Hi Huan,
>
> When PAGE_SIZE 4096, MAX_PAGE_ORDER 10, 64bit machine,
> page_alloc only support 4MB.
> If above this, trigger this warn and return NULL.
>
> udmabuf can change size limit, if change it to 3072(3GB), and then alloc
> 3GB udmabuf, will fail create.
>
> [ 4080.876581] ------------[ cut here ]------------
> [ 4080.876843] WARNING: CPU: 3 PID: 2015 at mm/page_alloc.c:4556
> __alloc_pages+0x2c8/0x350
> [ 4080.878839] RIP: 0010:__alloc_pages+0x2c8/0x350
> [ 4080.879470] Call Trace:
> [ 4080.879473] <TASK>
> [ 4080.879473] ? __alloc_pages+0x2c8/0x350
> [ 4080.879475] ? __warn.cold+0x8e/0xe8
> [ 4080.880647] ? __alloc_pages+0x2c8/0x350
> [ 4080.880909] ? report_bug+0xff/0x140
> [ 4080.881175] ? handle_bug+0x3c/0x80
> [ 4080.881556] ? exc_invalid_op+0x17/0x70
> [ 4080.881559] ? asm_exc_invalid_op+0x1a/0x20
> [ 4080.882077] ? udmabuf_create+0x131/0x400
>
> Because MAX_PAGE_ORDER, kmalloc can max alloc 4096 * (1 << 10), 4MB
> memory, each array entry is pointer(8byte), so can save 524288 pages(2GB).
>
> Further more, costly order(order 3) may not be guaranteed that it can be
> applied for, due to fragmentation.
>
> This patch change udmabuf array use kvmalloc_array, this can fallback
> alloc into vmalloc, which can guarantee allocation for any size and does
> not affect the performance of kmalloc allocations.
>
> Signed-off-by: Huan Yang <link@xxxxxxxx>
> Acked-by: Christian König <christian.koenig@xxxxxxx>
> ---
> drivers/dma-buf/udmabuf.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
> index 475268d4ebb1..af2391cea0bf 100644
> --- a/drivers/dma-buf/udmabuf.c
> +++ b/drivers/dma-buf/udmabuf.c
> @@ -73,7 +73,7 @@ static int vmap_udmabuf(struct dma_buf *buf, struct
> iosys_map *map)
>
> dma_resv_assert_held(buf->resv);
>
> - pages = kmalloc_array(ubuf->pagecount, sizeof(*pages),
> GFP_KERNEL);
> + pages = kvmalloc_array(ubuf->pagecount, sizeof(*pages),
> GFP_KERNEL);
> if (!pages)
> return -ENOMEM;
>
> @@ -81,7 +81,7 @@ static int vmap_udmabuf(struct dma_buf *buf, struct
> iosys_map *map)
> pages[pg] = &ubuf->folios[pg]->page;
>
> vaddr = vm_map_ram(pages, ubuf->pagecount, -1);
> - kfree(pages);
> + kvfree(pages);
> if (!vaddr)
> return -EINVAL;
>
> @@ -189,8 +189,8 @@ static void release_udmabuf(struct dma_buf *buf)
> put_sg_table(dev, ubuf->sg, DMA_BIDIRECTIONAL);
>
> unpin_all_folios(&ubuf->unpin_list);
> - kfree(ubuf->offsets);
> - kfree(ubuf->folios);
> + kvfree(ubuf->offsets);
> + kvfree(ubuf->folios);
> kfree(ubuf);
> }
>
> @@ -315,14 +315,14 @@ static long udmabuf_create(struct miscdevice
> *device,
> if (!ubuf->pagecount)
> goto err;
>
> - ubuf->folios = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->folios),
> - GFP_KERNEL);
> + ubuf->folios = kvmalloc_array(ubuf->pagecount, sizeof(*ubuf-
> >folios),
> + GFP_KERNEL);
> if (!ubuf->folios) {
> ret = -ENOMEM;
> goto err;
> }
> - ubuf->offsets = kcalloc(ubuf->pagecount, sizeof(*ubuf->offsets),
> - GFP_KERNEL);
> + ubuf->offsets =
> + kvcalloc(ubuf->pagecount, sizeof(*ubuf->offsets),
No strong opinion, but I'd prefer to keep the kvcalloc on the same line.
Regardless,
Acked-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
> GFP_KERNEL);
> if (!ubuf->offsets) {
> ret = -ENOMEM;
> goto err;
> @@ -336,7 +336,7 @@ static long udmabuf_create(struct miscdevice
> *device,
> goto err;
>
> pgcnt = list[i].size >> PAGE_SHIFT;
> - folios = kmalloc_array(pgcnt, sizeof(*folios), GFP_KERNEL);
> + folios = kvmalloc_array(pgcnt, sizeof(*folios), GFP_KERNEL);
> if (!folios) {
> ret = -ENOMEM;
> goto err;
> @@ -346,7 +346,7 @@ static long udmabuf_create(struct miscdevice
> *device,
> ret = memfd_pin_folios(memfd, list[i].offset, end,
> folios, pgcnt, &pgoff);
> if (ret <= 0) {
> - kfree(folios);
> + kvfree(folios);
> if (!ret)
> ret = -EINVAL;
> goto err;
> @@ -375,7 +375,7 @@ static long udmabuf_create(struct miscdevice
> *device,
> }
> }
>
> - kfree(folios);
> + kvfree(folios);
> fput(memfd);
> memfd = NULL;
> }
> @@ -391,8 +391,8 @@ static long udmabuf_create(struct miscdevice
> *device,
> if (memfd)
> fput(memfd);
> unpin_all_folios(&ubuf->unpin_list);
> - kfree(ubuf->offsets);
> - kfree(ubuf->folios);
> + kvfree(ubuf->offsets);
> + kvfree(ubuf->folios);
> kfree(ubuf);
> return ret;
> }
> --
> 2.45.2
