From: Li Ming Date: Tue, 3 Jun 2025 10:43:13 +0000 (+0800) Subject: cxl/edac: Fix the min_scrub_cycle of a region miscalculation X-Git-Tag: v6.16-rc4~15^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fdc9be90929081ed5a9658583aa5f3121d5e8365;p=thirdparty%2Flinux.git cxl/edac: Fix the min_scrub_cycle of a region miscalculation When trying to update the scrub_cycle value of a cxl region, which means updating the scrub_cycle value of each memdev under a cxl region. cxl driver needs to guarantee the new scrub_cycle value is greater than the min_scrub_cycle value of a memdev, otherwise the updating operation will fail(Per Table 8-223 in CXL r3.2 section 8.2.10.9.11.1). Current implementation logic of getting the min_scrub_cycle value of a cxl region is that getting the min_scrub_cycle value of each memdevs under the cxl region, then using the minimum min_scrub_cycle value as the region's min_scrub_cycle. Checking if the new scrub_cycle value is greater than this value. If yes, updating the new scrub_cycle value to each memdevs. The issue is that the new scrub_cycle value is possibly greater than the minimum min_scrub_cycle value of all memdevs but less than the maximum min_scrub_cycle value of all memdevs if memdevs have a different min_scrub_cycle value. The updating operation will always fail on these memdevs which have a greater min_scrub_cycle than the new scrub_cycle. The correct implementation logic is to get the maximum value of these memdevs' min_scrub_cycle, check if the new scrub_cycle value is greater than the value. If yes, the new scrub_cycle value is fit for the region. The change also impacts the result of cxl_patrol_scrub_get_min_scrub_cycle(), the interface returned the minimum min_scrub_cycle value among all memdevs under the region before the change. The interface will return the maximum min_scrub_cycle value among all memdevs under the region with the change. Signed-off-by: Li Ming Reviewed-by: Jonathan Cameron Reviewed-by: Dave Jiang Reviewed-by: Shiju Jose Reviewed-by: Davidlohr Bueso Link: https://patch.msgid.link/20250603104314.25569-1-ming.li@zohomail.com Signed-off-by: Dave Jiang --- diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c index 2cbc664e5d626..0ef245d0bd9fd 100644 --- a/drivers/cxl/core/edac.c +++ b/drivers/cxl/core/edac.c @@ -103,10 +103,10 @@ static int cxl_scrub_get_attrbs(struct cxl_patrol_scrub_context *cxl_ps_ctx, u8 *cap, u16 *cycle, u8 *flags, u8 *min_cycle) { struct cxl_mailbox *cxl_mbox; - u8 min_scrub_cycle = U8_MAX; struct cxl_region_params *p; struct cxl_memdev *cxlmd; struct cxl_region *cxlr; + u8 min_scrub_cycle = 0; int i, ret; if (!cxl_ps_ctx->cxlr) { @@ -133,8 +133,12 @@ static int cxl_scrub_get_attrbs(struct cxl_patrol_scrub_context *cxl_ps_ctx, if (ret) return ret; + /* + * The min_scrub_cycle of a region is the max of minimum scrub + * cycles supported by memdevs that back the region. + */ if (min_cycle) - min_scrub_cycle = min(*min_cycle, min_scrub_cycle); + min_scrub_cycle = max(*min_cycle, min_scrub_cycle); } if (min_cycle)