[PATCH 0/4] io_uring: support vectored fixed kernel buffer

[PATCH 0/4] io_uring: support vectored fixed kernel buffer

[Ming Lei]

Hello Jens,

This patchset supports vectored fixed buffer for kernel bvec buffer,
and use it on for ublk/stripe.

Please review.

Thanks,
Ming


Ming Lei (4):
  io_uring: add validate_fixed_range() for validate fixed buffer
  block: add for_each_mp_bvec()
  io_uring: support vectored kernel fixed buffer
  selftests: ublk: enable zero copy for stripe target

 include/linux/bvec.h                  |   6 ++
 io_uring/rsrc.c                       | 125 +++++++++++++++++++++++---
 tools/testing/selftests/ublk/Makefile |   1 +
 tools/testing/selftests/ublk/stripe.c |  69 ++++++++++----
 4 files changed, 170 insertions(+), 31 deletions(-)

-- 
2.47.0

[PATCH 1/4] io_uring: add validate_fixed_range() for validate fixed buffer

[Ming Lei]

Add helper of validate_fixed_range() for validating fixed buffer
range.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 io_uring/rsrc.c | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 3f195e24777e..52e7492e863e 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1002,20 +1002,32 @@ int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
 }
 EXPORT_SYMBOL_GPL(io_buffer_unregister_bvec);
 
-static int io_import_fixed(int ddir, struct iov_iter *iter,
-			   struct io_mapped_ubuf *imu,
-			   u64 buf_addr, size_t len)
+static int validate_fixed_range(u64 buf_addr, size_t len,
+		const struct io_mapped_ubuf *imu)
 {
 	u64 buf_end;
-	size_t offset;
 
-	if (WARN_ON_ONCE(!imu))
-		return -EFAULT;
 	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
 		return -EFAULT;
 	/* not inside the mapped region */
 	if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
 		return -EFAULT;
+
+	return 0;
+}
+
+static int io_import_fixed(int ddir, struct iov_iter *iter,
+			   struct io_mapped_ubuf *imu,
+			   u64 buf_addr, size_t len)
+{
+	size_t offset;
+	int ret;
+
+	if (WARN_ON_ONCE(!imu))
+		return -EFAULT;
+	ret = validate_fixed_range(buf_addr, len, imu);
+	if (ret)
+		return ret;
 	if (!(imu->dir & (1 << ddir)))
 		return -EFAULT;
 
@@ -1305,12 +1317,12 @@ static int io_vec_fill_bvec(int ddir, struct iov_iter *iter,
 		u64 buf_addr = (u64)(uintptr_t)iovec[iov_idx].iov_base;
 		struct bio_vec *src_bvec;
 		size_t offset;
-		u64 buf_end;
+		int ret;
+
+		ret = validate_fixed_range(buf_addr, iov_len, imu);
+		if (unlikely(ret))
+			return ret;
 
-		if (unlikely(check_add_overflow(buf_addr, (u64)iov_len, &buf_end)))
-			return -EFAULT;
-		if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
-			return -EFAULT;
 		if (unlikely(!iov_len))
 			return -EFAULT;
 		if (unlikely(check_add_overflow(total_len, iov_len, &total_len)))
-- 
2.47.0

[PATCH 2/4] block: add for_each_mp_bvec()

[Ming Lei]

Add helper of for_each_mp_bvec() for io_uring to import fixed kernel
buffer.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 include/linux/bvec.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index ba8f52d48b94..204b22a99c4b 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -184,6 +184,12 @@ static inline void bvec_iter_advance_single(const struct bio_vec *bv,
 		((bvl = bvec_iter_bvec((bio_vec), (iter))), 1);	\
 	     bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len))
 
+#define for_each_mp_bvec(bvl, bio_vec, iter, start)			\
+	for (iter = (start);						\
+	     (iter).bi_size &&						\
+		((bvl = mp_bvec_iter_bvec((bio_vec), (iter))), 1);	\
+	     bvec_iter_advance_single((bio_vec), &(iter), (bvl).bv_len))
+
 /* for iterating one bio from start to end */
 #define BVEC_ITER_ALL_INIT (struct bvec_iter)				\
 {									\
-- 
2.47.0

[PATCH 3/4] io_uring: support vectored kernel fixed buffer

[Ming Lei]

io_uring has supported fixed kernel buffer via io_buffer_register_bvec()
and io_buffer_unregister_bvec().

