = head + 1; + if (*nhead == ring->nr_events) + *nhead = 0; + + /* + * No guarantee the array is in the first page, so we can't just + * index ring->array. Find the map and offset from the head. + */ + head += offsetof(struct aio_sq_ring, array) >> 2; + array = page_address(range->pages[head >> array_page_shift]); + head &= ((1 << array_page_shift) - 1); + index = array[head]; + + if (index < ring->nr_events) + return aio_iocb_from_index(ctx, index); + + /* drop invalid entries */ + aio_commit_sqring(ctx, *nhead); + return NULL; +} + +static int aio_ring_submit(struct kioctx *ctx, unsigned int to_submit) +{ + struct aio_submit_state state, *statep = NULL; + int i, ret = 0, submit = 0; + + if (to_submit > AIO_PLUG_THRESHOLD) { + aio_submit_state_start(&state, ctx, to_submit); + statep = &state; + } + + for (i = 0; i < to_submit; i++) { + const struct iocb *iocb; + unsigned int next_head; + + iocb = aio_peek_sqring(ctx, &next_head); + if (!iocb) + break; + + ret = __io_submit_one(ctx, iocb, NULL, statep, false); + if (ret) + break; + + submit++; + aio_commit_sqring(ctx, next_head); + } + + if (statep) + aio_submit_state_end(statep); + + return submit ? submit : ret; +} + +/* + * 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. + */ +static int aio_cqring_wait(struct kioctx *ctx, int min_events) +{ + struct aio_cq_ring *ring = page_address(ctx->cq_ring.pages[0]); + DEFINE_WAIT(wait); + int ret = 0; + + smp_rmb(); + if (ring->head != ring->tail) + return 0; + if (!min_events) + return 0; + + do { + prepare_to_wait(&ctx->wait, &wait, TASK_INTERRUPTIBLE); + + ret = 0; + smp_rmb(); + if (ring->head != ring->tail) + break; + + schedule(); + + ret = -EINVAL; + if (atomic_read(&ctx->dead)) + break; + ret = -EINTR; + if (signal_pending(current)) + break; + } while (1); + + finish_wait(&ctx->wait, &wait); + return ret; +} + +static int __io_ring_enter(struct kioctx *ctx, unsigned int to_submit, + unsigned int min_complete, unsigned int flags) +{ + int ret = 0; + + if (flags & IORING_FLAG_SUBMIT) { + ret = aio_ring_submit(ctx, to_submit); + if (ret < 0) + return ret; + } + if (flags & IORING_FLAG_GETEVENTS) { + unsigned int nr_events = 0; + int get_ret; + + if (!ret && to_submit) + min_complete = 0; + + if (ctx->flags & IOCTX_FLAG_IOPOLL) + get_ret = __aio_iopoll_check(ctx, NULL, &nr_events, + min_complete, -1U); + else + get_ret = aio_cqring_wait(ctx, min_complete); + + if (get_ret < 0 && !ret) + ret = get_ret; + } + + return ret; +} + +/* sys_io_ring_enter: + * Alternative way to both submit and complete IO, instead of using + * io_submit(2) and io_getevents(2). Requires the use of the SQ/CQ + * ring interface, hence the io_context must be setup with + * io_setup2() and IOCTX_FLAG_SCQRING must be specified (and the + * sq_ring/cq_ring passed in). + * + * Returns the number of IOs submitted, if IORING_FLAG_SUBMIT + * is used, otherwise returns 0 for IORING_FLAG_GETEVENTS success, + * but not the number of events, as those will have to be found + * by the application by reading the CQ ring anyway. + * + * Apart from that, the error returns are much like io_submit() + * and io_getevents(), since a lot of the same error conditions + * are shared. + */ +SYSCALL_DEFINE4(io_ring_enter, aio_context_t, ctx_id, u32, to_submit, + u32, min_complete, u32, flags) +{ + struct kioctx *ctx; + long ret; + + ctx = lookup_ioctx(ctx_id); + if (!ctx) { + pr_debug("EINVAL: