Save the kva from memremap because we need it for iomap rw support Prior to famfs, there were no iomap users of /dev/dax - so the virtual address from memremap was not needed. Also: in some cases dev_dax_probe() is called with the first dev_dax->range offset past pgmap[0].range. In those cases we need to add the difference to virt_addr in order to have the physaddr's in dev_dax->ranges match dev_dax->virt_addr. Dragons... Signed-off-by: John Groves <john@xxxxxxxxxx> --- drivers/dax/dax-private.h | 1 + drivers/dax/device.c | 15 +++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index 446617b73aea..894eb1c66b4a 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -63,6 +63,7 @@ struct dax_mapping { struct dev_dax { struct dax_region *region; struct dax_device *dax_dev; + u64 virt_addr; unsigned int align; int target_node; bool dyn_id; diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 40ba660013cf..6cd79d00fe1b 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -372,6 +372,7 @@ static int dev_dax_probe(struct dev_dax *dev_dax) struct dax_device *dax_dev = dev_dax->dax_dev; struct device *dev = &dev_dax->dev; struct dev_pagemap *pgmap; + u64 data_offset = 0; struct inode *inode; struct cdev *cdev; void *addr; @@ -426,6 +427,20 @@ static int dev_dax_probe(struct dev_dax *dev_dax) if (IS_ERR(addr)) return PTR_ERR(addr); + /* 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 = (u64)dev_dax->ranges[0].range.start; + u64 pgmap_phys = (u64)dev_dax->pgmap[0].range.start; + u64 vmemmap_shift = (u64)dev_dax->pgmap[0].vmemmap_shift; + + if (!WARN_ON(pgmap_phys > phys)) + data_offset = phys - pgmap_phys; + + pr_notice("%s: offset detected phys=%llx pgmap_phys=%llx offset=%llx shift=%llx\n", + __func__, phys, pgmap_phys, data_offset, vmemmap_shift); + } + dev_dax->virt_addr = (u64)addr + data_offset; + inode = dax_inode(dax_dev); cdev = inode->i_cdev; cdev_init(cdev, &dax_fops); -- 2.43.0