The primary source for non-page-backed page-frames to enter the system
is via the pmem driver's ->direct_access() method. The pfns returned by
the top-level bdev_direct_access() may be passed to any other subsystem
in the kernel and those sub-systems either need to assume that the pfn
is page backed (CONFIG_PMEM_IO=n) or be prepared to handle non-page
backed case (CONFIG_PMEM_IO=y). Currently the pfns returned by
->direct_access() are only ever used by vm_insert_mixed() which does not
care if the pfn is mapped. As we go to add more usages of these pfns
add the type-safety of __pfn_t.
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Boaz Harrosh <boaz@xxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
arch/powerpc/sysdev/axonram.c | 4 ++--
drivers/block/brd.c | 4 ++--
drivers/block/pmem.c | 8 +++++---
drivers/s390/block/dcssblk.c | 6 +++---
fs/block_dev.c | 2 +-
fs/dax.c | 9 +++++----
include/asm-generic/pfn.h | 7 +++++++
include/linux/blkdev.h | 4 ++--
8 files changed, 27 insertions(+), 17 deletions(-)
diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index 9bb5da7f2c0c..069cb5285f18 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -141,13 +141,13 @@ axon_ram_make_request(struct request_queue *queue, struct bio *bio)
*/
static long
axon_ram_direct_access(struct block_device *device, sector_t sector,
- void **kaddr, unsigned long *pfn, long size)
+ void **kaddr, __pfn_t *pfn, long size)
{
struct axon_ram_bank *bank = device->bd_disk->private_data;
loff_t offset = (loff_t)sector << AXON_RAM_SECTOR_SHIFT;
*kaddr = (void *)(bank->ph_addr + offset);
- *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
+ *pfn = phys_to_pfn_t(virt_to_phys(*kaddr));
return bank->size - offset;
}
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 115c6cf9cb43..57f4cd787ea2 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -371,7 +371,7 @@ static int brd_rw_page(struct block_device *bdev, sector_t sector,
#ifdef CONFIG_BLK_DEV_RAM_DAX
static long brd_direct_access(struct block_device *bdev, sector_t sector,
- void **kaddr, unsigned long *pfn, long size)
+ void **kaddr, __pfn_t *pfn, long size)
{
struct brd_device *brd = bdev->bd_disk->private_data;
struct page *page;
@@ -382,7 +382,7 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
if (!page)
return -ENOSPC;
*kaddr = page_address(page);
- *pfn = page_to_pfn(page);
+ *pfn = page_to_pfn_t(page);
/*
* TODO: If size > PAGE_SIZE, we could look to see if the next page in
diff --git a/drivers/block/pmem.c b/drivers/block/pmem.c
index 2a847651f8de..18edb48e405e 100644
--- a/drivers/block/pmem.c
+++ b/drivers/block/pmem.c
@@ -98,8 +98,8 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
return 0;
}
-static long pmem_direct_access(struct block_device *bdev, sector_t sector,
- void **kaddr, unsigned long *pfn, long size)
+static long __maybe_unused pmem_direct_access(struct block_device *bdev,
+ sector_t sector, void **kaddr, __pfn_t *pfn, long size)
{
struct pmem_device *pmem = bdev->bd_disk->private_data;
size_t offset = sector << 9;
@@ -108,7 +108,7 @@ static long pmem_direct_access(struct block_device *bdev, sector_t sector,
return -ENODEV;
*kaddr = pmem->virt_addr + offset;
- *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
+ *pfn = phys_to_pfn_t(pmem->phys_addr + offset);
return pmem->size - offset;
}
@@ -116,7 +116,9 @@ static long pmem_direct_access(struct block_device *bdev, sector_t sector,
static const struct block_device_operations pmem_fops = {
.owner = THIS_MODULE,
.rw_page = pmem_rw_page,
+#if IS_ENABLED(CONFIG_PMEM_IO)
.direct_access = pmem_direct_access,
+#endif
};
static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index 5da8515b8fb9..8616c1d33786 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -29,7 +29,7 @@ static int dcssblk_open(struct block_device *bdev, fmode_t mode);
static void dcssblk_release(struct gendisk *disk, fmode_t mode);
static void dcssblk_make_request(struct request_queue *q, struct bio *bio);
static long dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
- void **kaddr, unsigned long *pfn, long size);
+ void **kaddr, __pfn_t *pfn, long size);
static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
@@ -879,7 +879,7 @@ fail:
static long
dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
- void **kaddr, unsigned long *pfn, long size)
+ void **kaddr, __pfn_t *pfn, long size)
{
struct dcssblk_dev_info *dev_info;
unsigned long offset, dev_sz;
@@ -890,7 +890,7 @@ dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
dev_sz = dev_info->end - dev_info->start;
offset = secnum * 512;
*kaddr = (void *) (dev_info->start + offset);
- *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
+ *pfn = phys_to_pfn_t(virt_to_phys(*kaddr));
return dev_sz - offset;
}
diff --git a/fs/block_dev.c b/fs/block_dev.c
index c7e4163ede87..7285c31f7e30 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -437,7 +437,7 @@ EXPORT_SYMBOL_GPL(bdev_write_page);
* accessible at this address.