The vectored fixed buffer has been ready, so it is natural to support
fixed kernel buffer, one use case is ublk.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 io_uring/rsrc.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 88 insertions(+), 3 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 52e7492e863e..82a7c2fcf58f 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1361,6 +1361,82 @@ static int io_estimate_bvec_size(struct iovec *iov, unsigned nr_iovs,
 	return max_segs;
 }
 
+static int io_vec_fill_kern_bvec(int ddir, struct iov_iter *iter,
+				 struct io_mapped_ubuf *imu,
+				 struct iovec *iovec, unsigned nr_iovs,
+				 struct iou_vec *vec)
+{
+	const struct bio_vec *src_bvec = imu->bvec;
+	struct bio_vec *res_bvec = vec->bvec;
+	unsigned res_idx = 0;
+	size_t total_len = 0;
+	unsigned iov_idx;
+
+	for (iov_idx = 0; iov_idx < nr_iovs; iov_idx++) {
+		size_t offset = (size_t)(uintptr_t)iovec[iov_idx].iov_base;
+		size_t iov_len = iovec[iov_idx].iov_len;
+		struct bvec_iter bi = {
+			.bi_size        = offset + iov_len,
+		};
+		struct bio_vec bv;
+
+		bvec_iter_advance(src_bvec, &bi, offset);
+		for_each_mp_bvec(bv, src_bvec, bi, bi)
+			res_bvec[res_idx++] = bv;
+		total_len += iov_len;
+	}
+	iov_iter_bvec(iter, ddir, res_bvec, res_idx, total_len);
+	return 0;
+}
+
+static int iov_kern_bvec_size(const struct iovec *iov,
+			      const struct io_mapped_ubuf *imu,
+			      unsigned int *nr_seg)
+{
+	size_t offset = (size_t)(uintptr_t)iov->iov_base;
+	const struct bio_vec *bvec = imu->bvec;
+	int start = 0, i = 0;
+	size_t off = 0;
+	int ret;
+
+	ret = validate_fixed_range(offset, iov->iov_len, imu);
+	if (unlikely(ret))
+		return ret;
+
+	for (i = 0; off < offset + iov->iov_len && i < imu->nr_bvecs;
+			off += bvec[i].bv_len, i++) {
+		if (offset >= off && offset < off + bvec[i].bv_len)
+			start = i;
+	}
+	*nr_seg = i - start;
+	return 0;
+}
+
+static int io_kern_bvec_size(struct iovec *iov, unsigned nr_iovs,
+			     struct io_mapped_ubuf *imu, unsigned *nr_segs)
+{
+	unsigned max_segs = 0;
+	size_t total_len = 0;
+	unsigned i;
+	int ret;
+
+	*nr_segs = 0;
+	for (i = 0; i < nr_iovs; i++) {
+		if (unlikely(!iov[i].iov_len))
+			return -EFAULT;
+		if (unlikely(check_add_overflow(total_len, iov[i].iov_len,
+						&total_len)))
+			return -EOVERFLOW;
+		ret = iov_kern_bvec_size(&iov[i], imu, &max_segs);
+		if (unlikely(ret))
+			return ret;
+		*nr_segs += max_segs;
+	}
+	if (total_len > MAX_RW_COUNT)
+		return -EINVAL;
+	return 0;
+}
+
 int io_import_reg_vec(int ddir, struct iov_iter *iter,
 			struct io_kiocb *req, struct iou_vec *vec,
 			unsigned nr_iovs, unsigned issue_flags)
@@ -1375,14 +1451,20 @@ int io_import_reg_vec(int ddir, struct iov_iter *iter,
 	if (!node)
 		return -EFAULT;
 	imu = node->buf;
-	if (imu->is_kbuf)
-		return -EOPNOTSUPP;
 	if (!(imu->dir & (1 << ddir)))
 		return -EFAULT;
 
