Re: [PATCH] ata: ahci_tegra: remove kcalloc

[Rosen Penev]

On Wed, Mar 25, 2026 at 3:17 AM Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
>
>
> On 25/03/2026 07:30, Niklas Cassel wrote:
> > Hello Rosen,
> >
> > subject is a bit misleading:
> > "remove kcalloc"
> > you are removing devm_kcalloc(), so device managed.
> >
> >
> > On Tue, Mar 24, 2026 at 02:16:29PM -0700, Rosen Penev wrote:
> >> Combine allocations into one by using a flexible array member.
> >>
> >> Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
> >> ---
> >>   drivers/ata/ahci_tegra.c | 15 ++++++---------
> >>   1 file changed, 6 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/ata/ahci_tegra.c b/drivers/ata/ahci_tegra.c
> >> index 44584eed6374..5972fe04ff3f 100644
> >> --- a/drivers/ata/ahci_tegra.c
> >> +++ b/drivers/ata/ahci_tegra.c
> >> @@ -175,8 +175,9 @@ struct tegra_ahci_priv {
> >>      struct reset_control       *sata_cold_rst;
> >>      /* Needs special handling, cannot use ahci_platform */
> >>      struct clk                 *sata_clk;
> >> -    struct regulator_bulk_data *supplies;
> >>      const struct tegra_ahci_soc *soc;
> >> +
> >> +    struct regulator_bulk_data supplies[];
> >
> > Personally I'm not a big fan of flexible array members, as there can be
> > only one. And if you use it you want to use counted_by().
> >
> > Yes, there are two device managed allocations. But is that so bad?
> >
> > Since it is device managed, it will get freed on device removal anyway.
>
> FWIW I am not a big fan of this either. It is not an obvious bang for
> the buck for me. The one downside I see is that it does leave the door
> open for someone accidentally putting another variable after the
> flexible array member. Yes we should catch this in review, but there
> really should be at least a comment saying this must be the final member
> of the struct.
That will eventually become a compile time error. Currently there are
a bunch of those cases that need to get fixed before that happens.
Hardening people are working on it.
>
> Jon
>
> --
> nvpublic
>