From: Daniel Henrique Barboza <danielhb413@gmail•com>
To: linuxppc-dev@lists•ozlabs.org
Cc: Daniel Henrique Barboza <danielhb413@gmail•com>,
david@gibson•dropbear.id.au
Subject: [PATCH v2 4/4] powerpc/pseries: minor enhancements in dlpar_memory_remove_by_ic()
Date: Wed, 12 May 2021 17:28:09 -0300 [thread overview]
Message-ID: <20210512202809.95363-5-danielhb413@gmail.com> (raw)
In-Reply-To: <20210512202809.95363-1-danielhb413@gmail.com>
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 <danielhb413@gmail•com>
---
.../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;
--
2.31.1
next prev parent reply other threads:[~2021-05-12 20:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 20:28 [PATCH v2 0/4] Unisolate LMBs DRC on removal error + cleanups Daniel Henrique Barboza
2021-05-12 20:28 ` [PATCH v2 1/4] powerpc/pseries: Set UNISOLATE on dlpar_memory_remove_by_ic() error Daniel Henrique Barboza
2021-05-12 20:28 ` [PATCH v2 2/4] powerpc/pseries: check DRCONF_MEM_RESERVED in lmb_is_removable() Daniel Henrique Barboza
2021-05-13 5:12 ` David Gibson
2021-05-12 20:28 ` [PATCH v2 3/4] powerpc/pseries: break early in dlpar_memory_remove_by_count() loops Daniel Henrique Barboza
2021-05-13 5:20 ` David Gibson
2021-05-12 20:28 ` Daniel Henrique Barboza [this message]
2021-05-13 5:21 ` [PATCH v2 4/4] powerpc/pseries: minor enhancements in dlpar_memory_remove_by_ic() David Gibson
2021-06-06 12:08 ` [PATCH v2 0/4] Unisolate LMBs DRC on removal error + cleanups Michael Ellerman
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