*/
long bdev_direct_access(struct block_device *bdev, sector_t sector,
- void **addr, unsigned long *pfn, long size)
+ void **addr, __pfn_t *pfn, long size)
{
long avail;
const struct block_device_operations *ops = bdev->bd_disk->fops;
diff --git a/fs/dax.c b/fs/dax.c
index 6f65f00e58ec..198bd0e4b5ae 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -35,7 +35,7 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long size)
might_sleep();
do {
void *addr;
- unsigned long pfn;
+ __pfn_t pfn;
long count;
count = bdev_direct_access(bdev, sector, &addr, &pfn, size);
@@ -65,7 +65,8 @@ EXPORT_SYMBOL_GPL(dax_clear_blocks);
static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
{
- unsigned long pfn;
+ __pfn_t pfn;
+
sector_t sector = bh->b_blocknr << (blkbits - 9);
return bdev_direct_access(bh->b_bdev, sector, addr, &pfn, bh->b_size);
}
@@ -274,7 +275,7 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9);
unsigned long vaddr = (unsigned long)vmf->virtual_address;
void *addr;
- unsigned long pfn;
+ __pfn_t pfn;
pgoff_t size;
int error;
@@ -304,7 +305,7 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
if (buffer_unwritten(bh) || buffer_new(bh))
clear_page(addr);
- error = vm_insert_mixed(vma, vaddr, pfn);
+ error = vm_insert_mixed(vma, vaddr, __pfn_t_to_pfn(pfn));
out:
i_mmap_unlock_read(mapping);
diff --git a/include/asm-generic/pfn.h b/include/asm-generic/pfn.h
index c1fdf41fb726..af219dc96792 100644
--- a/include/asm-generic/pfn.h
+++ b/include/asm-generic/pfn.h
@@ -49,6 +49,13 @@ static inline __pfn_t page_to_pfn_t(struct page *page)
return pfn;
}
+static inline __pfn_t phys_to_pfn_t(phys_addr_t addr)
+{
+ __pfn_t pfn = { .pfn = addr >> PAGE_SHIFT };
+
+ return pfn;
+}
+
static inline unsigned long __pfn_t_to_pfn(__pfn_t pfn)
{
#if IS_ENABLED(CONFIG_PMEM_IO)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7f9a516f24de..2692d3936f5f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1605,7 +1605,7 @@ struct block_device_operations {
int (*ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
int (*compat_ioctl) (struct block_device *, fmode_t, unsigned, unsigned long);
long (*direct_access)(struct block_device *, sector_t,
- void **, unsigned long *pfn, long size);
+ void **, __pfn_t *pfn, long size);
unsigned int (*check_events) (struct gendisk *disk,
unsigned int clearing);
/* ->media_changed() is DEPRECATED, use ->check_events() instead */
@@ -1624,7 +1624,7 @@ extern int bdev_read_page(struct block_device *, sector_t, struct page *);
extern int bdev_write_page(struct block_device *, sector_t, struct page *,
struct writeback_control *);
extern long bdev_direct_access(struct block_device *, sector_t, void **addr,
- unsigned long *pfn, long size);
+ __pfn_t *pfn, long size);
#else /* CONFIG_BLOCK */
struct block_device;
--
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