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-rw-r--r--fs/block_dev.c117
1 files changed, 35 insertions, 82 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0d435c794d76..2a305c1a2d88 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/blkpg.h>
#include <linux/magic.h>
+#include <linux/dax.h>
#include <linux/buffer_head.h>
#include <linux/swap.h>
#include <linux/pagevec.h>
@@ -716,50 +717,18 @@ int bdev_write_page(struct block_device *bdev, sector_t sector,
}
EXPORT_SYMBOL_GPL(bdev_write_page);
-/**
- * bdev_direct_access() - Get the address for directly-accessibly memory
- * @bdev: The device containing the memory
- * @dax: control and output parameters for ->direct_access
- *
- * If a block device is made up of directly addressable memory, this function
- * will tell the caller the PFN and the address of the memory. The address
- * may be directly dereferenced within the kernel without the need to call
- * ioremap(), kmap() or similar. The PFN is suitable for inserting into
- * page tables.
- *
- * Return: negative errno if an error occurs, otherwise the number of bytes
- * accessible at this address.
- */
-long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax)
+int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
+ pgoff_t *pgoff)
{
- sector_t sector = dax->sector;
- long avail, size = dax->size;
- const struct block_device_operations *ops = bdev->bd_disk->fops;
+ phys_addr_t phys_off = (get_start_sect(bdev) + sector) * 512;
- /*
- * The device driver is allowed to sleep, in order to make the
- * memory directly accessible.
- */
- might_sleep();
-
- if (size < 0)
- return size;
- if (!blk_queue_dax(bdev_get_queue(bdev)) || !ops->direct_access)
- return -EOPNOTSUPP;
- if ((sector + DIV_ROUND_UP(size, 512)) >
- part_nr_sects_read(bdev->bd_part))
- return -ERANGE;
- sector += get_start_sect(bdev);
- if (sector % (PAGE_SIZE / 512))
+ if (pgoff)
+ *pgoff = PHYS_PFN(phys_off);
+ if (phys_off % PAGE_SIZE || size % PAGE_SIZE)
return -EINVAL;
- avail = ops->direct_access(bdev, sector, &dax->addr, &dax->pfn, size);
- if (!avail)
- return -ERANGE;
- if (avail > 0 && avail & ~PAGE_MASK)
- return -ENXIO;
- return min(avail, size);
+ return 0;
}
-EXPORT_SYMBOL_GPL(bdev_direct_access);
+EXPORT_SYMBOL(bdev_dax_pgoff);
/**
* bdev_dax_supported() - Check if the device supports dax for filesystem
@@ -773,62 +742,46 @@ EXPORT_SYMBOL_GPL(bdev_direct_access);
*/
int bdev_dax_supported(struct super_block *sb, int blocksize)
{
- struct blk_dax_ctl dax = {
- .sector = 0,
- .size = PAGE_SIZE,
- };
- int err;
+ struct block_device *bdev = sb->s_bdev;
+ struct dax_device *dax_dev;
+ pgoff_t pgoff;
+ int err, id;
+ void *kaddr;
+ pfn_t pfn;
+ long len;
if (blocksize != PAGE_SIZE) {
vfs_msg(sb, KERN_ERR, "error: unsupported blocksize for dax");
return -EINVAL;
}
- err = bdev_direct_access(sb->s_bdev, &dax);
- if (err < 0) {
- switch (err) {
- case -EOPNOTSUPP:
- vfs_msg(sb, KERN_ERR,
- "error: device does not support dax");
- break;
- case -EINVAL:
- vfs_msg(sb, KERN_ERR,
- "error: unaligned partition for dax");
- break;
- default:
- vfs_msg(sb, KERN_ERR,
- "error: dax access failed (%d)", err);
- }
+ err = bdev_dax_pgoff(bdev, 0, PAGE_SIZE, &pgoff);
+ if (err) {
+ vfs_msg(sb, KERN_ERR, "error: unaligned partition for dax");
return err;
}
- return 0;
-}
-EXPORT_SYMBOL_GPL(bdev_dax_supported);
-
-/**
- * bdev_dax_capable() - Return if the raw device is capable for dax
- * @bdev: The device for raw block device access
- */
-bool bdev_dax_capable(struct block_device *bdev)
-{
- struct blk_dax_ctl dax = {
- .size = PAGE_SIZE,
- };
+ dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
+ if (!dax_dev) {
+ vfs_msg(sb, KERN_ERR, "error: device does not support dax");
+ return -EOPNOTSUPP;
+ }
- if (!IS_ENABLED(CONFIG_FS_DAX))
- return false;
+ id = dax_read_lock();
+ len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
+ dax_read_unlock(id);
- dax.sector = 0;
- if (bdev_direct_access(bdev, &dax) < 0)
- return false;
+ put_dax(dax_dev);
- dax.sector = bdev->bd_part->nr_sects - (PAGE_SIZE / 512);
- if (bdev_direct_access(bdev, &dax) < 0)
- return false;
+ if (len < 1) {
+ vfs_msg(sb, KERN_ERR,
+ "error: dax access failed (%ld)", len);
+ return len < 0 ? len : -EIO;
+ }
- return true;
+ return 0;
}
+EXPORT_SYMBOL_GPL(bdev_dax_supported);
/*
* pseudo-fs