 	iovec_off = vec->nr - nr_iovs;
 	iov = vec->iovec + iovec_off;
-	nr_segs = io_estimate_bvec_size(iov, nr_iovs, imu);
+
+	if (imu->is_kbuf) {
+		int ret = io_kern_bvec_size(iov, nr_iovs, imu, &nr_segs);
+
+		if (unlikely(ret))
+			return ret;
+	} else {
+		nr_segs = io_estimate_bvec_size(iov, nr_iovs, imu);
+	}
 
 	if (sizeof(struct bio_vec) > sizeof(struct iovec)) {
 		size_t bvec_bytes;
@@ -1409,6 +1491,9 @@ int io_import_reg_vec(int ddir, struct iov_iter *iter,
 		req->flags |= REQ_F_NEED_CLEANUP;
 	}
 
+	if (imu->is_kbuf)
+		return io_vec_fill_kern_bvec(ddir, iter, imu, iov, nr_iovs, vec);
+
 	return io_vec_fill_bvec(ddir, iter, imu, iov, nr_iovs, vec);
 }
 
-- 
2.47.0

[PATCH 4/4] selftests: ublk: enable zero copy for stripe target

[Ming Lei]

Use io_uring vectored fixed kernel buffer for handling stripe IO.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 tools/testing/selftests/ublk/Makefile |  1 +
 tools/testing/selftests/ublk/stripe.c | 69 ++++++++++++++++++++-------
 2 files changed, 53 insertions(+), 17 deletions(-)

diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
index d98680d64a2f..c7781efea0f3 100644
--- a/tools/testing/selftests/ublk/Makefile
+++ b/tools/testing/selftests/ublk/Makefile
@@ -17,6 +17,7 @@ TEST_PROGS += test_loop_05.sh
 TEST_PROGS += test_stripe_01.sh
 TEST_PROGS += test_stripe_02.sh
 TEST_PROGS += test_stripe_03.sh
+TEST_PROGS += test_stripe_04.sh
 
 TEST_PROGS += test_stress_01.sh
 TEST_PROGS += test_stress_02.sh
diff --git a/tools/testing/selftests/ublk/stripe.c b/tools/testing/selftests/ublk/stripe.c
index 98c564b12f3c..179731c3dd6f 100644
--- a/tools/testing/selftests/ublk/stripe.c
+++ b/tools/testing/selftests/ublk/stripe.c
@@ -111,43 +111,67 @@ static void calculate_stripe_array(const struct stripe_conf *conf,
 	}
 }
 
-static inline enum io_uring_op stripe_to_uring_op(const struct ublksrv_io_desc *iod)
+static inline enum io_uring_op stripe_to_uring_op(
+		const struct ublksrv_io_desc *iod, int zc)
 {
 	unsigned ublk_op = ublksrv_get_op(iod);
 
 	if (ublk_op == UBLK_IO_OP_READ)
-		return IORING_OP_READV;
+		return zc ? IORING_OP_READV_FIXED : IORING_OP_READV;
 	else if (ublk_op == UBLK_IO_OP_WRITE)
-		return IORING_OP_WRITEV;
+		return zc ? IORING_OP_WRITEV_FIXED : IORING_OP_WRITEV;
 	assert(0);
 }
 
 static int stripe_queue_tgt_rw_io(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
 {
 	const struct stripe_conf *conf = get_chunk_shift(q);
-	enum io_uring_op op = stripe_to_uring_op(iod);
+	int zc = !!(ublk_queue_use_zc(q) != 0);
+	enum io_uring_op op = stripe_to_uring_op(iod, zc);
 	struct io_uring_sqe *sqe[NR_STRIPE];
 	struct stripe_array *s = alloc_stripe_array(conf, iod);
 	struct ublk_io *io = ublk_get_io(q, tag);
-	int i;
+	int i, extra = zc ? 2 : 0;
 
 	io->private_data = s;
 	calculate_stripe_array(conf, iod, s);
 
