Commit bd77a34e authored by Yury Norov (NVIDIA)'s avatar Yury Norov (NVIDIA) Committed by Madhavan Srinivasan
Browse files

powerpc: pci-ioda: Optimize pnv_ioda_pick_m64_pe() 



bitmap_empty() in pnv_ioda_pick_m64_pe() is O(N) and useless because
the following find_next_bit() does the same work.

Drop it, and while there replace a while() loop with the dedicated
for_each_set_bit().

Reviewed-by: default avatarAndrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: default avatarYury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250814190936.381346-3-yury.norov@gmail.com
parent f73338d0

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

+6 −13
Original line number Diff line number Diff line
@@ -295,7 +295,7 @@ 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;

	int i;

	unsigned int i;



	/* Root bus shouldn't use M64 */

	if (pci_is_root_bus(bus))
@@ -311,23 +311,16 @@ static struct pnv_ioda_pe *pnv_ioda_pick_m64_pe(struct pci_bus *bus, bool all) 
	/* Figure out reserved PE numbers by the PE */

	pnv_ioda_reserve_m64_pe(bus, pe_alloc, all);



	/*

	 * the current bus might not own M64 window and that's all

	 * contributed by its child buses. For the case, we needn't

	 * pick M64 dependent PE#.

	 */

	if (bitmap_empty(pe_alloc, phb->ioda.total_pe_num)) {

		return NULL;

	}



	/*

	 * Figure out the master PE and put all slave PEs to master

	 * PE's list to form compound PE.

	 *

	 * The current bus might not own M64 window and that's all

	 * contributed by its child buses. For the case, we needn't

	 * pick M64 dependent PE#.

	 */

	master_pe = NULL;

	i = -1;

	while ((i = find_next_bit(pe_alloc, phb->ioda.total_pe_num, i + 1)) <

		phb->ioda.total_pe_num) {

	for_each_set_bit(i, pe_alloc, phb->ioda.total_pe_num) {

		pe = &phb->ioda.pe_array[i];



		phb->ioda.m64_segmap[pe->pe_number] = pe->pe_number;