This patch is partially taken from John Grove's famfs dax series. Save the kva for memremap because we need direct_access() support.
Signed-off-by: Dave Jiang <[email protected]> --- drivers/dax/dax-private.h | 4 ++++ drivers/dax/device.c | 19 +++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index c6ae27c982f4..425a515905e5 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -69,6 +69,8 @@ struct dev_dax_range { * data while the device is activated in the driver. * @region: parent region * @dax_dev: core dax functionality + * @virt_addr: kva from memremap; used by fsdev_dax + * @cached_size: cached size of the memory range for quick access; used by fsdev_dax * @align: alignment of this instance * @target_node: effective numa node if dev_dax memory range is onlined * @dyn_id: is this a dynamic or statically created instance @@ -83,6 +85,8 @@ struct dev_dax_range { struct dev_dax { struct dax_region *region; struct dax_device *dax_dev; + void *virt_addr; + u64 cached_size; unsigned int align; int target_node; bool dyn_id; diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 62206bcb63a6..4ffa3ef60a57 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -370,6 +370,7 @@ static int dax_open(struct inode *inode, struct file *filp) filp->f_sb_err = file_sample_sb_err(filp); filp->private_data = dev_dax; inode->i_flags = S_DAX; + inode->i_size = dev_dax->cached_size; return 0; } @@ -408,7 +409,9 @@ static int dev_dax_probe(struct dev_dax *dev_dax) struct device *dev = &dev_dax->dev; struct dev_pagemap *pgmap; struct inode *inode; + u64 data_offset = 0; struct cdev *cdev; + u64 len = 0; void *addr; int rc, i; @@ -451,6 +454,7 @@ static int dev_dax_probe(struct dev_dax *dev_dax) i, range->start, range->end); return -EBUSY; } + len += range_len(range); } pgmap->type = MEMORY_DEVICE_GENERIC; @@ -461,6 +465,21 @@ 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 = dev_dax->ranges[0].range.start; + u64 pgmap_phys = dev_dax->pgmap[0].range.start; + + if (!WARN_ON(pgmap_phys > phys)) + data_offset = phys - pgmap_phys; + + pr_debug("%s: offset detected phys=%llx pgmap_phys=%llx offset=%llx\n", + __func__, phys, pgmap_phys, data_offset); + } + + dev_dax->virt_addr = addr + data_offset; + dev_dax->cached_size = len; + inode = dax_inode(dax_dev); cdev = inode->i_cdev; cdev_init(cdev, &dax_fops); -- 2.53.0