-	ublk_queue_alloc_sqes(q, sqe, s->nr);
-	for (i = 0; i < s->nr; i++) {
-		struct stripe *t = &s->s[i];
+	ublk_queue_alloc_sqes(q, sqe, s->nr + extra);
+
+	if (zc) {
+		io_uring_prep_buf_register(sqe[0], 0, tag, q->q_id, tag);
+		sqe[0]->flags |= IOSQE_CQE_SKIP_SUCCESS | IOSQE_IO_HARDLINK;
+		sqe[0]->user_data = build_user_data(tag,
+			ublk_cmd_op_nr(sqe[0]->cmd_op), 0, 1);
+	}
+
+	for (i = zc; i < s->nr + extra - zc; i++) {
+		struct stripe *t = &s->s[i - zc];
 
 		io_uring_prep_rw(op, sqe[i],
 				t->seq + 1,
 				(void *)t->vec,
 				t->nr_vec,
 				t->start << 9);
-		io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
+		if (zc) {
+			sqe[i]->buf_index = tag;
+			io_uring_sqe_set_flags(sqe[i],
+					IOSQE_FIXED_FILE | IOSQE_IO_HARDLINK);
+		} else {
+			io_uring_sqe_set_flags(sqe[i], IOSQE_FIXED_FILE);
+		}
 		/* bit63 marks us as tgt io */
-		sqe[i]->user_data = build_user_data(tag, ublksrv_get_op(iod), i, 1);
+		sqe[i]->user_data = build_user_data(tag, ublksrv_get_op(iod), i - zc, 1);
+	}
+	if (zc) {
+		struct io_uring_sqe *unreg = sqe[s->nr + 1];
+
+		io_uring_prep_buf_unregister(unreg, 0, tag, q->q_id, tag);
+		unreg->user_data = build_user_data(tag, ublk_cmd_op_nr(unreg->cmd_op), 0, 1);
 	}
-	return s->nr;
+
+	/* register buffer is skip_success */
+	return s->nr + zc;
 }
 
 static int handle_flush(struct ublk_queue *q, const struct ublksrv_io_desc *iod, int tag)
@@ -208,19 +232,27 @@ static void ublk_stripe_io_done(struct ublk_queue *q, int tag,
 	struct ublk_io *io = ublk_get_io(q, tag);
 	int res = cqe->res;
 
-	if (res < 0) {
+	if (res < 0 || op != ublk_cmd_op_nr(UBLK_U_IO_UNREGISTER_IO_BUF)) {
 		if (!io->result)
 			io->result = res;
-		ublk_err("%s: io failure %d tag %u\n", __func__, res, tag);
+		if (res < 0)
+			ublk_err("%s: io failure %d tag %u\n", __func__, res, tag);
 	}
 
+	/* buffer register op is IOSQE_CQE_SKIP_SUCCESS */
+	if (op == ublk_cmd_op_nr(UBLK_U_IO_REGISTER_IO_BUF))
+		io->tgt_ios += 1;
+
 	/* fail short READ/WRITE simply */
 	if (op == UBLK_IO_OP_READ || op == UBLK_IO_OP_WRITE) {
 		unsigned seq = user_data_to_tgt_data(cqe->user_data);
 		struct stripe_array *s = io->private_data;
 
-		if (res < s->s[seq].vec->iov_len)
+		if (res < s->s[seq].nr_sects << 9) {
 			io->result = -EIO;
+			ublk_err("%s: short rw op %u res %d exp %u tag %u\n",
+					__func__, op, res, s->s[seq].vec->iov_len, tag);
+		}
 	}
 
 	if (ublk_completed_tgt_io(q, tag)) {
@@ -253,7 +285,7 @@ static int ublk_stripe_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
 	struct stripe_conf *conf;
 	unsigned chunk_shift;
 	loff_t bytes = 0;
-	int ret, i;
+	int ret, i, mul = 1;
 
