diff --git a/drivers/dax/fsdev.c b/drivers/dax/fsdev.c index dbd722ed7ab0..0fd5e1293d72 100644 --- a/drivers/dax/fsdev.c +++ b/drivers/dax/fsdev.c @@ -219,6 +219,48 @@ static const struct file_operations fsdev_fops = { .release = fsdev_release, }; +/* + * Acquire the dev_pagemap for probe: the static (pre-populated) one if + * present, or a devm-allocated one for the dynamic case. Note that + * dev_dax->pgmap is not set here; fsdev_dax_probe() sets it only once + * probe succeeds, so a failed probe never leaves a dangling pointer + * to a devres-freed pgmap. + */ +static struct dev_pagemap *fsdev_acquire_pgmap(struct dev_dax *dev_dax) +{ + struct device *dev = &dev_dax->dev; + struct dev_pagemap *pgmap; + size_t pgmap_size; + + if (static_dev_dax(dev_dax)) { + if (dev_dax->nr_range > 1) { + dev_warn(dev, + "static pgmap / multi-range device conflict\n"); + return ERR_PTR(-EINVAL); + } + + pgmap = dev_dax->pgmap; + pgmap->vmemmap_shift = 0; + return pgmap; + } + + if (dev_dax->pgmap) { + dev_warn(dev, "dynamic-dax with pre-populated page map\n"); + return ERR_PTR(-EINVAL); + } + + pgmap_size = struct_size(pgmap, ranges, dev_dax->nr_range - 1); + pgmap = devm_kzalloc(dev, pgmap_size, GFP_KERNEL); + if (!pgmap) + return ERR_PTR(-ENOMEM); + + pgmap->nr_range = dev_dax->nr_range; + for (int i = 0; i < dev_dax->nr_range; i++) + pgmap->ranges[i] = dev_dax->ranges[i].range; + + return pgmap; +} + static int fsdev_dax_probe(struct dev_dax *dev_dax) { struct dax_device *dax_dev = dev_dax->dax_dev; @@ -230,36 +272,9 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax) void *addr; int rc, i; - if (static_dev_dax(dev_dax)) { - if (dev_dax->nr_range > 1) { - dev_warn(dev, "static pgmap / multi-range device conflict\n"); - return -EINVAL; - } - - pgmap = dev_dax->pgmap; - pgmap->vmemmap_shift = 0; - } else { - size_t pgmap_size; - - if (dev_dax->pgmap) { - dev_warn(dev, "dynamic-dax with pre-populated page map\n"); - return -EINVAL; - } - - pgmap_size = struct_size(pgmap, ranges, dev_dax->nr_range - 1); - pgmap = devm_kzalloc(dev, pgmap_size, GFP_KERNEL); - if (!pgmap) - return -ENOMEM; - - pgmap->nr_range = dev_dax->nr_range; - dev_dax->pgmap = pgmap; - - for (i = 0; i < dev_dax->nr_range; i++) { - struct range *range = &dev_dax->ranges[i].range; - - pgmap->ranges[i] = *range; - } - } + pgmap = fsdev_acquire_pgmap(dev_dax); + if (IS_ERR(pgmap)) + return PTR_ERR(pgmap); for (i = 0; i < dev_dax->nr_range; i++) { struct range *range = &dev_dax->ranges[i].range; @@ -306,7 +321,7 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax) /* Detect whether the data is at a non-zero offset into the memory */ if (pgmap->range.start != dev_dax->ranges[0].range.start) { u64 phys = dev_dax->ranges[0].range.start; - u64 pgmap_phys = dev_dax->pgmap[0].range.start; + u64 pgmap_phys = pgmap[0].range.start; if (!WARN_ON(pgmap_phys > phys)) data_offset = phys - pgmap_phys; @@ -339,7 +354,13 @@ static int fsdev_dax_probe(struct dev_dax *dev_dax) return rc; 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) + return rc; + + /* Probe can no longer fail; expose the pgmap via dev_dax */ + dev_dax->pgmap = pgmap; + return 0; } static struct dax_device_driver fsdev_dax_driver = {