powerpc: pci-ioda: use bitmap_alloc() in pnv_ioda_pick_m64_pe()

Use the dedicated bitmap_alloc() in pnv_ioda_pick_m64_pe() and drop
some housekeeping code.

Because pe_alloc is local, annotate it with __free() and get rid of
the explicit kfree() calls.

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250814190936.381346-2-yury.norov@gmail.com

Author: YuryNorov

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -292,18 +292,16 @@ static void pnv_ioda_reserve_m64_pe(struct pci_bus *bus,
 
 static struct pnv_ioda_pe *pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
 {
+	unsigned long *pe_alloc __free(bitmap) = NULL;
 	struct pnv_phb *phb = pci_bus_to_pnvhb(bus);
 	struct pnv_ioda_pe *master_pe, *pe;
-	unsigned long size, *pe_alloc;
 	int i;
 
 	/* Root bus shouldn't use M64 */
 	if (pci_is_root_bus(bus))
 		return NULL;
 
-	/* Allocate bitmap */
-	size = ALIGN(phb->ioda.total_pe_num / 8, sizeof(unsigned long));
-	pe_alloc = kzalloc(size, GFP_KERNEL);
+	pe_alloc = bitmap_zalloc(phb->ioda.total_pe_num, GFP_KERNEL);
 	if (!pe_alloc) {
 		pr_warn("%s: Out of memory !\n",
 			__func__);
@@ -319,7 +317,6 @@ static struct pnv_ioda_pe *pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
 	 * pick M64 dependent PE#.
 	 */
 	if (bitmap_empty(pe_alloc, phb->ioda.total_pe_num)) {
-		kfree(pe_alloc);
 		return NULL;
 	}
 
@@ -345,7 +342,6 @@ static struct pnv_ioda_pe *pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all)
 		}
 	}
 
-	kfree(pe_alloc);
 	return master_pe;
 }