From: John Groves <[email protected]>
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")
Signed-off-by: John Groves <[email protected]>
---
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
