From: Nathan Lynch <nathanl@linux.ibm.com>
To: Tyrel Datwyler <tyreld@linux.ibm.com>
Cc: bhelgaas@google.com, linux-pci@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [RFC PATCH 1/9] powerpc/pseries: add cpu DLPAR support for drc-info property
Date: Thu, 10 Oct 2019 13:56:28 -0500 [thread overview]
Message-ID: <871rvkjuoz.fsf@linux.ibm.com> (raw)
In-Reply-To: <1569910334-5972-2-git-send-email-tyreld@linux.ibm.com>
Hi Tyrel,
Tyrel Datwyler <tyreld@linux.ibm.com> writes:
> +static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
> +{
> + const __be32 *indexes;
> + int i;
> +
> + if (of_find_property(parent, "ibm,drc-info", NULL))
> + return drc_info_valid_index(parent, drc_index);
> +
> + indexes = of_get_property(parent, "ibm,drc-indexes", NULL);
> + if (!indexes)
> + return false;
> +
> + for (i = 0; i < indexes[0]; i++) {
should this be:
for (i = 0; i < be32_to_cpu(indexes[0]); i++) {
?
> + if (be32_to_cpu(indexes[i + 1]) == drc_index)
> + return true;
> + }
> +
> + return false;
> }
It looks like this rewrites valid_cpu_drc_index()'s existing code for
parsing ibm,drc-indexes but I don't see the need for this.
This patch would be easier to review if that were dropped or split out.
>
> static ssize_t dlpar_cpu_add(u32 drc_index)
> @@ -720,8 +756,11 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
> static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
> {
> struct device_node *parent;
> + struct property *info;
> + const __be32 *indexes;
> int cpus_found = 0;
> - int index, rc;
> + int i, j;
> + u32 drc_index;
>
> parent = of_find_node_by_path("/cpus");
> if (!parent) {
> @@ -730,24 +769,46 @@ static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
> return -1;
> }
>
> - /* Search the ibm,drc-indexes array for possible CPU drcs to
> - * add. Note that the format of the ibm,drc-indexes array is
> - * the number of entries in the array followed by the array
> - * of drc values so we start looking at index = 1.
> - */
> - index = 1;
> - while (cpus_found < cpus_to_add) {
> - u32 drc;
> + info = of_find_property(parent, "ibm,drc-info", NULL);
> + if (info) {
> + struct of_drc_info drc;
> + const __be32 *value;
> + int count;
>
> - rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
> - index++, &drc);
> - if (rc)
> - break;
> + value = of_prop_next_u32(info, NULL, &count);
> + if (value)
> + value++;
>
> - if (dlpar_cpu_exists(parent, drc))
> - continue;
> + for (i = 0; i < count; i++) {
> + of_read_drc_info_cell(&info, &value, &drc);
> + if (strncmp(drc.drc_type, "CPU", 3))
> + break;
> +
> + for (j = 0; j < drc.num_sequential_elems; j++) {
> + drc_index = drc.drc_index_start + (drc.sequential_inc * j);
> +
> + if (dlpar_cpu_exists(parent, drc_index))
> + continue;
>
> - cpu_drcs[cpus_found++] = drc;
> + cpu_drcs[cpus_found++] = drc_index;
I am failing to see how this loop is limited by the cpus_to_add
parameter as it was before this change. It looks like this will overflow
the cpu_drcs array when cpus_to_add is less than the number of cpus
found.
As an aside I don't understand how the add_by_count()/dlpar_cpu_exists()
algorithm could be correct as it currently stands. It seems to pick the
first X indexes for which a corresponding cpu node is absent, but that
set of indexes does not necessarily match the set that is available to
configure. Something to address separately I suppose.
> + }
> + }
> + } else {
> + indexes = of_get_property(parent, "ibm,drc-indexes", NULL);
> +
> + /* Search the ibm,drc-indexes array for possible CPU drcs to
> + * add. Note that the format of the ibm,drc-indexes array is
> + * the number of entries in the array followed by the array
> + * of drc values so we start looking at index = 1.
> + */
> + for (i = 1; i < indexes[0]; i++) {
> + drc_index = be32_to_cpu(indexes[i]);
> +
> + if (dlpar_cpu_exists(parent, drc_index))
> + continue;
> +
> + cpu_drcs[cpus_found++] = drc_index;
> + }
> }
As above, not sure why this was rewritten, and similar comments as
before apply.
next prev parent reply other threads:[~2019-10-10 18:58 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 6:12 [RFC PATCH 0/9] Fixes and Enablement of ibm,drc-info property Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 1/9] powerpc/pseries: add cpu DLPAR support for drc-info property Tyrel Datwyler
2019-10-10 18:56 ` Nathan Lynch [this message]
2019-10-30 23:35 ` Tyrel Datwyler
2019-10-31 17:14 ` Nathan Lynch
2019-10-01 6:12 ` [RFC PATCH 2/9] powerpc/pseries: fix bad drc_index_start value parsing of drc-info entry Tyrel Datwyler
2019-10-10 19:04 ` Nathan Lynch
2019-10-10 20:16 ` powerpc/405GP, cuImage and PCI support Carlo Pisani
2019-10-31 0:15 ` [RFC PATCH 2/9] powerpc/pseries: fix bad drc_index_start value parsing of drc-info entry Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 3/9] powerpc/pseries: fix drc-info mappings of logical cpus to drc-index Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 4/9] PCI: rpaphp: fix up pointer to first drc-info entry Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 5/9] PCI: rpaphp: don't rely on firmware feature to imply drc-info support Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 6/9] PCI: rpaphp: add drc-info support for hotplug slot registration Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 7/9] PCI: rpaphp: annotate and correctly byte swap DRC properties Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 8/9] PCI: rpaphp: correctly match ibm, my-drc-index to drc-name when using drc-info Tyrel Datwyler
2019-10-01 6:12 ` [RFC PATCH 9/9] powerpc: Enable support for ibm,drc-info property Tyrel Datwyler
2019-10-01 20:02 ` [RFC PATCH 0/9] Fixes and Enablement of " Bjorn Helgaas
2019-10-31 0:15 ` Tyrel Datwyler
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