[RFC 05/10] io_uring/rsrc: introduce buf registration structure
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2026-07-11 10:49:26
Also in:
io-uring
Subsystem:
io_uring, the rest · Maintainers:
Jens Axboe, Linus Torvalds
In preparation to following changes, instead of passing an iovec for buffer registration introduce a new structure. It'll be moved to uapi later, but for now it's initialised early from a user provided iovec. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- io_uring/rsrc.c | 47 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 15 deletions(-)
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 8d0f2ee24e0c..8af371ba6c06 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c@@ -27,8 +27,13 @@ struct io_rsrc_update { u32 offset; }; +struct io_uring_regbuf_desc { + __u64 uaddr; + __u64 size; +}; + static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, - struct iovec *iov); + struct io_uring_regbuf_desc *desc); static int hpage_acct_ref(struct io_ring_ctx *ctx, struct page *hpage, bool *acct_new)
@@ -81,6 +86,15 @@ static bool hpage_acct_unref(struct io_ring_ctx *ctx, struct page *hpage) #define IO_CACHED_BVECS_SEGS 32 +static void io_iov_to_regbuf_desc(const struct iovec *iov, + struct io_uring_regbuf_desc *desc) +{ + *desc = (struct io_uring_regbuf_desc) { + .uaddr = (u64)(uintptr_t)iov->iov_base, + .size = iov->iov_len, + }; +} + int __io_account_mem(struct user_struct *user, unsigned long nr_pages) { unsigned long page_limit, cur_pages, new_pages;
@@ -381,6 +395,7 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, return -EINVAL; for (done = 0; done < nr_args; done++) { + struct io_uring_regbuf_desc desc; struct io_rsrc_node *node; u64 tag = 0;
@@ -394,7 +409,9 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, err = -EFAULT; break; } - node = io_sqe_buffer_register(ctx, iov); + + io_iov_to_regbuf_desc(iov, &desc); + node = io_sqe_buffer_register(ctx, &desc); if (IS_ERR(node)) { err = PTR_ERR(node); break;
@@ -853,26 +870,26 @@ bool io_check_coalesce_buffer(struct page **page_array, int nr_pages, } static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, - struct iovec *iov) + struct io_uring_regbuf_desc *desc) { + unsigned long uaddr = (unsigned long)desc->uaddr; + size_t size = desc->size; struct io_mapped_ubuf *imu = NULL; struct page **pages = NULL; struct io_rsrc_node *node; unsigned long off; - size_t size; int ret, nr_pages, i; struct io_imu_folio_data data; bool coalesced = false; - if (!iov->iov_base) { - if (iov->iov_len) + if (!uaddr) { + if (size) return ERR_PTR(-EFAULT); /* remove the buffer without installing a new one */ return NULL; } - ret = io_validate_user_buf_range((unsigned long)iov->iov_base, - iov->iov_len); + ret = io_validate_user_buf_range(uaddr, size); if (ret) return ERR_PTR(ret);
@@ -881,8 +898,7 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, return ERR_PTR(-ENOMEM); ret = -ENOMEM; - pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len, - &nr_pages); + pages = io_pin_pages(uaddr, size, &nr_pages); if (IS_ERR(pages)) { ret = PTR_ERR(pages); pages = NULL;
@@ -904,10 +920,9 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, if (ret) goto done; - size = iov->iov_len; /* store original address for later verification */ - imu->ubuf = (unsigned long) iov->iov_base; - imu->len = iov->iov_len; + imu->ubuf = uaddr; + imu->len = size; imu->folio_shift = PAGE_SHIFT; imu->release = io_release_ubuf; imu->priv = imu;
@@ -917,7 +932,7 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx, imu->folio_shift = data.folio_shift; refcount_set(&imu->refs, 1); - off = (unsigned long)iov->iov_base & ~PAGE_MASK; + off = uaddr & ~PAGE_MASK; if (coalesced) off += data.first_folio_page_idx << PAGE_SHIFT;
@@ -969,6 +984,7 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, memset(iov, 0, sizeof(*iov)); for (i = 0; i < nr_args; i++) { + struct io_uring_regbuf_desc desc; struct io_rsrc_node *node; u64 tag = 0;
@@ -992,7 +1008,8 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, } } - node = io_sqe_buffer_register(ctx, iov); + io_iov_to_regbuf_desc(iov, &desc); + node = io_sqe_buffer_register(ctx, &desc); if (IS_ERR(node)) { ret = PTR_ERR(node); break;
--
2.54.0