From: Pavel Begunkov <asml.silence@gmail.com>
To: io-uring@vger.kernel.org
Cc: asml.silence@gmail.com
Subject: [PATCH 5/7] io_uring: keep ring laoyut in a structure
Date: Wed, 12 Nov 2025 12:45:57 +0000 [thread overview]
Message-ID: <9033e77c3fc31f2c82efdf1fbf57b7549ea2b934.1762947814.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1762947814.git.asml.silence@gmail.com>
Add a structure keeping SQ/CQ sizes and offsets. For now it only records
data previously returned from rings_size and the SQ size.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
io_uring/io_uring.c | 54 +++++++++++++++++++++++----------------------
io_uring/io_uring.h | 12 ++++++++--
io_uring/register.c | 24 ++++++--------------
3 files changed, 45 insertions(+), 45 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index f039e293582a..1dfd0a8a7270 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2757,47 +2757,57 @@ static void io_rings_free(struct io_ring_ctx *ctx)
ctx->sq_sqes = NULL;
}
-unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
- unsigned int cq_entries, size_t *sq_offset)
+int rings_size(unsigned int flags, unsigned int sq_entries,
+ unsigned int cq_entries, struct io_rings_layout *rl)
{
struct io_rings *rings;
+ size_t sqe_size;
size_t off;
- *sq_offset = SIZE_MAX;
-
if (flags & IORING_SETUP_CQE_MIXED) {
if (cq_entries < 2)
- return SIZE_MAX;
+ return -EOVERFLOW;
}
if (flags & IORING_SETUP_SQE_MIXED) {
if (sq_entries < 2)
- return SIZE_MAX;
+ return -EOVERFLOW;
}
+ rl->sq_array_offset = SIZE_MAX;
+
+ sqe_size = sizeof(struct io_uring_sqe);
+ if (flags & IORING_SETUP_SQE128)
+ sqe_size *= 2;
+
+ rl->sq_size = array_size(sqe_size, sq_entries);
+ if (rl->sq_size == SIZE_MAX)
+ return -EOVERFLOW;
+
off = struct_size(rings, cqes, cq_entries);
if (flags & IORING_SETUP_CQE32)
off = size_mul(off, 2);
if (off == SIZE_MAX)
- return SIZE_MAX;
+ return -EOVERFLOW;
#ifdef CONFIG_SMP
off = ALIGN(off, SMP_CACHE_BYTES);
if (off == 0)
- return SIZE_MAX;
+ return -EOVERFLOW;
#endif
if (!(flags & IORING_SETUP_NO_SQARRAY)) {
size_t sq_array_size;
- *sq_offset = off;
+ rl->sq_array_offset = off;
sq_array_size = array_size(sizeof(u32), sq_entries);
off = size_add(off, sq_array_size);
if (off == SIZE_MAX)
- return SIZE_MAX;
+ return -EOVERFLOW;
}
- return off;
+ rl->rings_size = off;
+ return 0;
}
static __cold void __io_req_caches_free(struct io_ring_ctx *ctx)
@@ -3346,28 +3356,20 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_uring_region_desc rd;
+ struct io_rings_layout __rl, *rl = &__rl;
struct io_rings *rings;
- size_t sq_array_offset;
- size_t sq_size, cq_size, sqe_size;
int ret;
/* make sure these are sane, as we already accounted them */
ctx->sq_entries = p->sq_entries;
ctx->cq_entries = p->cq_entries;
- sqe_size = sizeof(struct io_uring_sqe);
- if (p->flags & IORING_SETUP_SQE128)
- sqe_size *= 2;
- sq_size = array_size(sqe_size, p->sq_entries);
- if (sq_size == SIZE_MAX)
- return -EOVERFLOW;
- cq_size = rings_size(ctx->flags, p->sq_entries, p->cq_entries,
- &sq_array_offset);
- if (cq_size == SIZE_MAX)
- return -EOVERFLOW;
+ ret = rings_size(ctx->flags, p->sq_entries, p->cq_entries, rl);
+ if (ret)
+ return ret;
memset(&rd, 0, sizeof(rd));
- rd.size = PAGE_ALIGN(cq_size);
+ rd.size = PAGE_ALIGN(rl->rings_size);
if (ctx->flags & IORING_SETUP_NO_MMAP) {
rd.user_addr = p->cq_off.user_addr;
rd.flags |= IORING_MEM_REGION_TYPE_USER;
@@ -3378,10 +3380,10 @@ static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
ctx->rings = rings = io_region_get_ptr(&ctx->ring_region);
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
- ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
+ ctx->sq_array = (u32 *)((char *)rings + rl->sq_array_offset);
memset(&rd, 0, sizeof(rd));
- rd.size = PAGE_ALIGN(sq_size);
+ rd.size = PAGE_ALIGN(rl->sq_size);
if (ctx->flags & IORING_SETUP_NO_MMAP) {
rd.user_addr = p->sq_off.user_addr;
