[PATCH v5 2/3] cxl/edac: Skip event records marked NOT_REPAIRABLE

[Jongwon Lee <ai@linux.com>]

Bit 1 of the DPA field in General Media and DRAM event records is the
NOT_REPAIRABLE flag. The device sets it when the memory at that DPA
cannot be repaired.

cxl_find_rec_gen_media() and cxl_find_rec_dram() do not check this flag.
A repair request that matches such a record passes the lookup and is
sent to the device. Since the records are keyed by the raw DPA, this
happens today when user space writes the DPA with bit 1 set.

Skip these records in both lookups, so the repair request fails with
-EINVAL. The trace events already show dpa_flags='NOT_REPAIRABLE' for
them, so user space can tell before it asks for a repair.

cxl_find_rec_gen_media() now reads the record, so take the xarray lock
there too, as cxl_find_rec_dram() does. Also make it return bool, since
its only caller just checks the result.

Fixes: 0b5ccb0de1e2 ("cxl/edac: Support for finding memory operation attributes from the current boot")
Signed-off-by: Jongwon Lee <ai@linux.com>
---
 drivers/cxl/core/edac.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
index 4624ab4644..42683b7c54 100644
--- a/drivers/cxl/core/edac.c
+++ b/drivers/cxl/core/edac.c
@@ -918,24 +918,27 @@ struct cxl_mem_repair_attrbs {
 	enum cxl_mem_repair_type repair_type;
 };
 
-static struct cxl_event_gen_media *
-cxl_find_rec_gen_media(struct cxl_memdev *cxlmd,
-		       struct cxl_mem_repair_attrbs *attrbs)
+static inline bool cxl_rec_not_repairable(const struct cxl_event_media_hdr *hdr)
+{
+	return le64_to_cpu(hdr->phys_addr) & CXL_DPA_NOT_REPAIRABLE;
+}
+
+static bool cxl_find_rec_gen_media(struct cxl_memdev *cxlmd,
+				   struct cxl_mem_repair_attrbs *attrbs)
 {
 	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
 	struct cxl_event_gen_media *rec;
+	bool found;
 
-	if (!array_rec)
-		return NULL;
+	if (!array_rec || attrbs->repair_type != CXL_PPR)
+		return false;
 
+	xa_lock(&array_rec->rec_gen_media);
 	rec = xa_load(&array_rec->rec_gen_media, attrbs->dpa);
-	if (!rec)
-		return NULL;
-
-	if (attrbs->repair_type == CXL_PPR)
-		return rec;
+	found = rec && !cxl_rec_not_repairable(&rec->media_hdr);
+	xa_unlock(&array_rec->rec_gen_media);
 
-	return NULL;
+	return found;
 }
 
 /* Caller holds the xarray lock. The record may be freed once it is dropped. */
@@ -949,7 +952,7 @@ __cxl_find_rec_dram(struct xarray *rec_xarray,
 	lockdep_assert_held(&rec_xarray->xa_lock);
 
 	rec = xa_load(rec_xarray, attrbs->dpa);
-	if (!rec)
+	if (!rec || cxl_rec_not_repairable(&rec->media_hdr))
 		return NULL;
 
 	validity_flags = get_unaligned_le16(rec->media_hdr.validity_flags);
-- 
2.55.0