From: Jens Axboe <axboe@kernel.dk> To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe <axboe@kernel.dk> Subject: [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Date: Mon, 14 Jan 2019 19:55:28 -0700 [thread overview] Message-ID: <20190115025531.13985-14-axboe@kernel.dk> (raw) In-Reply-To: <20190115025531.13985-1-axboe@kernel.dk> If we have fixed user buffers, we can map them into the kernel when we setup the io_context. That avoids the need to do get_user_pages() for each and every IO. To utilize this feature, the application must call io_uring_register() after having setup an io_uring context, passing in IORING_REGISTER_BUFFERS as the opcode, and the following struct as the argument: struct io_uring_register_buffers { struct iovec *iovecs; __u32 nr_iovecs; }; If successful, these buffers are now mapped into the kernel, eligible for IO. To use these fixed buffers, the application must use the IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len must point to somewhere inside the indexed buffer. The application may register buffers throughout the lifetime of the io_uring context. It can call io_uring_register() with IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of buffers, and then register a new set. The application need not unregister buffers explicitly before shutting down the io_uring context. It's perfectly valid to setup a larger buffer, and then sometimes only use parts of it for an IO. As long as the range is within the originally mapped region, it will work just fine. RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat arbitrary 1G per buffer size is also imposed. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/io_uring.c | 345 ++++++++++++++++++++++++- include/linux/sched/user.h | 2 +- include/linux/syscalls.h | 2 + include/uapi/linux/io_uring.h | 21 +- kernel/sys_ni.c | 1 + 7 files changed, 361 insertions(+), 12 deletions(-) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 194e79c0032e..7e89016f8118 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -400,3 +400,4 @@ 386 i386 rseq sys_rseq __ia32_sys_rseq 387 i386 io_uring_setup sys_io_uring_setup __ia32_compat_sys_io_uring_setup 388 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter +389 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 453ff7a79002..8e05d4f05d88 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -345,6 +345,7 @@ 334 common rseq __x64_sys_rseq 335 common io_uring_setup __x64_sys_io_uring_setup 336 common io_uring_enter __x64_sys_io_uring_enter +337 common io_uring_register __x64_sys_io_uring_register # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/io_uring.c b/fs/io_uring.c index d0e4e37592fe..00743a5a6fac 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -24,8 +24,11 @@ #include <linux/slab.h> #include <linux/workqueue.h> #include <linux/blkdev.h> +#include <linux/bvec.h> #include <linux/anon_inodes.h> #include <linux/sched/mm.h> +#include <linux/sizes.h> +#include <linux/nospec.h> #include <linux/uaccess.h> #include <linux/nospec.h> @@ -61,6 +64,13 @@ struct list_multi { unsigned multi; }; +struct io_mapped_ubuf { + u64 ubuf; + size_t len; + struct bio_vec *bvec; + unsigned int nr_bvecs; +}; + struct io_ring_ctx { struct percpu_ref refs; @@ -84,6 +94,11 @@ struct io_ring_ctx { struct mm_struct *sqo_mm; struct files_struct *sqo_files; + /* if used, fixed mapped user buffers */ + unsigned nr_user_bufs; + struct io_mapped_ubuf *user_bufs; + struct user_struct *user; + struct completion ctx_done; struct { @@ -691,12 +706,51 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) } } +static int io_import_fixed(struct io_ring_ctx *ctx, int rw, + const struct io_uring_sqe *sqe, + struct iov_iter *iter) +{ + struct io_mapped_ubuf *imu; + size_t len = sqe->len; + size_t offset; + int index; + + /* attempt to use fixed buffers without having provided iovecs */ + if (unlikely(!ctx->user_bufs)) + return -EFAULT; + if (unlikely(sqe->buf_index >= ctx->nr_user_bufs)) + return -EFAULT; + + index = array_index_nospec(sqe->buf_index, ctx->sq_entries); + imu = &ctx->user_bufs[index]; + if ((unsigned long) sqe->addr < imu->ubuf || + (unsigned long) sqe->addr + len > imu->ubuf + imu->len) + return -EFAULT; + + /* + * May