 	if ((chunk_size & (chunk_size - 1)) || !chunk_size) {
 		ublk_err("invalid chunk size %u\n", chunk_size);
@@ -295,8 +327,11 @@ static int ublk_stripe_tgt_init(const struct dev_ctx *ctx, struct ublk_dev *dev)
 	dev->tgt.dev_size = bytes;
 	p.basic.dev_sectors = bytes >> 9;
 	dev->tgt.params = p;
-	dev->tgt.sq_depth = dev->dev_info.queue_depth * conf->nr_files;
-	dev->tgt.cq_depth = dev->dev_info.queue_depth * conf->nr_files;
+
+	if (dev->dev_info.flags & UBLK_F_SUPPORT_ZERO_COPY)
+		mul = 2;
+	dev->tgt.sq_depth = mul * dev->dev_info.queue_depth * conf->nr_files;
+	dev->tgt.cq_depth = mul * dev->dev_info.queue_depth * conf->nr_files;
 
 	printf("%s: shift %u files %u\n", __func__, conf->shift, conf->nr_files);
 
-- 
2.47.0

Re: [PATCH 1/4] io_uring: add validate_fixed_range() for validate fixed buffer

[Caleb Sander Mateos]

On Tue, Mar 25, 2025 at 6:52 AM Ming Lei <ming.lei@redhat.com> wrote:
>
> Add helper of validate_fixed_range() for validating fixed buffer
> range.
>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  io_uring/rsrc.c | 34 +++++++++++++++++++++++-----------
>  1 file changed, 23 insertions(+), 11 deletions(-)
>
> diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
> index 3f195e24777e..52e7492e863e 100644
> --- a/io_uring/rsrc.c
> +++ b/io_uring/rsrc.c
> @@ -1002,20 +1002,32 @@ int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
>  }
>  EXPORT_SYMBOL_GPL(io_buffer_unregister_bvec);
>
> -static int io_import_fixed(int ddir, struct iov_iter *iter,
> -                          struct io_mapped_ubuf *imu,
> -                          u64 buf_addr, size_t len)
> +static int validate_fixed_range(u64 buf_addr, size_t len,
> +               const struct io_mapped_ubuf *imu)
>  {
>         u64 buf_end;
> -       size_t offset;
>
> -       if (WARN_ON_ONCE(!imu))
> -               return -EFAULT;
>         if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))
>                 return -EFAULT;
>         /* not inside the mapped region */
>         if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
>                 return -EFAULT;
> +
> +       return 0;

It's nice to avoid this code duplication. It looks like
validate_fixed_range() could return a bool instead and leave the
return code up to the caller, but I don't feel strongly either way.

Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>

> +}
> +
> +static int io_import_fixed(int ddir, struct iov_iter *iter,
> +                          struct io_mapped_ubuf *imu,
> +                          u64 buf_addr, size_t len)
> +{
> +       size_t offset;
> +       int ret;
> +
> +       if (WARN_ON_ONCE(!imu))
> +               return -EFAULT;
> +       ret = validate_fixed_range(buf_addr, len, imu);
> +       if (ret)
> +               return ret;
>         if (!(imu->dir & (1 << ddir)))
>                 return -EFAULT;
>
> @@ -1305,12 +1317,12 @@ static int io_vec_fill_bvec(int ddir, struct iov_iter *iter,
>                 u64 buf_addr = (u64)(uintptr_t)iovec[iov_idx].iov_base;
>                 struct bio_vec *src_bvec;
>                 size_t offset;
> -               u64 buf_end;
> +               int ret;
> +
> +               ret = validate_fixed_range(buf_addr, iov_len, imu);
> +               if (unlikely(ret))
> +                       return ret;
>
> -               if (unlikely(check_add_overflow(buf_addr, (u64)iov_len, &buf_end)))
> -                       return -EFAULT;
> -               if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))
> -                       return -EFAULT;
>                 if (unlikely(!iov_len))
>                         return -EFAULT;
>                 if (unlikely(check_add_overflow(total_len, iov_len, &total_len)))
> --
> 2.47.0
>

Re: [PATCH 0/4] io_uring: support vectored fixed kernel buffer

[Ming Lei]

On Tue, Mar 25, 2025 at 09:51:49PM +0800, Ming Lei wrote:
> Hello Jens,
> 
> This patchset supports vectored fixed buffer for kernel bvec buffer,
> and use it on for ublk/stripe.
> 
> Please review.
> 
> Thanks,
> Ming
> 
> 
> Ming Lei (4):
>   io_uring: add validate_fixed_range() for validate fixed buffer
>   block: add for_each_mp_bvec()
>   io_uring: support vectored kernel fixed buffer
>   selftests: ublk: enable zero copy for stripe target

Hello,

Ping...


