See below. Code cleanups accepted for next revision.
On 07/11/2018 11:00 AM, Naveen N. Rao wrote:
> Michael Bringmann wrote:
>> powerpc/cpu: Modify dlpar_cpu_add and dlpar_cpu_remove to allow the
>> skipping of DRC index acquire or release operations during the CPU
>> add or remove operations. This is intended to support subsequent
>> changes to provide a 'CPU readd' operation.
>>
>> Signed-off-by: Michael Bringmann <m...@linux.vnet.ibm.com>
>> ---
>> Changes in patch:
>> -- Move new validity check added to pseries_smp_notifier
>> to another patch
>> ---
>> arch/powerpc/platforms/pseries/hotplug-cpu.c | 68
>> +++++++++++++++-----------
>> 1 file changed, 39 insertions(+), 29 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> index 6ef77ca..3632db2 100644
>> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> @@ -432,7 +432,7 @@ static bool valid_cpu_drc_index(struct device_node
>> *parent, u32 drc_index)
>> return found;
>> }
>>
>> -static ssize_t dlpar_cpu_add(u32 drc_index)
>> +static ssize_t dlpar_cpu_add(u32 drc_index, bool acquire_drc)
>> {
>> struct device_node *dn, *parent;
>> int rc, saved_rc;
>> @@ -457,19 +457,22 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>> return -EINVAL;
>> }
>>
>> - rc = dlpar_acquire_drc(drc_index);
>> - if (rc) {
>> - pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
>> - rc, drc_index);
>> - of_node_put(parent);
>> - return -EINVAL;
>> + if (acquire_drc) {
>> + rc = dlpar_acquire_drc(drc_index);
>> + if (rc) {
>> + pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
>> + rc, drc_index);
>> + of_node_put(parent);
>> + return -EINVAL;
>> + }
>> }
>>
>> dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
>> if (!dn) {
>> pr_warn("Failed call to configure-connector, drc index: %x\n",
>> drc_index);
>> - dlpar_release_drc(drc_index);
>> + if (acquire_drc)
>> + dlpar_release_drc(drc_index);
>> of_node_put(parent);
>> return -EINVAL;
>> }
>> @@ -484,8 +487,9 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>> pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n",
>> dn->name, rc, drc_index);
>>
>> - rc = dlpar_release_drc(drc_index);
>> - if (!rc)
>> + if (acquire_drc)
>> + rc = dlpar_release_drc(drc_index);
>> + if (!rc || acquire_drc)
>> dlpar_free_cc_nodes(dn);
>
> (!rc) can only be true if acquire_drc is true, so we seem to be only invoking
> dlpar_free_cc_nodes() if acquire_drc is true. Would it be better to frame
> that condition in this manner:
>
> if (acquire_drc) {
> rc = dlpar_release_drc(drc_index):
> if (!rc)
> dlpar_free_cc_nodes(dn);
> }
>
Okay.
>>
>> return saved_rc;
>> @@ -498,7 +502,7 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>> dn->name, rc, drc_index);
>>
>> rc = dlpar_detach_node(dn);
>> - if (!rc)
>> + if (!rc && acquire_drc)
>> dlpar_release_drc(drc_index);
>>
>> return saved_rc;
>> @@ -566,7 +570,8 @@ static int dlpar_offline_cpu(struct device_node *dn)
>>
>> }
>>
>> -static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
>> +static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index,
>> + bool release_drc)
>> {
>> int rc;
>>
>> @@ -579,12 +584,14 @@ static ssize_t dlpar_cpu_remove(struct device_node
>> *dn, u32 drc_index)
>> return -EINVAL;
>> }
>>
>> - rc = dlpar_release_drc(drc_index);
>> - if (rc) {
>> - pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
>> - drc_index, dn->name, rc);
>> - dlpar_online_cpu(dn);
>> - return rc;
>> + if (release_drc) {
>> + rc = dlpar_release_drc(drc_index);
>> + if (rc) {
>> + pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
>> + drc_index, dn->name, rc);
>> + dlpar_online_cpu(dn);
>> + return rc;
>> + }
>> }
>>
>> rc = dlpar_detach_node(dn);
>> @@ -593,7 +600,10 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn,
>> u32 drc_index)
>>
>> pr_warn("Failed to detach CPU %s, rc: %d", dn->name, rc);
>>
>> - rc = dlpar_acquire_drc(drc_index);
>> + if (release_drc)
>> + rc = dlpar_acquire_drc(drc_index);
>> + else
>> + rc = 0;
>> if (!rc)
>> dlpar_online_cpu(dn);
>
> Here, we seem to want to invoke dlpar_online_cpu() unconditionally if
> release_drc is false. So, to make that explicit, would it be better to frame
> that as:
> if (release_drc)
> rc = dlpar_acquire_drc(drc_index);
> if (!release_drc || !rc)
> dlpar_online_cpu(dn);
>
> - Naveen
Okay.
