From: John Groves <[email protected]>
Three fixes for fsdev.c:
1. 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.
2. Clear pgmap->vmemmap_shift for static DAX devices. When rebinding a
static device from device_dax (which may set vmemmap_shift based on
alignment) to fsdev_dax, the stale vmemmap_shift persists on the
shared pgmap. Explicitly zero it before devm_memremap_pages() so the
vmemmap is built for order-0 folios as fsdev requires.
3. Clear dev_dax->pgmap on probe failure for dynamic devices. After the
dynamic path sets dev_dax->pgmap, if a later probe step fails, devres
frees the devm_kzalloc'd pgmap but leaves dev_dax->pgmap dangling.
Subsequent probe attempts would hit the "dynamic-dax with pre-populated
page map" check and fail permanently. Use a goto cleanup to NULL
dev_dax->pgmap on error.
Fixes: d5406bd458b0a ("dax: add fsdev.c driver for fs-dax on character dax")
Signed-off-by: John Groves <[email protected]>
---
drivers/dax/fsdev.c | 50 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 40 insertions(+), 10 deletions(-)
diff --git a/drivers/dax/fsdev.c b/drivers/dax/fsdev.c
index 73e3a8fbf416d..de7e6dee68386 100644
--- a/drivers/dax/fsdev.c
+++ b/drivers/dax/fsdev.c
@@ -133,11 +133,26 @@ 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,
@@ -206,6 +221,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
{
struct dax_device *dax_dev = dev_dax->dax_dev;
struct device *dev = &dev_dax->dev;
+ bool pgmap_allocated = false;
struct dev_pagemap *pgmap;
struct inode *inode;
u64 data_offset = 0;
@@ -220,6 +236,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
}
pgmap = dev_dax->pgmap;
+ pgmap->vmemmap_shift = 0;
} else {
size_t pgmap_size;
@@ -235,6 +252,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
pgmap->nr_range = dev_dax->nr_range;
dev_dax->pgmap = pgmap;
+ pgmap_allocated = true;
for (i = 0; i < dev_dax->nr_range; i++) {
struct range *range = &dev_dax->ranges[i].range;
@@ -250,7 +268,8 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
range_len(range), dev_name(dev))) {
dev_warn(dev, "mapping%d: %#llx-%#llx could not reserve
range\n",
i, range->start, range->end);
- return -EBUSY;
+ rc = -EBUSY;
+ goto err_pgmap;
}
}
@@ -270,8 +289,10 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
pgmap->owner = dev_dax;
addr = devm_memremap_pages(dev, pgmap);
- if (IS_ERR(addr))
- return PTR_ERR(addr);
+ if (IS_ERR(addr)) {
+ rc = PTR_ERR(addr);
+ goto err_pgmap;
+ }
/*
* Clear any stale compound folio state left over from a previous
@@ -283,7 +304,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
rc = devm_add_action_or_reset(dev, fsdev_clear_folio_state_action,
dev_dax);
if (rc)
- return rc;
+ goto err_pgmap;
/* Detect whether the data is at a non-zero offset into the memory */
if (pgmap->range.start != dev_dax->ranges[0].range.start) {
@@ -305,23 +326,32 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax)
cdev_set_parent(cdev, &dev->kobj);
rc = cdev_add(cdev, dev->devt, 1);
if (rc)
- return rc;
+ goto err_pgmap;
rc = devm_add_action_or_reset(dev, fsdev_cdev_del, cdev);
if (rc)
- return rc;
+ goto err_pgmap;
/* Set the dax operations for fs-dax access path */
rc = dax_set_ops(dax_dev, &dev_dax_ops);
if (rc)
- return rc;
+ goto err_pgmap;
rc = devm_add_action_or_reset(dev, fsdev_clear_ops, dev_dax);
if (rc)
- return rc;
+ goto err_pgmap;
run_dax(dax_dev);
- return devm_add_action_or_reset(dev, fsdev_kill, dev_dax);
+ rc = devm_add_action_or_reset(dev, fsdev_kill, dev_dax);
+ if (rc)
+ goto err_pgmap;
+
+ return 0;
+
+err_pgmap:
+ if (pgmap_allocated)
+ dev_dax->pgmap = NULL;
+ return rc;
}
static struct dax_device_driver fsdev_dax_driver = {
--
2.53.0