not be a start of buffer, set size appropriately + * and advance us to the beginning. + */ + offset = (unsigned long) sqe->addr - imu->ubuf; + iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); + if (offset) + iov_iter_advance(iter, offset); + return 0; +} + static int io_import_iovec(struct io_ring_ctx *ctx, int rw, const struct io_uring_sqe *sqe, struct iovec **iovec, struct iov_iter *iter) { void __user *buf = (void __user *) (uintptr_t) sqe->addr; + if (sqe->opcode == IORING_OP_READ_FIXED || + sqe->opcode == IORING_OP_WRITE_FIXED) { + ssize_t ret = io_import_fixed(ctx, rw, sqe, iter); + *iovec = NULL; + return ret; + } + #ifdef CONFIG_COMPAT if (ctx->compat) return compat_import_iovec(rw, buf, sqe->len, UIO_FASTIOV, @@ -870,9 +924,19 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, ret = io_nop(req, sqe); break; case IORING_OP_READV: + if (unlikely(sqe->buf_index)) + return -EINVAL; ret = io_read(req, sqe, force_nonblock, state); break; case IORING_OP_WRITEV: + if (unlikely(sqe->buf_index)) + return -EINVAL; + ret = io_write(req, sqe, force_nonblock, state); + break; + case IORING_OP_READ_FIXED: + ret = io_read(req, sqe, force_nonblock, state); + break; + case IORING_OP_WRITE_FIXED: ret = io_write(req, sqe, force_nonblock, state); break; case IORING_OP_FSYNC: @@ -898,9 +962,11 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, static void io_sq_wq_submit_work(struct work_struct *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work.work); + struct sqe_submit *s = &req->work.submit; struct io_ring_ctx *ctx = req->ctx; - mm_segment_t old_fs = get_fs(); struct files_struct *old_files; + mm_segment_t old_fs; + bool needs_user; int ret; /* @@ -913,19 +979,32 @@ static void io_sq_wq_submit_work(struct work_struct *work) old_files = current->files; current->files = ctx->sqo_files; - if (!mmget_not_zero(ctx->sqo_mm)) { - ret = -EFAULT; - goto err; + /* + * If we're doing IO to fixed buffers, we don't need to get/set + * user context + */ + needs_user = true; + if (s->sqe->opcode == IORING_OP_READ_FIXED || + s->sqe->opcode == IORING_OP_WRITE_FIXED) + needs_user = false; + + if (needs_user) { + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + goto err; + } + use_mm(ctx->sqo_mm); + old_fs = get_fs(); + set_fs(USER_DS); } - use_mm(ctx->sqo_mm); - set_fs(USER_DS); - ret = __io_submit_sqe(ctx, req, &req->work.submit, false, NULL); - set_fs(old_fs); - unuse_mm(ctx->sqo_mm); - mmput(ctx->sqo_mm); + if (needs_user) { + set_fs(old_fs); + unuse_mm(ctx->sqo_mm); + mmput(ctx->sqo_mm); + } err: if (ret) { io_fill_cq_error(ctx, &req->work.submit, ret); @@ -1168,6 +1247,183 @@ static void io_sq_offload_stop(struct io_ring_ctx *ctx) } } +static int io_sqe_user_account_mem(struct io_ring_ctx *ctx, + unsigned long nr_pages) +{ + unsigned long page_limit, cur_pages, new_pages; + + if (!ctx->user) + return 0; + + /* Don't allow more pages than we can safely lock */ + page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + + do { + cur_pages = atomic_long_read(&ctx->user->locked_vm); + new_pages = cur_pages + nr_pages; + if (new_pages > page_limit) + return -ENOMEM; + } while (atomic_long_cmpxchg(&ctx->user->locked_vm, cur_pages, + new_pages) != cur_pages); + + return 0; +} + +static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) +{ + int i, j; + + if (!ctx->user_bufs) + return -EINVAL; + + for (i = 0; i < ctx->sq_entries; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + + for (j = 0; j < imu->nr_bvecs; j++) { + set_page_dirty_lock(imu->bvec[j].bv_page); + put_page(imu->bvec[j].bv_page); + } + + if (ctx->user) + atomic_long_sub(imu->nr_bvecs, &ctx->user->locked_vm); + kfree(imu->bvec); + imu->nr_bvecs = 0; + } + + kfree(ctx->user_bufs); + ctx->user_bufs = NULL; + free_uid(ctx->user); + ctx->user = NULL; + return 0; +} + +static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, + struct io_uring_register_buffers *reg, unsigned index) +{ + struct iovec __user *src; + +#ifdef CONFIG_COMPAT + if (ctx->compat) { + struct compat_iovec __user *ciovs; + struct compat_iovec ciov; + + ciovs = (struct compat_iovec __user *) reg->iovecs; + if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) + return -EFAULT; + + dst->iov_base = (void __user *) (unsigned long) ciov.iov_base; + dst->iov_len = ciov.iov_len; + return 0; + } +#endif + src = (struct iovec __user *) ®->iovecs[index]; + if (copy_from_user(dst, src, sizeof(*dst))) + return -EFAULT; + return 0; +} + +static int io_sqe_buffer_register(struct io_ring_ctx *ctx, + struct io_uring_register_buffers *reg) +{ + struct page **pages = NULL; + int i, j, got_pages = 0; + int ret = -EINVAL; + + if (reg->nr_iovecs > USHRT_MAX) + return -EINVAL; + + ctx->user_bufs = kcalloc(reg->nr_iovecs, sizeof(struct io_mapped_ubuf), + GFP_KERNEL); + if (!ctx->user_bufs) + return -ENOMEM; + + if (!capable(CAP_IPC_LOCK)) + ctx->user = get_uid(current_user()); + + for (i = 0; i < reg->nr_iovecs; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + unsigned long off, start, end, ubuf; + int pret, nr_pages; + struct iovec iov; + size_t size; + + ret = io_copy_iov(ctx, &iov, reg, i); + if (ret) + break; + + /* + * Don't impose further limits on the size and buffer + * constraints here, we'll -EINVAL later when IO is + * submitted if they are wrong. + */ + ret = -EFAULT; + if (!iov.iov_base) + goto err; + + /* arbitrary limit, but we need something */ + if (iov.iov_len > SZ_1G) + goto err; + + ubuf = (unsigned long) iov.iov_base; + end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; + start = ubuf >> PAGE_SHIFT; + nr_pages = end - start; + + ret = io_sqe_user_account_mem(ctx, nr_pages); + if (ret) + goto err; + + if (!pages || nr_pages > got_pages) { + kfree(pages); + pages = kmalloc_array(nr_pages, sizeof(struct page *), + GFP_KERNEL); + if (!pages) + goto err; + got_pages = nr_pages; + } + + imu->bvec = kmalloc_array(nr_pages, sizeof(struct bio_vec), + GFP_KERNEL); + if (!imu->bvec) + goto err; + + down_write(¤t->mm->mmap_sem); + pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE, + pages, NULL); + up_write(¤t->mm->mmap_sem); + + if (pret < nr_pages) { + if (pret < 0) + ret = pret; + goto err; + } + + off = ubuf & ~PAGE_MASK; + size = iov.iov_len; + for (j = 0; j < nr_pages; j++) { + size_t vec_len; + + vec_len = min_t(size_t, size, PAGE_SIZE - off); + imu->bvec[j].bv_page = pages[j]; + imu->bvec[j].bv_len = vec_len; + imu->bvec[j].bv_offset = off; + off = 0; + size -= vec_len; + } + /* store original address for later verification */ + imu->ubuf = ubuf; + imu->len = iov.iov_len; + imu->nr_bvecs = nr_pages; + } + kfree(pages); + ctx->nr_user_bufs = reg->nr_iovecs; + return 0; +err: + kfree(pages); + io_sqe_buffer_unregister(ctx); + return ret; +} + static void io_free_scq_urings(struct io_ring_ctx *ctx) { if (ctx->sq_ring) { @@ -1189,6 +1445,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) io_sq_offload_stop(ctx); io_iopoll_reap_events(ctx); io_free_scq_urings(ctx); + io_sqe_buffer_unregister(ctx); percpu_ref_exit(&ctx->refs); kfree(ctx); } @@ -1436,6 +1693,74 @@ COMPAT_SYSCALL_DEFINE2(io_uring_setup, u32, entries, } #endif +static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, + void __user *arg) +{ + int ret; + + /* Drop our initial ref and wait for the ctx to be fully idle */ + percpu_ref_put(&ctx->refs); + percpu_ref_kill(&ctx->refs); + wait_for_completion(&ctx->ctx_done); + + switch (opcode) { + case IORING_REGISTER_BUFFERS: { + struct io_uring_register_buffers reg; + + ret = -EFAULT; + if (copy_from_user(®, arg, sizeof(reg))) + break; + ret = io_sqe_buffer_register(ctx, ®); + break; + } + case IORING_UNREGISTER_BUFFERS: + ret = -EINVAL; + if (arg) + break; + ret = io_sqe_buffer_unregister(ctx); + break; + default: + ret = -EINVAL; + break; + } + + /* bring the ctx back to life */ + percpu_ref_resurrect(&ctx->refs); + percpu_ref_get(&ctx->refs); + return ret; +} + +SYSCALL_DEFINE3(io_uring_register, unsigned int, fd, unsigned int, opcode, + void __user *, arg) +{ + struct io_ring_ctx *ctx; + long ret = -EBADF; + struct fd f; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -EOPNOTSUPP; + if (f.file->f_op != &io_uring_fops) + goto out_fput; + + ret = -EINVAL; + ctx = f.file->private_data; + if (!percpu_ref_tryget(&ctx->refs)) + goto out_fput; + + ret = -EBUSY; + if (mutex_trylock(&ctx->uring_lock)) { + ret = __io_uring_register(ctx, opcode, arg); + mutex_unlock(&ctx->uring_lock); + } + io_ring_drop_ctx_refs(ctx, 