[PATCH 0/4] random setup cleanups

[PATCH 0/4] random setup cleanups

[Pavel Begunkov]

Simple cleanups extracted from another series. Nothing noteworthy
apart from that I needed Patch 1 in a couple of places already,
but it's still a good follow up to recent fixes.

Pavel Begunkov (4):
  io_uring: add helper calculating region byte size
  io_uring: pass sq entires in the params struct
  io_uring: use mem_is_zero to check ring params
  io_uring: move flags check to io_uring_sanitise_params

 io_uring/io_uring.c | 22 ++++++++++++----------
 io_uring/io_uring.h |  2 +-
 io_uring/memmap.c   |  4 ++--
 io_uring/memmap.h   |  5 +++++
 io_uring/register.c |  2 +-
 5 files changed, 21 insertions(+), 14 deletions(-)

-- 
2.49.0

[PATCH 1/4] io_uring: add helper calculating region byte size

[Pavel Begunkov]

There has been type related issues with region size calculation, add an
utility helper function that returns the size and handles type
conversions right.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/memmap.c | 4 ++--
 io_uring/memmap.h | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/io_uring/memmap.c b/io_uring/memmap.c
index 24da17a5f08f..dc4bfc5b6fb8 100644
--- a/io_uring/memmap.c
+++ b/io_uring/memmap.c
@@ -134,7 +134,7 @@ static int io_region_init_ptr(struct io_mapped_region *mr)
 static int io_region_pin_pages(struct io_mapped_region *mr,
 			       struct io_uring_region_desc *reg)
 {
-	unsigned long size = mr->nr_pages << PAGE_SHIFT;
+	size_t size = io_region_size(mr);
 	struct page **pages;
 	int nr_pages;
 
@@ -154,7 +154,7 @@ static int io_region_allocate_pages(struct io_mapped_region *mr,
 				    unsigned long mmap_offset)
 {
 	gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN;
-	size_t size = (size_t) mr->nr_pages << PAGE_SHIFT;
+	size_t size = io_region_size(mr);
 	unsigned long nr_allocated;
 	struct page **pages;
 
diff --git a/io_uring/memmap.h b/io_uring/memmap.h
index a6c63ca2c6f1..d2a940682d19 100644
--- a/io_uring/memmap.h
+++ b/io_uring/memmap.h
@@ -43,4 +43,9 @@ static inline void io_region_publish(struct io_ring_ctx *ctx,
 	*dst_region = *src_region;
 }
 
+static inline size_t io_region_size(struct io_mapped_region *mr)
+{
+	return (size_t)mr->nr_pages << PAGE_SHIFT;
+}
+
 #endif
-- 
2.49.0

[PATCH 2/4] io_uring: pass sq entires in the params struct

[Pavel Begunkov]

There is no need to pass the user requested number of SQ entries
separately from the main parameter structure io_uring_params. Initialise
it at the beginning and stop passing it in favour of struct
io_uring_params::sq_entries.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/io_uring.c | 11 +++++++----
 io_uring/io_uring.h |  2 +-
 io_uring/register.c |  2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index d11d0e9723a1..023b0e3a829c 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3479,8 +3479,10 @@ static int io_uring_sanitise_params(struct io_uring_params *p)
 	return 0;
 }
 
-int io_uring_fill_params(unsigned entries, struct io_uring_params *p)
+int io_uring_fill_params(struct io_uring_params *p)
 {
+	unsigned entries = p->sq_entries;
+
 	if (!entries)
 		return -EINVAL;
 	if (entries > IORING_MAX_ENTRIES) {
@@ -3542,7 +3544,7 @@ int io_uring_fill_params(unsigned entries, struct io_uring_params *p)
 	return 0;
 }
 
-static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
+static __cold int io_uring_create(struct io_uring_params *p,
 				  struct io_uring_params __user *params)
 {
 	struct io_ring_ctx *ctx;
@@ -3554,7 +3556,7 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
 	if (ret)
 		return ret;
 
-	ret = io_uring_fill_params(entries, p);
+	ret = io_uring_fill_params(p);
 	if (unlikely(ret))
 		return ret;
 
