From: John Groves Fix memory_failure offset calculation for multi-range devices. The old code subtracted ranges[0].range.start from the faulting PFN's physical address, which produces an incorrect (inflated) logical offset when the PFN falls in ranges[1] or beyond due to physical gaps between ranges. Add fsdev_pfn_to_offset() to walk the range list and compute the correct device-linear byte offset. Fixes: d5406bd458b0a ("dax: add fsdev.c driver for fs-dax on character dax") Reviewed-by: Dave Jiang Reviewed-by: Alison Schofield Signed-off-by: John Groves --- drivers/dax/fsdev.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/dax/fsdev.c b/drivers/dax/fsdev.c index 188b2526bee45..f315533b299e9 100644 --- a/drivers/dax/fsdev.c +++ b/drivers/dax/fsdev.c @@ -135,11 +135,26 @@ static void fsdev_clear_ops(void *data) * The core mm code in free_zone_device_folio() handles the wake_up_var() * directly for this memory type. */ +static u64 fsdev_pfn_to_offset(struct dev_dax *dev_dax, unsigned long pfn) +{ + phys_addr_t phys = PFN_PHYS(pfn); + u64 offset = 0; + + for (int i = 0; i < dev_dax->nr_range; i++) { + struct range *range = &dev_dax->ranges[i].range; + + if (phys >= range->start && phys <= range->end) + return offset + (phys - range->start); + offset += range_len(range); + } + return -1ULL; +} + static int fsdev_pagemap_memory_failure(struct dev_pagemap *pgmap, unsigned long pfn, unsigned long nr_pages, int mf_flags) { struct dev_dax *dev_dax = pgmap->owner; - u64 offset = PFN_PHYS(pfn) - dev_dax->ranges[0].range.start; + u64 offset = fsdev_pfn_to_offset(dev_dax, pfn); u64 len = nr_pages << PAGE_SHIFT; return dax_holder_notify_failure(dev_dax->dax_dev, offset, -- 2.53.0