1); +out_fput: + fdput(f); + return ret; +} + static int __init io_uring_init(void) { req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index 39ad98c09c58..c7b5f86b91a1 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -40,7 +40,7 @@ struct user_struct { kuid_t uid; #if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \ - defined(CONFIG_NET) + defined(CONFIG_NET) || defined(CONFIG_IO_URING) atomic_long_t locked_vm; #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 542757a4c898..e36c264d74e8 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -314,6 +314,8 @@ asmlinkage long sys_io_uring_setup(u32 entries, struct io_uring_params __user *p); asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, u32 min_complete, u32 flags); +asmlinkage long sys_io_uring_register(unsigned int fd, unsigned op, + void __user *arg); /* fs/xattr.c */ asmlinkage long sys_setxattr(const char __user *path, const char __user *name, diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index d31ae2f767d1..fda25d09c8a1 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -30,7 +30,10 @@ struct io_uring_sqe { __u32 fsync_flags; }; __u64 user_data; /* data to be passed back at completion time */ - __u64 __pad2[3]; + union { + __u16 buf_index; /* index into fixed buffers, if used */ + __u64 __pad2[3]; + }; }; /* @@ -42,6 +45,8 @@ struct io_uring_sqe { #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 #define IORING_OP_FSYNC 3 +#define IORING_OP_READ_FIXED 4 +#define IORING_OP_WRITE_FIXED 5 /* * sqe->fsync_flags @@ -105,4 +110,18 @@ struct io_uring_params { struct io_cqring_offsets cq_off; }; +/* + * io_uring_register(2) opcodes and arguments + */ +#define IORING_REGISTER_BUFFERS 0 +#define IORING_UNREGISTER_BUFFERS 1 + +struct io_uring_register_buffers { + union { + struct iovec *iovecs; + __u64 pad; + }; + __u32 nr_iovecs; +}; + #endif diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index ee5e523564bb..1bb6604dc19f 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -48,6 +48,7 @@ COND_SYSCALL_COMPAT(io_getevents); COND_SYSCALL_COMPAT(io_pgetevents); COND_SYSCALL(io_uring_setup); COND_SYSCALL(io_uring_enter); +COND_SYSCALL(io_uring_register); /* fs/xattr.c */ -- 2.17.1
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@kernel.dk> To: linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-block@vger.kernel.org, linux-arch@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe <axboe@kernel.dk> Subject: [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Date: Mon, 14 Jan 2019 19:55:28 -0700 [thread overview] Message-ID: <20190115025531.13985-14-axboe@kernel.dk> (raw) In-Reply-To: <20190115025531.13985-1-axboe@kernel.dk> If we have fixed user buffers, we can map them into the kernel when we setup the io_context. That avoids the need to do get_user_pages() for each and every IO. To utilize this feature, the application must call io_uring_register() after having setup an io_uring context, passing in IORING_REGISTER_BUFFERS as the opcode, and the following struct as the argument: struct io_uring_register_buffers { struct iovec *iovecs; __u32 nr_iovecs; }; If successful, these buffers are now mapped into the kernel, eligible for IO. To use these fixed buffers, the application must use the IORING_OP_READ_FIXED and IORING_OP_WRITE_FIXED opcodes, and then set sqe->index to the desired buffer index. sqe->addr..sqe->addr+seq->len must point to somewhere inside the indexed buffer. The application may register buffers throughout the lifetime of the io_uring context. It can call io_uring_register() with IORING_UNREGISTER_BUFFERS as the opcode to unregister the current set of buffers, and then register a new set. The application need not unregister buffers explicitly before shutting down the io_uring context. It's perfectly valid to setup a larger buffer, and then sometimes only use parts of it for an IO. As long as the range is within the originally mapped region, it will work just fine. RLIMIT_MEMLOCK is used to check how much memory we can pin. A somewhat arbitrary 1G per buffer size is also imposed. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/io_uring.c | 345 ++++++++++++++++++++++++- include/linux/sched/user.h | 2 +- include/linux/syscalls.h | 2 + include/uapi/linux/io_uring.h | 21 +- kernel/sys_ni.c | 1 + 7 files changed, 361 insertions(+), 12 deletions(-) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 194e79c0032e..7e89016f8118 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -400,3 +400,4 @@ 386 i386 rseq sys_rseq __ia32_sys_rseq 387 i386 io_uring_setup sys_io_uring_setup __ia32_compat_sys_io_uring_setup 388 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter +389 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 453ff7a79002..8e05d4f05d88 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -345,6 +345,7 @@ 334 common rseq __x64_sys_rseq 335 common io_uring_setup __x64_sys_io_uring_setup 336 common io_uring_enter __x64_sys_io_uring_enter +337 common io_uring_register __x64_sys_io_uring_register # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/fs/io_uring.c b/fs/io_uring.c index d0e4e37592fe..00743a5a6fac 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -24,8 +24,11 @@ #include <linux/slab.h> #include <linux/workqueue.h> #include <linux/blkdev.h> +#include <linux/bvec.h> #include <linux/anon_inodes.h> #include <linux/sched/mm.h> +#include <linux/sizes.h> +#include <linux/nospec.h> #include <linux/uaccess.h> #include <linux/nospec.h> @@ -61,6 +64,13 @@ struct list_multi { unsigned multi; }; +struct io_mapped_ubuf { + u64 ubuf; + size_t len; + struct bio_vec *bvec; + unsigned int nr_bvecs; +}; + struct io_ring_ctx { struct percpu_ref refs; @@ -84,6 +94,11 @@ struct io_ring_ctx { struct mm_struct *sqo_mm; struct files_struct *sqo_files; + /* if used, fixed mapped user buffers */ + unsigned nr_user_bufs; + struct io_mapped_ubuf *user_bufs; + struct user_struct *user; + struct completion ctx_done; struct { @@ -691,12 +706,51 @@ static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) } } +static int io_import_fixed(struct io_ring_ctx *ctx, int rw, + const struct io_uring_sqe *sqe, + struct iov_iter *iter) +{ + struct io_mapped_ubuf *imu; + size_t len = sqe->len; + size_t offset; + int index; + + /* attempt to use fixed buffers without having provided iovecs */ + if (unlikely(!ctx->user_bufs)) + return -EFAULT; + if (unlikely(sqe->buf_index >= ctx->nr_user_bufs)) + return -EFAULT; + + index = array_index_nospec(sqe->buf_index, ctx->sq_entries); + imu = &ctx->user_bufs[index]; + if ((unsigned long) sqe->addr < imu->ubuf || + (unsigned long) sqe->addr + len > imu->ubuf + imu->len) + return -EFAULT; + + /* + * May not be a start of buffer, set size appropriately + * and advance us to the beginning. + */ + offset = (unsigned long) sqe->addr - imu->ubuf; + iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); + if (offset) + iov_iter_advance(iter, offset); + return 0; +} + static int io_import_iovec(struct io_ring_ctx *ctx, int rw, const struct io_uring_sqe *sqe, struct iovec **iovec, struct iov_iter *iter) { void __user *buf = (void __user *) (uintptr_t) sqe->addr; + if (sqe->opcode == IORING_OP_READ_FIXED || + sqe->opcode == IORING_OP_WRITE_FIXED) { + ssize_t ret = io_import_fixed(ctx, rw, sqe, iter); + *iovec = NULL; + return ret; + } + #ifdef CONFIG_COMPAT if (ctx->compat) return compat_import_iovec(rw, buf, sqe->len, UIO_FASTIOV, @@ -870,9 +924,19 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, ret = io_nop(req, sqe); break; case IORING_OP_READV: + if (unlikely(sqe->buf_index)) + return -EINVAL; ret = io_read(req, sqe, force_nonblock, state); break; case IORING_OP_WRITEV: + if (unlikely(sqe->buf_index)) + return -EINVAL; + ret = io_write(req, sqe, force_nonblock, state); + break; + case IORING_OP_READ_FIXED: + ret = io_read(req, sqe, force_nonblock, state); + break; + case IORING_OP_WRITE_FIXED: ret = io_write(req, sqe, force_nonblock, state); break; case IORING_OP_FSYNC: @@ -898,9 +962,11 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, static void io_sq_wq_submit_work(struct work_struct *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work.work); + struct sqe_submit *s = &req->work.submit; struct io_ring_ctx *ctx = req->ctx; - mm_segment_t old_fs = get_fs(); struct files_struct *old_files; + mm_segment_t old_fs; + bool needs_user; int ret; /* @@ -913,19 +979,32 @@ static void io_sq_wq_submit_work(struct work_struct *work) old_files = current->files; current->files = ctx->sqo_files; - if (!mmget_not_zero(ctx->sqo_mm)) { - ret = -EFAULT; - goto err; + /* + * If we're doing IO to fixed buffers, we don't need to get/set + * user context + */ + needs_user = true; + if (s->sqe->opcode == IORING_OP_READ_FIXED || + s->sqe->opcode == IORING_OP_WRITE_FIXED) + needs_user = false; + + if (needs_user) { + if (!mmget_not_zero(ctx->sqo_mm)) { + ret = -EFAULT; + goto err; + } + use_mm(ctx->sqo_mm); + old_fs = get_fs(); + set_fs(USER_DS); } - use_mm(ctx->sqo_mm); - set_fs(USER_DS); - ret = __io_submit_sqe(ctx, req, &req->work.submit, false, NULL); - set_fs(old_fs); - unuse_mm(ctx->sqo_mm); - mmput(ctx->sqo_mm); + if (needs_user) { + set_fs(old_fs); + unuse_mm(ctx->sqo_mm); + mmput(ctx->sqo_mm); + } err: if (ret) { io_fill_cq_error(ctx, &req->work.submit, ret); @@ -1168,6 +1247,183 @@ static void io_sq_offload_stop(struct io_ring_ctx *ctx) } } +static int io_sqe_user_account_mem(struct io_ring_ctx *ctx, + unsigned long nr_pages) +{ + unsigned long page_limit, cur_pages, new_pages; + + if (!ctx->user) + return 0; + + /* Don't allow more pages than we can safely lock */ + page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + + do { + cur_pages = atomic_long_read(&ctx->user->locked_vm); + new_pages = cur_pages + nr_pages; + if (new_pages > page_limit) + return -ENOMEM; + } while (atomic_long_cmpxchg(&ctx->user->locked_vm, cur_pages, + new_pages) != cur_pages); + + return 0; +} + +static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) +{ + int i, j; + + if (!ctx->user_bufs) + return -EINVAL; + + for (i = 0; i < ctx->sq_entries; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + + for (j = 0; j < imu->nr_bvecs; j++) { + set_page_dirty_lock(imu->bvec[j].bv_page); + put_page(imu->bvec[j].bv_page); + } + + if (ctx->user) + atomic_long_sub(imu->nr_bvecs, &ctx->user->locked_vm); + kfree(imu->bvec); + imu->nr_bvecs = 0; + } + + kfree(ctx->user_bufs); + ctx->user_bufs = NULL; + free_uid(ctx->user); + ctx->user = NULL; + return 0; +} + +static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, + struct io_uring_register_buffers *reg, unsigned index) +{ + struct iovec __user *src; + +#ifdef CONFIG_COMPAT + if (ctx->compat) { + struct compat_iovec __user *ciovs; + struct compat_iovec ciov; + + ciovs = (struct compat_iovec __user *) reg->iovecs; + if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) + return -EFAULT; + + dst->iov_base = (void __user *) (unsigned long) ciov.iov_base; + dst->iov_len = ciov.iov_len; + return 0; + } +#endif + src = (struct iovec __user *) ®->iovecs[index]; + if (copy_from_user(dst, src, sizeof(*dst))) + return -EFAULT; + return 0; +} + +static int io_sqe_buffer_register(struct io_ring_ctx *ctx, + struct io_uring_register_buffers *reg) +{ + struct page **pages = NULL; + int i, j, got_pages = 0; + int ret = -EINVAL; + + if (reg->nr_iovecs > USHRT_MAX) + return -EINVAL; + + ctx->user_bufs = kcalloc(reg->nr_iovecs, sizeof(struct io_mapped_ubuf), + GFP_KERNEL); + if (!ctx->user_bufs) + return -ENOMEM; + + if (!capable(CAP_IPC_LOCK)) + ctx->user = get_uid(current_user()); + + for (i = 0; i < reg->nr_iovecs; i++) { + struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; + unsigned long off, start, end, ubuf; + int pret, nr_pages; + struct iovec iov; + size_t size; + + ret = io_copy_iov(ctx, &iov, reg, i); + if (ret) + break; + + /* + * Don't impose further limits on the size and buffer + * constraints here, we'll -EINVAL later when IO is + * submitted if they are wrong. + */ + ret = -EFAULT; + if (!iov.iov_base) + goto err; + + /* arbitrary limit, but we need something */ + if (iov.iov_len > SZ_1G) + goto err; + + ubuf = (unsigned long) iov.iov_base; + end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; + start = ubuf >> PAGE_SHIFT; + nr_pages = end - start; + + ret = io_sqe_user_account_mem(ctx, nr_pages); + if (ret) + goto err; + + if (!pages || nr_pages > got_pages) { + kfree(pages); + pages = kmalloc_array(nr_pages, sizeof(struct page *), + GFP_KERNEL); + if (!pages) + goto err; + got_pages = nr_pages; + } + + imu->bvec = kmalloc_array(nr_pages, sizeof(struct bio_vec), + GFP_KERNEL); + if (!imu->bvec) + goto