diff options
| author |   Miles Chen <miles.chen@mediatek.com> | 2022-01-14 14:07:30 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-15 16:30:29 +0200 |
| commit | 04a536bfbd0f885338eecc2a4503dfca50ac94dd (patch) | |
| tree | 146a188e565085726087865260ed8d67719065ba /include/linux/gfp.h | |
| parent | mm: drop node from alloc_pages_vma (diff) | |
| download | wireguard-linux-04a536bfbd0f885338eecc2a4503dfca50ac94dd.tar.xz wireguard-linux-04a536bfbd0f885338eecc2a4503dfca50ac94dd.zip | |
include/linux/gfp.h: further document GFP_DMA32
kmalloc(..., GFP_DMA32) does not return DMA32 memory because the DMA32
kmalloc cache array is not implemented. (Reason: there is no such user
in kernel).
Put a short comment about this so people can understand this by reading
the comment.
[1] https://lists.linuxfoundation.org/pipermail/iommu/2018-December/031696.html
Link: https://lkml.kernel.org/r/20211207093610.6406-1-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/gfp.h')
| -rw-r--r-- | include/linux/gfp.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 78b58448f796..80f63c862be5 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -302,7 +302,9 @@ struct vm_area_struct; * lowest zone as a type of emergency reserve. * * %GFP_DMA32 is similar to %GFP_DMA except that the caller requires a 32-bit - * address. + * address. Note that kmalloc(..., GFP_DMA32) does not return DMA32 memory + * because the DMA32 kmalloc cache array is not implemented. + * (Reason: there is no such user in kernel). * * %GFP_HIGHUSER is for userspace allocations that may be mapped to userspace, * do not need to be directly accessible by the kernel but that cannot |