On Wed, May 12, 2021 at 05:28:09PM -0300, Daniel Henrique Barboza wrote: > 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: Daniel Henrique Barboza <danielhb...@gmail.com>
Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
> .../platforms/pseries/hotplug-memory.c | 28 +++++++++++++------
> 1 file changed, 19 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c
> b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index 3c7ce5361ce3..ee88c1540fba 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -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 (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_remove)
> - 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;
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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