Re: [RFC PATCH v3 08/10] EDAC/amd64: Gather hardware information early

Borislav Petkov
2019-08-29T09:22:50Z

On Thu, Aug 22, 2019 at 12:00:02AM +0000, Ghannam, Yazen wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
>
> Split out gathering hardware information from init_one_instance() into a
> separate function get_hardware_info().
>
> This is necessary so that the information can be cached earlier and used
> to check if memory is populated and if ECC is enabled on a node.
>
> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
> drivers/edac/amd64_edac.c | 76 +++++++++++++++++++++++----------------
> 1 file changed, 45 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
> index 4d1e6daa7ec4..84832771dec0 100644
> --- a/drivers/edac/amd64_edac.c
> +++ b/drivers/edac/amd64_edac.c
> @@ -3405,34 +3405,17 @@ static void compute_num_umcs(void)
> edac_dbg(1, "Number of UMCs: %x", num_umcs);
> }
>
> -static int init_one_instance(unsigned int nid)
> +static int get_hardware_info(struct amd64_pvt *pvt,
> + struct amd64_family_type *fam_type)
> {
> - struct pci_dev *F3 = node_to_amd_nb(nid)->misc;
> - struct amd64_family_type *fam_type = NULL;
> - struct mem_ctl_info *mci = NULL;
> - struct edac_mc_layer layers[2];
> - struct amd64_pvt *pvt = NULL;
> u16 pci_id1, pci_id2;
> - int err = 0, ret;
> -
> - ret = -ENOMEM;
> - pvt = kzalloc(sizeof(struct amd64_pvt), GFP_KERNEL);
> - if (!pvt)
> - goto err_ret;
> -
> - pvt->mc_node_id = nid;
> - pvt->F3 = F3;
> -
> - ret = -EINVAL;
> - fam_type = per_family_init(pvt);
> - if (!fam_type)
> - goto err_free;
> + int ret = -EINVAL;
>
> if (pvt->fam >= 0x17) {
> pvt->umc = kcalloc(num_umcs, sizeof(struct amd64_umc), GFP_KERNEL);

Yeah, a get_hardware_info() function which does an allocation of that
struct amd64_umc on => F17 which is only 20 bytes. Just add it into the
pvt struct:

struct amd64_pvt {
...
struct amd64_umc umc; /* UMC registers */
};

and be done with it. This should simplify the code flow here a bit and
20 bytes more per pvt is not a big deal.

And I know we do test "if (pvt->umc)" in a bunch of places but that can
be replaced with a "if (pvt->fam >= 0x17)" test which is equivalent.

And that conversion should be a single patch.

> if (!pvt->umc) {
> ret = -ENOMEM;
> - goto err_free;
> + goto err_ret;
> }
>
> pci_id1 = fam_type->f0_id;
> @@ -3442,18 +3425,34 @@ static int init_one_instance(unsigned int nid)
> pci_id2 = fam_type->f2_id;
> }
>
> - err = reserve_mc_sibling_devs(pvt, pci_id1, pci_id2);
> - if (err)
> + ret = reserve_mc_sibling_devs(pvt, pci_id1, pci_id2);
> + if (ret)
> goto err_post_init;
>
> read_mc_regs(pvt);
>
> + return 0;
> +
> +err_post_init:
> + if (pvt->fam >= 0x17)
> + kfree(pvt->umc);
> +
> +err_ret:
> + return ret;
> +}
> +
> +static int init_one_instance(struct amd64_pvt *pvt,
> + struct amd64_family_type *fam_type)

Yeah, that fam_type can be made global. No need to hand it around in
functions since it is going to be a single struct per system. Do that in
another, separate patch please.

After you've done those things, this patch would become a lot simpler.

Thx.

--
Regards/Gruss,
Boris.

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