* [RFC PATCH] RDMA/siw: use kzalloc_flex
@ 2026-04-21 19:28 bernard.metzler
2026-04-21 21:32 ` Rosen Penev
2026-04-28 15:55 ` Jason Gunthorpe
0 siblings, 2 replies; 4+ messages in thread
From: bernard.metzler @ 2026-04-21 19:28 UTC (permalink / raw)
To: rosenp; +Cc: jgg, leon, kees, gustavoars, linux-rdma, Bernard Metzler
From: Bernard Metzler <bernard.metzler@linux.dev>
Simplify umem allocation by using flexible array member.
Add __counted_by to get extra runtime analysis.
Suggested-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Bernard Metzler <bernard.metzler@linux.dev>
---
drivers/infiniband/sw/siw/siw.h | 4 ++--
drivers/infiniband/sw/siw/siw_mem.c | 19 ++++++-------------
drivers/infiniband/sw/siw/siw_mem.h | 2 +-
3 files changed, 9 insertions(+), 16 deletions(-)
diff --git a/drivers/infiniband/sw/siw/siw.h b/drivers/infiniband/sw/siw/siw.h
index f5fd71717b80..a4088caec2ae 100644
--- a/drivers/infiniband/sw/siw/siw.h
+++ b/drivers/infiniband/sw/siw/siw.h
@@ -119,9 +119,9 @@ struct siw_page_chunk {
struct siw_umem {
struct ib_umem *base_mem;
- struct siw_page_chunk *page_chunk;
- int num_pages;
+ int num_chunks;
u64 fp_addr; /* First page base address */
+ struct siw_page_chunk page_chunk[] __counted_by(num_chunks);
};
struct siw_pble {
diff --git a/drivers/infiniband/sw/siw/siw_mem.c b/drivers/infiniband/sw/siw/siw_mem.c
index 98c802b3ed72..56d24db729d0 100644
--- a/drivers/infiniband/sw/siw/siw_mem.c
+++ b/drivers/infiniband/sw/siw/siw_mem.c
@@ -41,16 +41,14 @@ struct siw_mem *siw_mem_id2obj(struct siw_device *sdev, int stag_index)
void siw_umem_release(struct siw_umem *umem)
{
- int i, num_pages = umem->num_pages;
+ int i, num_chunks = umem->num_chunks;
if (umem->base_mem)
ib_umem_release(umem->base_mem);
- for (i = 0; num_pages > 0; i++) {
+ for (i = 0; i < num_chunks; i++)
kfree(umem->page_chunk[i].plist);
- num_pages -= PAGES_PER_CHUNK;
- }
- kfree(umem->page_chunk);
+
kfree(umem);
}
@@ -347,16 +345,12 @@ struct siw_umem *siw_umem_get(struct ib_device *base_dev, u64 start,
num_pages = PAGE_ALIGN(start + len - first_page_va) >> PAGE_SHIFT;
num_chunks = (num_pages >> CHUNK_SHIFT) + 1;
- umem = kzalloc_obj(*umem);
+ umem = kzalloc_flex(*umem, page_chunk, num_chunks);
if (!umem)
return ERR_PTR(-ENOMEM);
- umem->page_chunk =
- kzalloc_objs(struct siw_page_chunk, num_chunks);
- if (!umem->page_chunk) {
- rv = -ENOMEM;
- goto err_out;
- }
+ umem->num_chunks = num_chunks;
+
base_mem = ib_umem_get(base_dev, start, len, rights);
if (IS_ERR(base_mem)) {
rv = PTR_ERR(base_mem);
@@ -385,7 +379,6 @@ struct siw_umem *siw_umem_get(struct ib_device *base_dev, u64 start,
umem->page_chunk[i].plist = plist;
while (nents--) {
*plist = sg_page_iter_page(&sg_iter);
- umem->num_pages++;
num_pages--;
plist++;
if (!__sg_page_iter_next(&sg_iter))
diff --git a/drivers/infiniband/sw/siw/siw_mem.h b/drivers/infiniband/sw/siw/siw_mem.h
index 8e769d30e2ac..86af61d422d5 100644
--- a/drivers/infiniband/sw/siw/siw_mem.h
+++ b/drivers/infiniband/sw/siw/siw_mem.h
@@ -61,7 +61,7 @@ static inline struct page *siw_get_upage(struct siw_umem *umem, u64 addr)
chunk_idx = page_idx >> CHUNK_SHIFT,
page_in_chunk = page_idx & ~CHUNK_MASK;
- if (likely(page_idx < umem->num_pages))
+ if (likely(chunk_idx < umem->num_chunks))
return umem->page_chunk[chunk_idx].plist[page_in_chunk];
return NULL;
--
2.50.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [RFC PATCH] RDMA/siw: use kzalloc_flex
2026-04-21 19:28 [RFC PATCH] RDMA/siw: use kzalloc_flex bernard.metzler
@ 2026-04-21 21:32 ` Rosen Penev
2026-04-28 15:55 ` Jason Gunthorpe
1 sibling, 0 replies; 4+ messages in thread
From: Rosen Penev @ 2026-04-21 21:32 UTC (permalink / raw)
To: bernard.metzler; +Cc: jgg, leon, kees, gustavoars, linux-rdma
On Tue, Apr 21, 2026 at 12:28 PM <bernard.metzler@linux.dev> wrote:
>
> From: Bernard Metzler <bernard.metzler@linux.dev>
>
> Simplify umem allocation by using flexible array member.
