From: Kevin Hao
> Sent: 21 January 2021 07:09
>
> The octeontx2 hardware needs the buffer to be 128 byte aligned.
> But in the current implementation of napi_alloc_frag(), it can't
> guarantee the return address is 128 byte aligned even the request size
> is a multiple of 128 bytes, so we have to request an extra 128 bytes and
> use the PTR_ALIGN() to make sure that the buffer is aligned correctly.
>
> Fixes: 7a36e4918e30 ("octeontx2-pf: Use the napi_alloc_frag() to alloc the
> pool buffers")
> Reported-by: Subbaraya Sundeep <[email protected]>
> Signed-off-by: Kevin Hao <[email protected]>
> ---
> drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> index bdfa2e293531..5ddedc3b754d 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> @@ -488,10 +488,11 @@ dma_addr_t __otx2_alloc_rbuf(struct otx2_nic *pfvf,
> struct otx2_pool *pool)
> dma_addr_t iova;
> u8 *buf;
>
> - buf = napi_alloc_frag(pool->rbsize);
> + buf = napi_alloc_frag(pool->rbsize + OTX2_ALIGN);
> if (unlikely(!buf))
> return -ENOMEM;
>
> + buf = PTR_ALIGN(buf, OTX2_ALIGN);
> iova = dma_map_single_attrs(pfvf->dev, buf, pool->rbsize,
> DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
> if (unlikely(dma_mapping_error(pfvf->dev, iova))) {
> --
> 2.29.2
Doesn't that break the 'free' code ?
Surely it needs the original pointer.
It isn't obvious that page_frag_free() it correct when the
allocator is napi_alloc_frag() either.
I'd have thought it ought to be returned to the pool.
David
-
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