Thanks,
Ming

Re: [PATCH 0/4] io_uring: support vectored fixed kernel buffer

[Jens Axboe]

On 4/2/25 1:57 AM, Ming Lei wrote:
> On Tue, Mar 25, 2025 at 09:51:49PM +0800, Ming Lei wrote:
>> Hello Jens,
>>
>> This patchset supports vectored fixed buffer for kernel bvec buffer,
>> and use it on for ublk/stripe.
>>
>> Please review.
>>
>> Thanks,
>> Ming
>>
>>
>> Ming Lei (4):
>>   io_uring: add validate_fixed_range() for validate fixed buffer
>>   block: add for_each_mp_bvec()
>>   io_uring: support vectored kernel fixed buffer
>>   selftests: ublk: enable zero copy for stripe target
> 
> Hello,
> 
> Ping...

Looks fine to me and pretty straight forward, but it was in the merge
window. Anything that makes this important for 6.15? We can still
include it if so. If not, let's take a look for 6.16 when the merge
window closes.

-- 
Jens Axboe

Re: [PATCH 0/4] io_uring: support vectored fixed kernel buffer

[Pavel Begunkov]

On 4/2/25 12:59, Jens Axboe wrote:
> On 4/2/25 1:57 AM, Ming Lei wrote:
>> On Tue, Mar 25, 2025 at 09:51:49PM +0800, Ming Lei wrote:
>>> Hello Jens,
>>>
>>> This patchset supports vectored fixed buffer for kernel bvec buffer,
>>> and use it on for ublk/stripe.
>>>
>>> Please review.
>>>
>>> Thanks,
>>> Ming
>>>
>>>
>>> Ming Lei (4):
>>>    io_uring: add validate_fixed_range() for validate fixed buffer
>>>    block: add for_each_mp_bvec()
>>>    io_uring: support vectored kernel fixed buffer
>>>    selftests: ublk: enable zero copy for stripe target
>>
>> Hello,
>>
>> Ping...
> 
> Looks fine to me and pretty straight forward, but it was in the merge
> window. Anything that makes this important for 6.15? We can still
> include it if so. If not, let's take a look for 6.16 when the merge
> window closes.

fwiw, I looked through it, looks correct, but it'd be a good
to test it aside from ublk. I guess I'll just extend a kernel
hack I used before.

No opinion on 6.15 vs 6.16, but the argument might be to have
it in the same release with ublk zc, and have less probing
for the user.

-- 
Pavel Begunkov

Re: [PATCH 0/4] io_uring: support vectored fixed kernel buffer

[Jens Axboe]

On 4/2/25 6:13 AM, Pavel Begunkov wrote:
> On 4/2/25 12:59, Jens Axboe wrote:
>> On 4/2/25 1:57 AM, Ming Lei wrote:
>>> On Tue, Mar 25, 2025 at 09:51:49PM +0800, Ming Lei wrote:
>>>> Hello Jens,
>>>>
>>>> This patchset supports vectored fixed buffer for kernel bvec buffer,
>>>> and use it on for ublk/stripe.
>>>>
>>>> Please review.
>>>>
>>>> Thanks,
>>>> Ming
>>>>
>>>>
>>>> Ming Lei (4):
>>>>    io_uring: add validate_fixed_range() for validate fixed buffer
>>>>    block: add for_each_mp_bvec()
>>>>    io_uring: support vectored kernel fixed buffer
>>>>    selftests: ublk: enable zero copy for stripe target
>>>
>>> Hello,
>>>
>>> Ping...
>>
>> Looks fine to me and pretty straight forward, but it was in the merge
>> window. Anything that makes this important for 6.15? We can still
>> include it if so. If not, let's take a look for 6.16 when the merge
>> window closes.
> 
> fwiw, I looked through it, looks correct, but it'd be a good
> to test it aside from ublk. I guess I'll just extend a kernel
> hack I used before.
> 
> No opinion on 6.15 vs 6.16, but the argument might be to have
> it in the same release with ublk zc, and have less probing
> for the user.