@@ -3693,7 +3695,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
 
 	if (p.flags & ~IORING_SETUP_FLAGS)
 		return -EINVAL;
-	return io_uring_create(entries, &p, params);
+	p.sq_entries = entries;
+	return io_uring_create(&p, params);
 }
 
 static inline int io_uring_allowed(void)
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 23c268ab1c8f..b2251446497a 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -136,7 +136,7 @@ static inline bool io_should_wake(struct io_wait_queue *iowq)
 
 unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
 			 unsigned int cq_entries, size_t *sq_offset);
-int io_uring_fill_params(unsigned entries, struct io_uring_params *p);
+int io_uring_fill_params(struct io_uring_params *p);
 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow, bool cqe32);
 int io_run_task_work_sig(struct io_ring_ctx *ctx);
 int io_run_local_work(struct io_ring_ctx *ctx, int min_events, int max_events);
diff --git a/io_uring/register.c b/io_uring/register.c
index 023f5e7a18da..afb924ceb9b6 100644
--- a/io_uring/register.c
+++ b/io_uring/register.c
@@ -416,7 +416,7 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg)
 	/* properties that are always inherited */
 	p.flags |= (ctx->flags & COPY_FLAGS);
 
-	ret = io_uring_fill_params(p.sq_entries, &p);
+	ret = io_uring_fill_params(&p);
 	if (unlikely(ret))
 		return ret;
 
-- 
2.49.0

[PATCH 3/4] io_uring: use mem_is_zero to check ring params

[Pavel Begunkov]

mem_is_zero() does the job without hand rolled loops, use that to verify
reserved fields of ring params.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/io_uring.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 023b0e3a829c..af7b4cbe9850 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3684,14 +3684,12 @@ static __cold int io_uring_create(struct io_uring_params *p,
 static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
 {
 	struct io_uring_params p;
-	int i;
 
 	if (copy_from_user(&p, params, sizeof(p)))
 		return -EFAULT;
-	for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
-		if (p.resv[i])
-			return -EINVAL;
-	}
+
+	if (!mem_is_zero(&p.resv, sizeof(p.resv)))
+		return -EINVAL;
 
 	if (p.flags & ~IORING_SETUP_FLAGS)
 		return -EINVAL;
-- 
2.49.0

[PATCH 4/4] io_uring: move flags check to io_uring_sanitise_params

[Pavel Begunkov]

io_uring_sanitise_params() sanitises most of the setup flags invariants,
move the IORING_SETUP_FLAGS check from io_uring_setup() into it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 io_uring/io_uring.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index af7b4cbe9850..7e069d56b8a1 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3430,6 +3430,9 @@ static int io_uring_sanitise_params(struct io_uring_params *p)
 {
 	unsigned flags = p->flags;
 
+	if (flags & ~IORING_SETUP_FLAGS)
+		return -EINVAL;
+
 	/* There is no way to mmap rings without a real fd */
 	if ((flags & IORING_SETUP_REGISTERED_FD_ONLY) &&
 	    !(flags & IORING_SETUP_NO_MMAP))
@@ -3691,8 +3694,6 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
 	if (!mem_is_zero(&p.resv, sizeof(p.resv)))
 		return -EINVAL;
 
-	if (p.flags & ~IORING_SETUP_FLAGS)
-		return -EINVAL;
 	p.sq_entries = entries;
 	return io_uring_create(&p, params);
 }
-- 
2.49.0

Re: [PATCH 0/4] random setup cleanups

[Jens Axboe]

On Mon, 10 Nov 2025 13:04:48 +0000, Pavel Begunkov wrote:
> Simple cleanups extracted from another series. Nothing noteworthy
> apart from that I needed Patch 1 in a couple of places already,
> but it's still a good follow up to recent fixes.
> 
> Pavel Begunkov (4):
>   io_uring: add helper calculating region byte size
>   io_uring: pass sq entires in the params struct
>   io_uring: use mem_is_zero to check ring params
>   io_uring: move flags check to io_uring_sanitise_params
> 
> [...]

Applied, thanks!

[1/4] io_uring: add helper calculating region byte size
      commit: c5b09a6d1dfab3ac97230cc91a32d19a8f692232
[2/4] io_uring: pass sq entires in the params struct
      (no commit info)
[3/4] io_uring: use mem_is_zero to check ring params
      commit: 44d5ba73f6147b36316c713094ef56a7d93e5076
[4/4] io_uring: move flags check to io_uring_sanitise_params
      commit: 4d7352becf5609047112f91883071a289c44e221

Best regards,
-- 
Jens Axboe