err; + + down_write(¤t->mm->mmap_sem); + pret = get_user_pages_longterm(ubuf, nr_pages, FOLL_WRITE, + pages, NULL); + up_write(¤t->mm->mmap_sem); + + if (pret < nr_pages) { + if (pret < 0) + ret = pret; + goto err; + } + + off = ubuf & ~PAGE_MASK; + size = iov.iov_len; + for (j = 0; j < nr_pages; j++) { + size_t vec_len; + + vec_len = min_t(size_t, size, PAGE_SIZE - off); + imu->bvec[j].bv_page = pages[j]; + imu->bvec[j].bv_len = vec_len; + imu->bvec[j].bv_offset = off; + off = 0; + size -= vec_len; + } + /* store original address for later verification */ + imu->ubuf = ubuf; + imu->len = iov.iov_len; + imu->nr_bvecs = nr_pages; + } + kfree(pages); + ctx->nr_user_bufs = reg->nr_iovecs; + return 0; +err: + kfree(pages); + io_sqe_buffer_unregister(ctx); + return ret; +} + static void io_free_scq_urings(struct io_ring_ctx *ctx) { if (ctx->sq_ring) { @@ -1189,6 +1445,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx) io_sq_offload_stop(ctx); io_iopoll_reap_events(ctx); io_free_scq_urings(ctx); + io_sqe_buffer_unregister(ctx); percpu_ref_exit(&ctx->refs); kfree(ctx); } @@ -1436,6 +1693,74 @@ COMPAT_SYSCALL_DEFINE2(io_uring_setup, u32, entries, } #endif +static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, + void __user *arg) +{ + int ret; + + /* Drop our initial ref and wait for the ctx to be fully idle */ + percpu_ref_put(&ctx->refs); + percpu_ref_kill(&ctx->refs); + wait_for_completion(&ctx->ctx_done); + + switch (opcode) { + case IORING_REGISTER_BUFFERS: { + struct io_uring_register_buffers reg; + + ret = -EFAULT; + if (copy_from_user(®, arg, sizeof(reg))) + break; + ret = io_sqe_buffer_register(ctx, ®); + break; + } + case IORING_UNREGISTER_BUFFERS: + ret = -EINVAL; + if (arg) + break; + ret = io_sqe_buffer_unregister(ctx); + break; + default: + ret = -EINVAL; + break; + } + + /* bring the ctx back to life */ + percpu_ref_resurrect(&ctx->refs); + percpu_ref_get(&ctx->refs); + return ret; +} + +SYSCALL_DEFINE3(io_uring_register, unsigned int, fd, unsigned int, opcode, + void __user *, arg) +{ + struct io_ring_ctx *ctx; + long ret = -EBADF; + struct fd f; + + f = fdget(fd); + if (!f.file) + return -EBADF; + + ret = -EOPNOTSUPP; + if (f.file->f_op != &io_uring_fops) + goto out_fput; + + ret = -EINVAL; + ctx = f.file->private_data; + if (!percpu_ref_tryget(&ctx->refs)) + goto out_fput; + + ret = -EBUSY; + if (mutex_trylock(&ctx->uring_lock)) { + ret = __io_uring_register(ctx, opcode, arg); + mutex_unlock(&ctx->uring_lock); + } + io_ring_drop_ctx_refs(ctx, 1); +out_fput: + fdput(f); + return ret; +} + static int __init io_uring_init(void) { req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h index 39ad98c09c58..c7b5f86b91a1 100644 --- a/include/linux/sched/user.h +++ b/include/linux/sched/user.h @@ -40,7 +40,7 @@ struct user_struct { kuid_t uid; #if defined(CONFIG_PERF_EVENTS) || defined(CONFIG_BPF_SYSCALL) || \ - defined(CONFIG_NET) + defined(CONFIG_NET) || defined(CONFIG_IO_URING) atomic_long_t locked_vm; #endif diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 542757a4c898..e36c264d74e8 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -314,6 +314,8 @@ asmlinkage long sys_io_uring_setup(u32 entries, struct io_uring_params __user *p); asmlinkage long sys_io_uring_enter(unsigned int fd, u32 to_submit, u32 min_complete, u32 flags); +asmlinkage long sys_io_uring_register(unsigned int fd, unsigned op, + void __user *arg); /* fs/xattr.c */ asmlinkage long sys_setxattr(const char __user *path, const char __user *name, diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index d31ae2f767d1..fda25d09c8a1 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -30,7 +30,10 @@ struct io_uring_sqe { __u32 fsync_flags; }; __u64 user_data; /* data to be passed back at completion time */ - __u64 __pad2[3]; + union { + __u16 buf_index; /* index into fixed buffers, if used */ + __u64 __pad2[3]; + }; }; /* @@ -42,6 +45,8 @@ struct io_uring_sqe { #define IORING_OP_READV 1 #define IORING_OP_WRITEV 2 #define IORING_OP_FSYNC 3 +#define IORING_OP_READ_FIXED 4 +#define IORING_OP_WRITE_FIXED 5 /* * sqe->fsync_flags @@ -105,4 +110,18 @@ struct io_uring_params { struct io_cqring_offsets cq_off; }; +/* + * io_uring_register(2) opcodes and arguments + */ +#define IORING_REGISTER_BUFFERS 0 +#define IORING_UNREGISTER_BUFFERS 1 + +struct io_uring_register_buffers { + union { + struct iovec *iovecs; + __u64 pad; + }; + __u32 nr_iovecs; +}; + #endif diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index ee5e523564bb..1bb6604dc19f 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -48,6 +48,7 @@ COND_SYSCALL_COMPAT(io_getevents); COND_SYSCALL_COMPAT(io_pgetevents); COND_SYSCALL(io_uring_setup); COND_SYSCALL(io_uring_enter); +COND_SYSCALL(io_uring_register); /* fs/xattr.c */ -- 2.17.1 -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>