rd.flags |= IORING_MEM_REGION_TYPE_USER;
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index d8bc44acb9fa..5e544c2d27c8 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -17,6 +17,14 @@
#include <trace/events/io_uring.h>
#endif
+struct io_rings_layout {
+ /* size of CQ + headers + SQ offset array */
+ size_t rings_size;
+ size_t sq_size;
+
+ size_t sq_array_offset;
+};
+
struct io_ctx_config {
struct io_uring_params p;
struct io_uring_params __user *uptr;
@@ -139,8 +147,8 @@ static inline bool io_should_wake(struct io_wait_queue *iowq)
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
-unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
- unsigned int cq_entries, size_t *sq_offset);
+int rings_size(unsigned int flags, unsigned int sq_entries,
+ unsigned int cq_entries, struct io_rings_layout *rl);
int io_prepare_config(struct io_ctx_config *config);
bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow, bool cqe32);
diff --git a/io_uring/register.c b/io_uring/register.c
index 13385ac0f85a..98693021edbe 100644
--- a/io_uring/register.c
+++ b/io_uring/register.c
@@ -401,9 +401,9 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg)
struct io_ctx_config config;
struct io_uring_region_desc rd;
struct io_ring_ctx_rings o = { }, n = { }, *to_free = NULL;
- size_t size, sq_array_offset;
unsigned i, tail, old_head;
struct io_uring_params *p = &config.p;
+ struct io_rings_layout __rl, *rl = &__rl;
int ret;
memset(&config, 0, sizeof(config));
@@ -423,13 +423,12 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg)
if (unlikely(ret))
return ret;
- size = rings_size(p->flags, p->sq_entries, p->cq_entries,
- &sq_array_offset);
- if (size == SIZE_MAX)
- return -EOVERFLOW;
+ ret = rings_size(p->flags, p->sq_entries, p->cq_entries, rl);
+ if (ret)
+ return ret;
memset(&rd, 0, sizeof(rd));
- rd.size = PAGE_ALIGN(size);
+ rd.size = PAGE_ALIGN(rl->rings_size);
if (p->flags & IORING_SETUP_NO_MMAP) {
rd.user_addr = p->cq_off.user_addr;
rd.flags |= IORING_MEM_REGION_TYPE_USER;
@@ -458,17 +457,8 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg)
return -EFAULT;
}
- if (p->flags & IORING_SETUP_SQE128)
- size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
- else
- size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
- if (size == SIZE_MAX) {
- io_register_free_rings(ctx, &n);
- return -EOVERFLOW;
- }
-
memset(&rd, 0, sizeof(rd));
- rd.size = PAGE_ALIGN(size);
+ rd.size = PAGE_ALIGN(rl->sq_size);
if (p->flags & IORING_SETUP_NO_MMAP) {
rd.user_addr = p->sq_off.user_addr;
rd.flags |= IORING_MEM_REGION_TYPE_USER;
@@ -551,7 +541,7 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg)
/* all done, store old pointers and assign new ones */
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
- ctx->sq_array = (u32 *)((char *)n.rings + sq_array_offset);
+ ctx->sq_array = (u32 *)((char *)n.rings + rl->sq_array_offset);
ctx->sq_entries = p->sq_entries;
ctx->cq_entries = p->cq_entries;
--
2.49.0
next prev parent reply other threads:[~2025-11-12 12:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-12 12:45 [PATCH 0/7] further ring init cleanups Pavel Begunkov
2025-11-12 12:45 ` [PATCH 1/7] io_uring: refactor rings_size nosqarray handling Pavel Begunkov
2025-11-12 12:45 ` [PATCH 2/7] io_uring: use size_add helpers for ring offsets Pavel Begunkov
2025-11-12 12:45 ` [PATCH 3/7] io_uring: convert params to pointer in ring reisze Pavel Begunkov
2025-11-12 12:45 ` [PATCH 4/7] io_uring: introduce struct io_ctx_config Pavel Begunkov
2025-11-12 12:45 ` Pavel Begunkov [this message]
2025-11-12 12:45 ` [PATCH 6/7] io_uring: pre-calculate scq layout Pavel Begunkov
2025-11-12 12:45 ` [PATCH 7/7] io_uring: move cq/sq user offset init around Pavel Begunkov
2025-11-12 19:33 ` [PATCH 0/7] further ring init cleanups Jens Axboe
2025-11-13 14:28 ` Jens Axboe
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