powerpc/pseries: fail quicker in dlpar_memory_add_by_ic()

The validation done at the start of dlpar_memory_add_by_ic() is an all
of nothing scenario - if any LMBs in the range is marked as RESERVED we
can fail right away.

We then can remove the 'lmbs_available' var and its check with
'lmbs_to_add' since the whole LMB range was already validated in the
previous step.
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210622133923.295373-4-danielhb413@gmail.com

arch/powerpc/platforms/pseries/hotplug-memory.c

@@ -796,7 +796,6 @@ static int dlpar_memory_add_by_index(u32 drc_index)
 static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
 {
 	struct drmem_lmb *lmb, *start_lmb, *end_lmb;
-	int lmbs_available = 0;
 	int rc;
 
 	pr_info("Attempting to hot-add %u LMB(s) at index %x\n",
@@ -811,15 +810,14 @@ static int dlpar_memory_add_by_ic(u32 lmbs_to_add, u32 drc_index)
 
 	/* Validate that the LMBs in this range are not reserved */
 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
-		if (lmb->flags & DRCONF_MEM_RESERVED)
-			break;
-
-		lmbs_available++;
+		/* Fail immediately if the whole range can't be hot-added */
+		if (lmb->flags & DRCONF_MEM_RESERVED) {
+			pr_err("Memory at %llx (drc index %x) is reserved\n",
+					lmb->base_addr, lmb->drc_index);
+			return -EINVAL;
+		}
 	}
 
-	if (lmbs_available < lmbs_to_add)
-		return -EINVAL;
-
 	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {
 		if (lmb->flags & DRCONF_MEM_ASSIGNED)
 			continue;