#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>
{
struct address_space *mapping = bdev->bd_inode->i_mapping;
- if (mapping->nrpages == 0)
- return;
-
- invalidate_bh_lrus();
- lru_add_drain_all(); /* make sure all lru add caches are flushed */
- invalidate_mapping_pages(mapping, 0, -1);
+ if (mapping->nrpages) {
+ invalidate_bh_lrus();
+ lru_add_drain_all(); /* make sure all lru add caches are flushed */
+ invalidate_mapping_pages(mapping, 0, -1);
+ }
/* 99% of the time, we don't need to flush the cleancache on the bdev.
* But, for the strange corners, lets be cautious
*/
}
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)
-{
- sector_t sector = dax->sector;
- long avail, size = dax->size;
- const struct block_device_operations *ops = bdev->bd_disk->fops;
-
- /*
- * 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))
- 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);
-}
-EXPORT_SYMBOL_GPL(bdev_direct_access);
-
-/**
- * bdev_dax_supported() - Check if the device supports dax for filesystem
- * @sb: The superblock of the device
- * @blocksize: The block size of the device
- *
- * This is a library function for filesystems to check if the block device
- * can be mounted with dax option.
- *
- * Return: negative errno if unsupported, 0 if supported.
- */
-int bdev_dax_supported(struct super_block *sb, int blocksize)
-{
- struct blk_dax_ctl dax = {
- .sector = 0,
- .size = PAGE_SIZE,
- };
- int err;
-
- 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);
- }
- 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,
- };
-
- if (!IS_ENABLED(CONFIG_FS_DAX))
- return false;
-
- dax.sector = 0;
- if (bdev_direct_access(bdev, &dax) < 0)
- return false;
-
- dax.sector = bdev->bd_part->nr_sects - (PAGE_SIZE / 512);
- if (bdev_direct_access(bdev, &dax) < 0)
- return false;
-
- return true;
-}
-
/*
* pseudo-fs
*/