[PATCH] powerpc/pserie: Use lmb_is_removable() to check removability

[PATCH] powerpc/pserie: Use lmb_is_removable() to check removability

[Nathan Fontenot]

We should be using lmb_is_removable() to validate that enough LMBs
are available to remove when doing a remove by count. This will check
that the LMB is owned by the system and it is considered removable.
This patch also adds a pr_info() notification to report the LMB count
to remove was not satisfied.

What we do now is just check that there are enough LMBs owned by the
system when validating there are enough LMBs to remove. This can
lead to situations where there are enough LMBs owned by the system
but not enough that are considered removable. This results in having
to bail out of the remove operation instead of just failing the request
that we should have known wouldn't succeed.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/pseries/hotplug-memory.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 76ec104..2617f9f 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -472,12 +472,15 @@ static int dlpar_memory_remove_by_count(u32 lmbs_to_remove,
 
 	/* Validate that there are enough LMBs to satisfy the request */
 	for (i = 0; i < num_lmbs; i++) {
-		if (lmbs[i].flags & DRCONF_MEM_ASSIGNED)
+		if (lmb_is_removable(&lmbs[i]))
 			lmbs_available++;
 	}
 
-	if (lmbs_available < lmbs_to_remove)
+	if (lmbs_available < lmbs_to_remove) {
+		pr_info("Not enough LMBs available (%d of %d) to satisfy request\n",
+			lmbs_available, lmbs_to_remove);
 		return -EINVAL;
+	}
 
 	for (i = 0; i < num_lmbs && lmbs_removed < lmbs_to_remove; i++) {
 		rc = dlpar_remove_lmb(&lmbs[i]);

Re: powerpc/pserie: Use lmb_is_removable() to check removability

[Michael Ellerman]

On Mon, 2016-11-28 at 16:50:45 UTC, Nathan Fontenot wrote:
> We should be using lmb_is_removable() to validate that enough LMBs
> are available to remove when doing a remove by count. This will check
> that the LMB is owned by the system and it is considered removable.
> This patch also adds a pr_info() notification to report the LMB count
> to remove was not satisfied.
> 
> What we do now is just check that there are enough LMBs owned by the
> system when validating there are enough LMBs to remove. This can
> lead to situations where there are enough LMBs owned by the system
> but not enough that are considered removable. This results in having
> to bail out of the remove operation instead of just failing the request
> that we should have known wouldn't succeed.
> 
> Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/2db029ef58ab7c47cecab5fe73fa6e

cheers