Messages in this thread | | | Date | Sun, 17 Mar 2024 14:14:02 -0600 | Subject | Re: [PATCH] perf/x86/rapl: Prefer struct_size over open coded arithmetic | From | "Gustavo A. R. Silva" <> |
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On 3/17/24 10:44, Erick Archer wrote: > This is an effort to get rid of all multiplications from allocation > functions in order to prevent integer overflows [1][2]. > > As the "rapl_pmus" variable is a pointer to "struct rapl_pmus" and > this structure ends in a flexible array: > > struct rapl_pmus { > [...] > struct rapl_pmu *pmus[] __counted_by(maxdie); > }; > > the preferred way in the kernel is to use the struct_size() helper to > do the arithmetic instead of the calculation "size + count * size" in > the kzalloc() function. > > This way, the code is more readable and safer. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] > Link: https://github.com/KSPP/linux/issues/160 [2] > Signed-off-by: Erick Archer <erick.archer@gmx.com> LGTM:
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Thanks! -- Gustavo
> --- > arch/x86/events/rapl.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c > index fb2b1961e5a3..8ef08b5d55a7 100644 > --- a/arch/x86/events/rapl.c > +++ b/arch/x86/events/rapl.c > @@ -675,10 +675,8 @@ static const struct attribute_group *rapl_attr_update[] = { > static int __init init_rapl_pmus(void) > { > int maxdie = topology_max_packages() * topology_max_dies_per_package(); > - size_t size; > > - size = sizeof(*rapl_pmus) + maxdie * sizeof(struct rapl_pmu *); > - rapl_pmus = kzalloc(size, GFP_KERNEL); > + rapl_pmus = kzalloc(struct_size(rapl_pmus, pmus, maxdie), GFP_KERNEL); > if (!rapl_pmus) > return -ENOMEM; > > -- > 2.25.1 > >
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