Setup a dax_dev to have the same lifetime as the dcssblk block device
and add a ->direct_access() method that is equivalent to
dcssblk_direct_access(). Once fs/dax.c has been converted to use
dax_operations the old dcssblk_direct_access() will be removed.
Reported-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
Changes since v2:
* fix return code in the alloc_dax() failure case (Gerald)
* assign dax_dev to dev_info and kill local variable (Gerald)
drivers/s390/block/Kconfig | 1 +
drivers/s390/block/dcssblk.c | 55 +++++++++++++++++++++++++++++++++++-------
2 files changed, 47 insertions(+), 9 deletions(-)
diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
index 4a3b62326183..0acb8c2f9475 100644
--- a/drivers/s390/block/Kconfig
+++ b/drivers/s390/block/Kconfig
@@ -14,6 +14,7 @@ config BLK_DEV_XPRAM
config DCSSBLK
def_tristate m
+ select DAX
prompt "DCSSBLK support"
depends on S390 && BLOCK
help
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 415d10a67b7a..dc84cfd4e438 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/pfn_t.h>
+#include <linux/dax.h>
#include <asm/extmem.h>
#include <asm/io.h>
@@ -30,8 +31,10 @@ static int dcssblk_open(struct block_device *bdev, fmode_t mode);
static void dcssblk_release(struct gendisk *disk, fmode_t mode);
static blk_qc_t dcssblk_make_request(struct request_queue *q,
struct bio *bio);
-static long dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
+static long dcssblk_blk_direct_access(struct block_device *bdev, sector_t secnum,
void **kaddr, pfn_t *pfn, long size);
+static long dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn);
static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
@@ -40,7 +43,11 @@ static const struct block_device_operations dcssblk_devops = {
.owner = THIS_MODULE,
.open = dcssblk_open,
.release = dcssblk_release,
- .direct_access = dcssblk_direct_access,
+ .direct_access = dcssblk_blk_direct_access,
+};
+
+static const struct dax_operations dcssblk_dax_ops = {
+ .direct_access = dcssblk_dax_direct_access,
};
struct dcssblk_dev_info {
@@ -57,6 +64,7 @@ struct dcssblk_dev_info {
struct request_queue *dcssblk_queue;
int num_of_segments;
struct list_head seg_list;
+ struct dax_device *dax_dev;
};
struct segment_info {
@@ -389,6 +397,8 @@ dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const ch
}
list_del(&dev_info->lh);
+ kill_dax(dev_info->dax_dev);
+ put_dax(dev_info->dax_dev);
del_gendisk(dev_info->gd);
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
@@ -654,6 +664,13 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
if (rc)
goto put_dev;
+ dev_info->dax_dev = alloc_dax(dev_info, dev_info->gd->disk_name,
+ &dcssblk_dax_ops);
+ if (!dev_info->dax_dev) {
+ rc = -ENOMEM;
+ goto put_dev;
+ }
+
get_device(&dev_info->dev);
device_add_disk(&dev_info->dev, dev_info->gd);
@@ -752,6 +769,8 @@ dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const ch
}
list_del(&dev_info->lh);
+ kill_dax(dev_info->dax_dev);
+ put_dax(dev_info->dax_dev);
del_gendisk(dev_info->gd);
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
@@ -883,21 +902,39 @@ dcssblk_make_request(struct request_queue *q, struct bio *bio)
}
static long
-dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
+__dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn)
+{
+ resource_size_t offset = pgoff * PAGE_SIZE;
+ unsigned long dev_sz;
+
+ dev_sz = dev_info->end - dev_info->start + 1;
+ *kaddr = (void *) dev_info->start + offset;
+ *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), PFN_DEV);
+
+ return (dev_sz - offset) / PAGE_SIZE;
+}
+
+static long
+dcssblk_blk_direct_access(struct block_device *bdev, sector_t secnum,
void **kaddr, pfn_t *pfn, long size)
{
struct dcssblk_dev_info *dev_info;
- unsigned long offset, dev_sz;
dev_info = bdev->bd_disk->private_data;
if (!dev_info)
return -ENODEV;
- dev_sz = dev_info->end - dev_info->start + 1;
- offset = secnum * 512;
- *kaddr = (void *) dev_info->start + offset;
- *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset), PFN_DEV);
+ return __dcssblk_direct_access(dev_info, PHYS_PFN(secnum * 512),
+ PHYS_PFN(size), kaddr, pfn) * PAGE_SIZE;
+}
+
+static long
+dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
+ long nr_pages, void **kaddr, pfn_t *pfn)
+{
+ struct dcssblk_dev_info *dev_info = dax_get_private(dax_dev);
- return dev_sz - offset;
+ return __dcssblk_direct_access(dev_info, pgoff, nr_pages, kaddr, pfn);
}
static void