invalid context id\n"); + return -EINVAL; + } + + ret = -EBUSY; + if (!mutex_trylock(&ctx->getevents_lock)) + goto err; + + ret = -EOVERFLOW; + if (ctx->cq_ring_overflow) { + ctx->cq_ring_overflow = 0; + goto err_unlock; + } + + ret = -EINVAL; + if (unlikely(atomic_read(&ctx->dead))) + goto err_unlock; + + if (ctx->flags & IOCTX_FLAG_SCQRING) + ret = __io_ring_enter(ctx, to_submit, min_complete, flags); + +err_unlock: + mutex_unlock(&ctx->getevents_lock); +err: + percpu_ref_put(&ctx->users); + return ret; +} + /* sys_io_submit: * Queue the nr iocbs pointed to by iocbpp for processing. Returns * the number of iocbs queued. May return -EINVAL if the aio_context @@ -2502,6 +2929,10 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, return -EINVAL; } + /* SCQRING must use io_ring_enter() */ + if (ctx->flags & IOCTX_FLAG_SCQRING) + return -EINVAL; + if (nr > ctx->nr_events) nr = ctx->nr_events; @@ -2653,7 +3084,10 @@ static long do_io_getevents(aio_context_t ctx_id, long ret = -EINVAL; if (likely(ioctx)) { - if (likely(min_nr <= nr && min_nr >= 0)) { + /* SCQRING must use io_ring_enter() */ + if (ioctx->flags & IOCTX_FLAG_SCQRING) + ret = -EINVAL; + else if (min_nr <= nr && min_nr >= 0) { if (ioctx->flags & IOCTX_FLAG_IOPOLL) ret = aio_iopoll_check(ioctx, min_nr, nr, events); else diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 67b7f03aa9fc..e7bd364410c3 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -287,8 +287,10 @@ static inline void addr_limit_user_check(void) */ #ifndef CONFIG_ARCH_HAS_SYSCALL_WRAPPER asmlinkage long sys_io_setup(unsigned nr_reqs, aio_context_t __user *ctx); -asmlinkage long sys_io_setup2(unsigned, unsigned, void __user *, void __user *, +asmlinkage long sys_io_setup2(unsigned, unsigned, struct aio_cq_ring __user *, + struct aio_sq_ring __user *, aio_context_t __user *); +asmlinkage long sys_io_ring_enter(aio_context_t, unsigned, unsigned, unsigned); asmlinkage long sys_io_destroy(aio_context_t ctx); asmlinkage long sys_io_submit(aio_context_t, long, struct iocb __user * __user *); diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h index a6829bae9ada..5d3ada40ce15 100644 --- a/include/uapi/linux/aio_abi.h +++ b/include/uapi/linux/aio_abi.h @@ -109,6 +109,35 @@ struct iocb { }; /* 64 bytes */ #define IOCTX_FLAG_IOPOLL (1 << 0) /* io_context is polled */ +#define IOCTX_FLAG_SCQRING (1 << 1) /* Use SQ/CQ rings */ + +struct aio_sq_ring { + union { + struct { + u32 head; /* kernel consumer head */ + u32 tail; /* app producer tail */ + u32 nr_events; /* max events in ring */ + u64 iocbs; /* setup pointer to app iocbs */ + }; + u32 pad[16]; + }; + u32 array[0]; /* actual ring, index to iocbs */ +}; + +struct aio_cq_ring { + union { + struct { + u32 head; /* app consumer head */ + u32 tail; /* kernel producer tail */ + u32 nr_events; /* max events in ring */ + }; + struct io_event pad; + }; + struct io_event events[0]; /* ring, array of io_events */ +}; + +#define IORING_FLAG_SUBMIT (1 << 0) +#define IORING_FLAG_GETEVENTS (1 << 1) #undef IFBIG #undef IFLITTLE diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 17c8b4393669..a32b7ea93838 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -38,6 +38,7 @@ asmlinkage long sys_ni_syscall(void) COND_SYSCALL(io_setup); COND_SYSCALL(io_setup2); +COND_SYSCALL(io_ring_enter); COND_SYSCALL_COMPAT(io_setup); COND_SYSCALL(io_destroy); COND_SYSCALL(io_submit); -- 2.17.1