> Add __counted_by to get extra runtime analysis.
>
> Suggested-by: Rosen Penev <rosenp@gmail.com>
> Signed-off-by: Bernard Metzler <bernard.metzler@linux.dev>
LGTM
> ---
> drivers/infiniband/sw/siw/siw.h | 4 ++--
> drivers/infiniband/sw/siw/siw_mem.c | 19 ++++++-------------
> drivers/infiniband/sw/siw/siw_mem.h | 2 +-
> 3 files changed, 9 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/infiniband/sw/siw/siw.h b/drivers/infiniband/sw/siw/siw.h
> index f5fd71717b80..a4088caec2ae 100644
> --- a/drivers/infiniband/sw/siw/siw.h
> +++ b/drivers/infiniband/sw/siw/siw.h
> @@ -119,9 +119,9 @@ struct siw_page_chunk {
>
> struct siw_umem {
> struct ib_umem *base_mem;
> - struct siw_page_chunk *page_chunk;
> - int num_pages;
> + int num_chunks;
> u64 fp_addr; /* First page base address */
> + struct siw_page_chunk page_chunk[] __counted_by(num_chunks);
> };
>
> struct siw_pble {
> diff --git a/drivers/infiniband/sw/siw/siw_mem.c b/drivers/infiniband/sw/siw/siw_mem.c
> index 98c802b3ed72..56d24db729d0 100644
> --- a/drivers/infiniband/sw/siw/siw_mem.c
> +++ b/drivers/infiniband/sw/siw/siw_mem.c
> @@ -41,16 +41,14 @@ struct siw_mem *siw_mem_id2obj(struct siw_device *sdev, int stag_index)
>
> void siw_umem_release(struct siw_umem *umem)
> {
> - int i, num_pages = umem->num_pages;
> + int i, num_chunks = umem->num_chunks;
>
> if (umem->base_mem)
> ib_umem_release(umem->base_mem);
>
> - for (i = 0; num_pages > 0; i++) {
> + for (i = 0; i < num_chunks; i++)
> kfree(umem->page_chunk[i].plist);
> - num_pages -= PAGES_PER_CHUNK;
> - }
> - kfree(umem->page_chunk);
> +
> kfree(umem);
> }
>
> @@ -347,16 +345,12 @@ struct siw_umem *siw_umem_get(struct ib_device *base_dev, u64 start,
> num_pages = PAGE_ALIGN(start + len - first_page_va) >> PAGE_SHIFT;
> num_chunks = (num_pages >> CHUNK_SHIFT) + 1;
>
> - umem = kzalloc_obj(*umem);
> + umem = kzalloc_flex(*umem, page_chunk, num_chunks);
> if (!umem)
> return ERR_PTR(-ENOMEM);
>
> - umem->page_chunk =
> - kzalloc_objs(struct siw_page_chunk, num_chunks);
> - if (!umem->page_chunk) {
> - rv = -ENOMEM;
> - goto err_out;
> - }
> + umem->num_chunks = num_chunks;
> +
> base_mem = ib_umem_get(base_dev, start, len, rights);
> if (IS_ERR(base_mem)) {
> rv = PTR_ERR(base_mem);
> @@ -385,7 +379,6 @@ struct siw_umem *siw_umem_get(struct ib_device *base_dev, u64 start,
> umem->page_chunk[i].plist = plist;
> while (nents--) {
> *plist = sg_page_iter_page(&sg_iter);
> - umem->num_pages++;
> num_pages--;
> plist++;
> if (!__sg_page_iter_next(&sg_iter))
> diff --git a/drivers/infiniband/sw/siw/siw_mem.h b/drivers/infiniband/sw/siw/siw_mem.h
> index 8e769d30e2ac..86af61d422d5 100644
> --- a/drivers/infiniband/sw/siw/siw_mem.h
> +++ b/drivers/infiniband/sw/siw/siw_mem.h
> @@ -61,7 +61,7 @@ static inline struct page *siw_get_upage(struct siw_umem *umem, u64 addr)
> chunk_idx = page_idx >> CHUNK_SHIFT,
