Commit 40999b04 authored by Daniel Henrique Barboza's avatar Daniel Henrique Barboza Committed by Michael Ellerman
Browse files

powerpc/pseries: minor enhancements in dlpar_memory_remove_by_ic() 



We don't need the 'lmbs_available' variable to count the valid LMBs and
to check if we have less than 'lmbs_to_remove'. We must ensure that the
entire LMB range must be removed, so we can error out immediately if any
LMB in the range is marked as reserved.

Add a couple of comments explaining the reasoning behind the differences
we have in this function in contrast to what it is done in its sister
function, dlpar_memory_remove_by_count().

Signed-off-by: default avatarDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210512202809.95363-5-danielhb413@gmail.com
parent 163e7921

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

+19 −9
Original line number Diff line number Diff line
@@ -517,7 +517,6 @@ static int dlpar_memory_remove_by_index(u32 drc_index) 
static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index)

{

	struct drmem_lmb *lmb, *start_lmb, *end_lmb;

	int lmbs_available = 0;

	int rc;



	pr_info("Attempting to hot-remove %u LMB(s) at %x\n",
@@ -530,18 +529,29 @@ static int dlpar_memory_remove_by_ic(u32 lmbs_to_remove, u32 drc_index) 
	if (rc)

		return -EINVAL;



	/* Validate that there are enough LMBs to satisfy the request */

	/*

	 * Validate that all LMBs in range are not reserved. Note that it

	 * is ok if they are !ASSIGNED since our goal here is to remove the

	 * LMB range, regardless of whether some LMBs were already removed

	 * by any other reason.

	 *

	 * This is a contrast to what is done in remove_by_count() where we

	 * check for both RESERVED and !ASSIGNED (via lmb_is_removable()),

	 * because we want to remove a fixed amount of LMBs in that function.

	 */

	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {

		if (lmb->flags & DRCONF_MEM_RESERVED)

			break;



		lmbs_available++;

	}



	if (lmbs_available < lmbs_to_remove)

		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;

		}

	}



	for_each_drmem_lmb_in_range(lmb, start_lmb, end_lmb) {

		/*

		 * dlpar_remove_lmb() will error out if the LMB is already

		 * !ASSIGNED, but this case is a no-op for us.

		 */

		if (!(lmb->flags & DRCONF_MEM_ASSIGNED))

			continue;