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powerpc/pseries: remove obsolete memory hotplug DT notifier code

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pseries_update_drconf_memory() runs from a DT notifier in response to
an update to the ibm,dynamic-memory property of the
/ibm,dynamic-reconfiguration-memory node. This property is an older
less compact format than the ibm,dynamic-memory-v2 property used in
most currently supported firmwares. There has never been an equivalent
function for the v2 property.

pseries_update_drconf_memory() compares the 'assigned' flag for each
LMB in the old vs new properties and adds or removes the block
accordingly. However it appears to be of no actual utility:

* Partition suspension and PRRNs are specified only to change LMBs'
  NUMA affinity information. This notifier should be a no-op for those
  scenarios since the assigned flags should not change.

* The memory hotplug/DLPAR path has a hack which short-circuits
  execution of the notifier:
     dlpar_memory()
        ...
        rtas_hp_event = true;
        drmem_update_dt()
           of_update_property()
              pseries_memory_notifier()
                 pseries_update_drconf_memory()
                    if (rtas_hp_event) return;

So this code only makes sense as a relic of the time when more of the
DLPAR workflow took place in user space. I don't see a purpose for it
now.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612051238.1007764-19-nathanl@linux.ibm.com
This commit is contained in:
Nathan Lynch
2020-06-12 00:12:38 -05:00
committed by Michael Ellerman
parent 38c392cef1
commit e978a3ccaa
1 changed files with 1 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
arch/powerpc/platforms/pseries/hotplug-memory.c
View File

@@ -22,8 +22,6 @@
#include <asm/drmem.h>
#include "pseries.h"
static bool rtas_hp_event;
unsigned long pseries_memory_block_size(void)
{
struct device_node *np;
@@ -871,11 +869,8 @@ int dlpar_memory(struct pseries_hp_errorlog *hp_elog)
break;
}
if (!rc) {
rtas_hp_event = true;
if (!rc)
rc = drmem_update_dt();
rtas_hp_event = false;
}
unlock_device_hotplug();
return rc;
@@ -911,60 +906,6 @@ static int pseries_add_mem_node(struct device_node *np)
return (ret < 0) ? -EINVAL : 0;
}
static int pseries_update_drconf_memory(struct of_reconfig_data *pr)
{
struct of_drconf_cell_v1 *new_drmem, *old_drmem;
unsigned long memblock_size;
u32 entries;
__be32 *p;
int i, rc = -EINVAL;
if (rtas_hp_event)
return 0;
memblock_size = pseries_memory_block_size();
if (!memblock_size)
return -EINVAL;
if (!pr->old_prop)
return 0;
p = (__be32 *) pr->old_prop->value;
if (!p)
return -EINVAL;
/* The first int of the property is the number of lmb's described
* by the property. This is followed by an array of of_drconf_cell
* entries. Get the number of entries and skip to the array of
* of_drconf_cell's.
*/
entries = be32_to_cpu(*p++);
old_drmem = (struct of_drconf_cell_v1 *)p;
p = (__be32 *)pr->prop->value;
p++;
new_drmem = (struct of_drconf_cell_v1 *)p;
for (i = 0; i < entries; i++) {
if ((be32_to_cpu(old_drmem[i].flags) & DRCONF_MEM_ASSIGNED) &&
(!(be32_to_cpu(new_drmem[i].flags) & DRCONF_MEM_ASSIGNED))) {
rc = pseries_remove_memblock(
be64_to_cpu(old_drmem[i].base_addr),
memblock_size);
break;
} else if ((!(be32_to_cpu(old_drmem[i].flags) &
DRCONF_MEM_ASSIGNED)) &&
(be32_to_cpu(new_drmem[i].flags) &
DRCONF_MEM_ASSIGNED)) {
rc = memblock_add(be64_to_cpu(old_drmem[i].base_addr),
memblock_size);
rc = (rc < 0) ? -EINVAL : 0;
break;
}
}
return rc;
}
static int pseries_memory_notifier(struct notifier_block *nb,
unsigned long action, void *data)
{
@@ -978,10 +919,6 @@ static int pseries_memory_notifier(struct notifier_block *nb,
case OF_RECONFIG_DETACH_NODE:
err = pseries_remove_mem_node(rd->dn);
break;
case OF_RECONFIG_UPDATE_PROPERTY:
if (!strcmp(rd->prop->name, "ibm,dynamic-memory"))
err = pseries_update_drconf_memory(rd);
break;
}
return notifier_from_errno(err);
}