> page_in_chunk = page_idx & ~CHUNK_MASK;
>
> - if (likely(page_idx < umem->num_pages))
> + if (likely(chunk_idx < umem->num_chunks))
> return umem->page_chunk[chunk_idx].plist[page_in_chunk];
>
> return NULL;
> --
> 2.50.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFC PATCH] RDMA/siw: use kzalloc_flex
2026-04-21 19:28 [RFC PATCH] RDMA/siw: use kzalloc_flex bernard.metzler
2026-04-21 21:32 ` Rosen Penev
@ 2026-04-28 15:55 ` Jason Gunthorpe
2026-04-29 16:04 ` Bernard Metzler
1 sibling, 1 reply; 4+ messages in thread
From: Jason Gunthorpe @ 2026-04-28 15:55 UTC (permalink / raw)
To: bernard.metzler; +Cc: rosenp, leon, kees, gustavoars, linux-rdma
On Tue, Apr 21, 2026 at 09:28:21PM +0200, bernard.metzler@linux.dev wrote:
> From: Bernard Metzler <bernard.metzler@linux.dev>
>
> Simplify umem allocation by using flexible array member.
> Add __counted_by to get extra runtime analysis.
>
> Suggested-by: Rosen Penev <rosenp@gmail.com>
> Signed-off-by: Bernard Metzler <bernard.metzler@linux.dev>
> ---
> drivers/infiniband/sw/siw/siw.h | 4 ++--
> drivers/infiniband/sw/siw/siw_mem.c | 19 ++++++-------------
> drivers/infiniband/sw/siw/siw_mem.h | 2 +-
> 3 files changed, 9 insertions(+), 16 deletions(-)
Sashiko has quite a few interesting things to say about this:
https://sashiko.dev/#/patchset/20260421192821.2305-1-bernard.metzler%40linux.dev
Jason
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFC PATCH] RDMA/siw: use kzalloc_flex
2026-04-28 15:55 ` Jason Gunthorpe
@ 2026-04-29 16:04 ` Bernard Metzler
0 siblings, 0 replies; 4+ messages in thread
From: Bernard Metzler @ 2026-04-29 16:04 UTC (permalink / raw)
To: Jason Gunthorpe; +Cc: rosenp, leon, kees, gustavoars, linux-rdma
On 28.04.2026 17:55, Jason Gunthorpe wrote:
> On Tue, Apr 21, 2026 at 09:28:21PM +0200, bernard.metzler@linux.dev wrote:
>> From: Bernard Metzler <bernard.metzler@linux.dev>
>>
>> Simplify umem allocation by using flexible array member.
>> Add __counted_by to get extra runtime analysis.
>>
>> Suggested-by: Rosen Penev <rosenp@gmail.com>
>> Signed-off-by: Bernard Metzler <bernard.metzler@linux.dev>
>> ---
>> drivers/infiniband/sw/siw/siw.h | 4 ++--
>> drivers/infiniband/sw/siw/siw_mem.c | 19 ++++++-------------
>> drivers/infiniband/sw/siw/siw_mem.h | 2 +-
>> 3 files changed, 9 insertions(+), 16 deletions(-)
>
> Sashiko has quite a few interesting things to say about this:
>
> https://sashiko.dev/#/patchset/20260421192821.2305-1-bernard.metzler%40linux.dev
>
> Jason
Excellent. I thought about that issue, but probably my
conclusion that's all right is just wrong.
I'll rework.
Thanks,
Bernard.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2026-04-21 19:28 [RFC PATCH] RDMA/siw: use kzalloc_flex bernard.metzler
2026-04-21 21:32 ` Rosen Penev
2026-04-28 15:55 ` Jason Gunthorpe
2026-04-29 16:04 ` Bernard Metzler
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