This is a note to let you know that I've just added the patch titled
udmabuf: change folios array from kmalloc to kvmalloc
to the 6.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
udmabuf-change-folios-array-from-kmalloc-to-kvmalloc.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 403550d91ae6e3e1d6f0acbcc2f31b8ab630b4f6
Author: Huan Yang <link@xxxxxxxx>
Date: Wed Sep 18 10:52:25 2024 +0800
udmabuf: change folios array from kmalloc to kvmalloc
[ Upstream commit 1c0844c6184e658064e14c4335885785ad3bf84b ]
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>
Acked-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240918025238.2957823-3-link@xxxxxxxx
Stable-dep-of: 18d7de823b71 ("udmabuf: fix vmap_udmabuf error page set")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 047c3cd2cefff..bc94c194e172d 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -80,7 +80,7 @@ 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;
@@ -88,7 +88,7 @@ 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;
@@ -196,8 +196,8 @@ 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);
}
@@ -322,14 +322,14 @@ 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),
+ GFP_KERNEL);
if (!ubuf->offsets) {
ret = -ENOMEM;
goto err;
@@ -343,7 +343,7 @@ 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;
@@ -353,7 +353,7 @@ 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;
@@ -382,7 +382,7 @@ static long udmabuf_create(struct miscdevice *device,
}
}
- kfree(folios);
+ kvfree(folios);
fput(memfd);
memfd = NULL;
}
@@ -398,8 +398,8 @@ 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;
}