>
>>
>> @@ -622,7 +632,7 @@ static struct device_node *cpu_drc_index_to_dn(u32
>> drc_index)
>> return dn;
>> }
>>
>> -static int dlpar_cpu_remove_by_index(u32 drc_index)
>> +static int dlpar_cpu_remove_by_index(u32 drc_index, bool release_drc)
>> {
>> struct device_node *dn;
>> int rc;
>> @@ -634,7 +644,7 @@ static int dlpar_cpu_remove_by_index(u32 drc_index)
>> return -ENODEV;
>> }
>>
>> - rc = dlpar_cpu_remove(dn, drc_index);
>> + rc = dlpar_cpu_remove(dn, drc_index, release_drc);
>> of_node_put(dn);
>> return rc;
>> }
>> @@ -699,7 +709,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
>> }
>>
>> for (i = 0; i < cpus_to_remove; i++) {
>> - rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
>> + rc = dlpar_cpu_remove_by_index(cpu_drcs[i], true);
>> if (rc)
>> break;
>>
>> @@ -710,7 +720,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
>> pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
>>
>> for (i = 0; i < cpus_removed; i++)
>> - dlpar_cpu_add(cpu_drcs[i]);
>> + dlpar_cpu_add(cpu_drcs[i], true);
>>
>> rc = -EINVAL;
>> } else {
>> @@ -780,7 +790,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
>> }
>>
>> for (i = 0; i < cpus_to_add; i++) {
>> - rc = dlpar_cpu_add(cpu_drcs[i]);
>> + rc = dlpar_cpu_add(cpu_drcs[i], true);
>> if (rc)
>> break;
>>
>> @@ -791,7 +801,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
>> pr_warn("CPU hot-add failed, removing any added CPUs\n");
>>
>> for (i = 0; i < cpus_added; i++)
>> - dlpar_cpu_remove_by_index(cpu_drcs[i]);
>> + dlpar_cpu_remove_by_index(cpu_drcs[i], true);
>>
>> rc = -EINVAL;
>> } else {
>> @@ -817,7 +827,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
>> if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
>> rc = dlpar_cpu_remove_by_count(count);
>> else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
>> - rc = dlpar_cpu_remove_by_index(drc_index);
>> + rc = dlpar_cpu_remove_by_index(drc_index, true);
>> else
>> rc = -EINVAL;
>> break;
>> @@ -825,7 +835,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
>> if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
>> rc = dlpar_cpu_add_by_count(count);
>> else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
>> - rc = dlpar_cpu_add(drc_index);
>> + rc = dlpar_cpu_add(drc_index, true);
>> else
>> rc = -EINVAL;
>> break;
>> @@ -850,7 +860,7 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t
>> count)
>> if (rc)
>> return -EINVAL;
>>
>> - rc = dlpar_cpu_add(drc_index);
>> + rc = dlpar_cpu_add(drc_index, true);
>>
>> return rc ? rc : count;
>> }
>> @@ -871,7 +881,7 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t
>> count)
>> return -EINVAL;
>> }
>>
>> - rc = dlpar_cpu_remove(dn, drc_index);
>> + rc = dlpar_cpu_remove(dn, drc_index, true);
>> of_node_put(dn);
>>
>> return rc ? rc : count;
>>
>>
>
>
--
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line 363-5196
External: (512) 286-5196
Cell: (512) 466-0650
m...@linux.vnet.ibm.com
