powerpc/pseries: break early in dlpar_memory_add_by_count() loops

After a successful dlpar_add_lmb() call the LMB is marked as reserved.
Later on, depending whether we added enough LMBs or not, we rely on
the marked LMBs to see which ones might need to be removed, and we
remove the reservation of all of them.

These are done in for_each_drmem_lmb() loops without any break
condition. This means that we're going to check all LMBs of the partition
even after going through all the reserved ones.

This patch adds break conditions in both loops to avoid this. The
'lmbs_added' variable was renamed to 'lmbs_reserved', and it's now
being decremented each time a lmb reservation is removed, indicating
if there are still marked LMBs to be processed.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210622133923.295373-3-danielhb413@gmail.com

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 28a7fd9..c0a03e1 100644 (file)
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -673,7 +673,7 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
 {
        struct drmem_lmb *lmb;
        int lmbs_available = 0;
-       int lmbs_added = 0;
+       int lmbs_reserved = 0;
        int rc;
 
        pr_info("Attempting to hot-add %d LMB(s)\n", lmbs_to_add);
@@ -714,13 +714,12 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
                 * requested LMBs cannot be added.
                 */
                drmem_mark_lmb_reserved(lmb);
-
-               lmbs_added++;
-               if (lmbs_added == lmbs_to_add)
+               lmbs_reserved++;
+               if (lmbs_reserved == lmbs_to_add)
                        break;
        }
 
-       if (lmbs_added != lmbs_to_add) {
+       if (lmbs_reserved != lmbs_to_add) {
                pr_err("Memory hot-add failed, removing any added LMBs\n");
 
                for_each_drmem_lmb(lmb) {
@@ -735,6 +734,10 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
                                dlpar_release_drc(lmb->drc_index);
 
                        drmem_remove_lmb_reservation(lmb);
+                       lmbs_reserved--;
+
+                       if (lmbs_reserved == 0)
+                               break;
                }
                rc = -EINVAL;
        } else {
@@ -745,6 +748,10 @@ static int dlpar_memory_add_by_count(u32 lmbs_to_add)
                        pr_debug("Memory at %llx (drc index %x) was hot-added\n",
                                 lmb->base_addr, lmb->drc_index);
                        drmem_remove_lmb_reservation(lmb);
+                       lmbs_reserved--;
+
+                       if (lmbs_reserved == 0)
+                               break;
                }
                rc = 0;
        }