poison_by_decoder() stops at the last committed decoder and records the
handoff in ctx->offset, but cxl_get_poison_unmapped() ignores it and
starts after the highest DPA allocation instead. Allocation exist for
uncommitted decoders too, so their DPA is skipped by both phases and
poison there is never reported. Resume the scan at ctx->offset, and scan
later partitions in full, restoring the pre-rewrite behavior.

Fixes: be5cbd084027 ("cxl: Kill enum cxl_decoder_mode")
Signed-off-by: Richard Cheng <icheng@nvidia.com>
---
Changelog:

v2->v3:
    - No code changes.

v1->v2:
    - New added patch ( sashiko's report )
---
 drivers/cxl/core/region.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 52ba8e9e4288..ba77416055f4 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2910,7 +2910,6 @@ static int cxl_get_poison_unmapped(struct cxl_memdev *cxlmd,
 {
 	struct cxl_dev_state *cxlds = cxlmd->cxlds;
 	const struct resource *res;
-	struct resource *p, *last;
 	u64 offset, length;
 	int rc = 0;
 
@@ -2923,10 +2922,8 @@ static int cxl_get_poison_unmapped(struct cxl_memdev *cxlmd,
 	 */
 	for (int i = ctx->part; i < cxlds->nr_partitions; i++) {
 		res = &cxlds->part[i].res;
-		for (p = res->child, last = NULL; p; p = p->sibling)
-			last = p;
-		if (last)
-			offset = last->end + 1;
+		if (i == ctx->part)
+			offset = ctx->offset;
 		else
 			offset = res->start;
 		length = res->end - offset + 1;
-- 
2.43.0