RE: [PATCH 07/12] igb: Proactively round up to kmalloc bucket size

[Ruhl, Michael J]

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>From: dri-devel <dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of
>Kees Cook
>Sent: Wednesday, September 21, 2022 11:10 PM
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>Subject: [PATCH 07/12] igb: Proactively round up to kmalloc bucket size
>
>Instead of having a mismatch between the requested allocation size and
>the actual kmalloc bucket size, which is examined later via ksize(),
>round up proactively so the allocation is explicitly made for the full
>size, allowing the compiler to correctly reason about the resulting size
>of the buffer through the existing __alloc_size() hint.
>
>Cc: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>
>Cc: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
>Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
>Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
>Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
>Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
>Cc: intel-wired-lan@xxxxxxxxxxxxxxxx
>Cc: netdev@xxxxxxxxxxxxxxx
>Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>---
> drivers/net/ethernet/intel/igb/igb_main.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/drivers/net/ethernet/intel/igb/igb_main.c
>b/drivers/net/ethernet/intel/igb/igb_main.c
>index 2796e81d2726..4d70ee5b0f79 100644
>--- a/drivers/net/ethernet/intel/igb/igb_main.c
>+++ b/drivers/net/ethernet/intel/igb/igb_main.c
>@@ -1196,6 +1196,7 @@ static int igb_alloc_q_vector(struct igb_adapter
>*adapter,
>
> 	ring_count = txr_count + rxr_count;
> 	size = struct_size(q_vector, ring, ring_count);
>+	size = kmalloc_size_roundup(size);

why not:

	size = kmalloc_size_roundup(struct_size(q_vector, ring, ring_count));

?

m
> 	/* allocate q_vector and rings */
> 	q_vector = adapter->q_vector[v_idx];
>--
>2.34.1