next prev parent reply other threads:[~2019-01-15 2:56 UTC|newest] Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-15 2:55 (unknown), Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 01/16] fs: add an iopoll method to struct file_operations Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 02/16] block: wire up block device iopoll method Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 03/16] block: add bio_set_polled() helper Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 04/16] iomap: wire up the iopoll method Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 05/16] Add io_uring IO interface Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 16:51 ` Jonathan Corbet 2019-01-15 16:51 ` Jonathan Corbet 2019-01-15 16:55 ` Jens Axboe 2019-01-15 16:55 ` Jens Axboe 2019-01-15 17:26 ` Jens Axboe 2019-01-15 17:26 ` Jens Axboe 2019-01-16 10:41 ` Arnd Bergmann 2019-01-16 10:41 ` Arnd Bergmann 2019-01-16 11:00 ` Arnd Bergmann 2019-01-16 11:00 ` Arnd Bergmann 2019-01-16 15:12 ` Jens Axboe 2019-01-16 15:12 ` Jens Axboe 2019-01-16 15:16 ` Arnd Bergmann 2019-01-16 15:16 ` Arnd Bergmann 2019-01-16 15:25 ` Jens Axboe 2019-01-16 15:25 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 06/16] io_uring: add fsync support Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 07/16] io_uring: support for IO polling Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 08/16] io_uring: add submission side request cache Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 09/16] fs: add fget_many() and fput_many() Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 10/16] io_uring: use fget/fput_many() for file references Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 11/16] io_uring: batch io_kiocb allocation Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 12/16] block: implement bio helper to add iter bvec pages to bio Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` Jens Axboe [this message] 2019-01-15 2:55 ` [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Jens Axboe 2019-01-16 10:53 ` Arnd Bergmann 2019-01-16 15:14 ` Jens Axboe 2019-01-16 15:14 ` Jens Axboe 2019-01-16 15:32 ` Jens Axboe 2019-01-16 15:32 ` Jens Axboe 2019-01-16 15:41 ` Arnd Bergmann 2019-01-16 15:47 ` Jens Axboe 2019-01-16 15:47 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 14/16] io_uring: add submission polling Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 15/16] io_uring: add file registration Jens Axboe 2019-01-15 2:55 ` Jens Axboe 2019-01-16 10:45 ` Arnd Bergmann 2019-01-16 10:45 ` Arnd Bergmann 2019-01-16 15:15 ` Jens Axboe 2019-01-16 15:15 ` Jens Axboe 2019-01-15 2:55 ` [PATCH 16/16] io_uring: add io_uring_event cache hit information Jens Axboe 2019-01-15 2:55 ` Jens Axboe -- strict thread matches above, loose matches on Subject: below -- 2019-01-12 21:29 [PATCHSET v3] io_uring IO interface Jens Axboe 2019-01-12 21:30 ` [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Jens Axboe 2019-01-12 21:30 ` Jens Axboe 2019-01-08 16:56 [PATCHSET v1] io_uring IO interface Jens Axboe 2019-01-08 16:56 ` [PATCH 13/16] io_uring: add support for pre-mapped user IO buffers Jens Axboe 2019-01-08 16:56 ` Jens Axboe 2019-01-09 12:16 ` Christoph Hellwig 2019-01-09 17:06 ` Jens Axboe 2019-01-09 17:06 ` Jens Axboe
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20190115025531.13985-14-axboe@kernel.dk \ --to=axboe@kernel.dk \ --cc=avi@scylladb.com \ --cc=hch@lst.de \ --cc=jmoyer@redhat.com \ --cc=linux-aio@kvack.org \ --cc=linux-arch@vger.kernel.org \ --cc=linux-block@vger.kernel.org \ --cc=linux-fsdevel@vger.kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.