That's a good argument for 6.15 actually, rather than split the vectored
feature over two releases... I'll queue it up.

-- 
Jens Axboe

Re: [PATCH 0/4] io_uring: support vectored fixed kernel buffer

[Jens Axboe]

On Tue, 25 Mar 2025 21:51:49 +0800, Ming Lei wrote:
> This patchset supports vectored fixed buffer for kernel bvec buffer,
> and use it on for ublk/stripe.
> 
> Please review.
> 
> Thanks,
> Ming
> 
> [...]

Applied, thanks!

[1/4] io_uring: add validate_fixed_range() for validate fixed buffer
      (no commit info)
[2/4] block: add for_each_mp_bvec()
      (no commit info)
[3/4] io_uring: support vectored kernel fixed buffer
      (no commit info)
[4/4] selftests: ublk: enable zero copy for stripe target
      (no commit info)

Best regards,
-- 
Jens Axboe

Re: [PATCH 4/4] selftests: ublk: enable zero copy for stripe target

[Uday Shankar]

On Tue, Mar 25, 2025 at 09:51:53PM +0800, Ming Lei wrote:
> Use io_uring vectored fixed kernel buffer for handling stripe IO.
> 
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  tools/testing/selftests/ublk/Makefile |  1 +
>  tools/testing/selftests/ublk/stripe.c | 69 ++++++++++++++++++++-------
>  2 files changed, 53 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
> index d98680d64a2f..c7781efea0f3 100644
> --- a/tools/testing/selftests/ublk/Makefile
> +++ b/tools/testing/selftests/ublk/Makefile
> @@ -17,6 +17,7 @@ TEST_PROGS += test_loop_05.sh
>  TEST_PROGS += test_stripe_01.sh
>  TEST_PROGS += test_stripe_02.sh
>  TEST_PROGS += test_stripe_03.sh
> +TEST_PROGS += test_stripe_04.sh

This patch is missing the new file test_stripe_04.sh, causing ublk
selftests to be broken on block/for-next. Can you fix?

Re: [PATCH 4/4] selftests: ublk: enable zero copy for stripe target

[Ming Lei]

On Thu, Apr 03, 2025 at 04:42:40PM -0600, Uday Shankar wrote:
> On Tue, Mar 25, 2025 at 09:51:53PM +0800, Ming Lei wrote:
> > Use io_uring vectored fixed kernel buffer for handling stripe IO.
> > 
> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
> > ---
> >  tools/testing/selftests/ublk/Makefile |  1 +
> >  tools/testing/selftests/ublk/stripe.c | 69 ++++++++++++++++++++-------
> >  2 files changed, 53 insertions(+), 17 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
> > index d98680d64a2f..c7781efea0f3 100644
> > --- a/tools/testing/selftests/ublk/Makefile
> > +++ b/tools/testing/selftests/ublk/Makefile
> > @@ -17,6 +17,7 @@ TEST_PROGS += test_loop_05.sh
> >  TEST_PROGS += test_stripe_01.sh
> >  TEST_PROGS += test_stripe_02.sh
> >  TEST_PROGS += test_stripe_03.sh
> > +TEST_PROGS += test_stripe_04.sh
> 
> This patch is missing the new file test_stripe_04.sh, causing ublk
> selftests to be broken on block/for-next. Can you fix?

The fix is posted out:

https://lore.kernel.org/linux-block/20250404001849.1443064-1-ming.lei@redhat.com/

Thanks for the report and sorry for the trouble.



Thanks,
Ming