From: Boaz Harrosh <boaz@plexistor.com>
To: Dan Williams <dan.j.williams@intel.com>, linux-kernel@vger.kernel.org
Cc: axboe@kernel.dk, riel@redhat.com, linux-nvdimm@lists.01.org,
linux-mm@kvack.org, mgorman@suse.de,
torvalds@linux-foundation.org, hch@lst.de
Subject: Re: [PATCH v5 4/5] dax: fix mapping lifetime handling, convert to __pfn_t + kmap_atomic_pfn_t()
Date: Thu, 13 Aug 2015 09:26:56 +0300 [thread overview]
Message-ID: <55CC38B0.70502@plexistor.com> (raw)
In-Reply-To: <20150813030119.36703.48416.stgit@otcpl-skl-sds-2.jf.intel.com>
On 08/13/2015 06:01 AM, Dan Williams wrote:
> 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_DEV_PFN=n) or be prepared to handle non-page
> backed case (CONFIG_DEV_PFN=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.
>
> This also simplifies the calling convention of ->direct_access() by not
> returning the virtual address in the same call. This annotates cases
> where the kernel is directly accessing pmem outside the driver, and
> makes the valid lifetime of the reference explicit. This property may
> be useful in the future for invalidating mappings to pmem, but for now
> it provides some protection against the "pmem disable vs still-in-use"
> race.
>
> Note that axon_ram_direct_access and dcssblk_direct_access were
> previously making potentially incorrect assumptions about the addresses
> they passed to virt_to_phys().
>
> [hch: various minor updates]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
> arch/powerpc/platforms/Kconfig | 1 +
> arch/powerpc/sysdev/axonram.c | 24 ++++++++----
> drivers/block/brd.c | 5 +--
> drivers/nvdimm/Kconfig | 1 +
> drivers/nvdimm/pmem.c | 24 +++++++-----
> drivers/s390/block/Kconfig | 1 +
> drivers/s390/block/dcssblk.c | 23 ++++++++++--
> fs/Kconfig | 1 +
> fs/block_dev.c | 4 +-
> fs/dax.c | 79 +++++++++++++++++++++++++++++-----------
> include/linux/blkdev.h | 7 ++--
> include/linux/mm.h | 12 ++++++
> 12 files changed, 129 insertions(+), 53 deletions(-)
>
> diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
> index b7f9c408bf24..6b1c2f2e5fb4 100644
> --- a/arch/powerpc/platforms/Kconfig
> +++ b/arch/powerpc/platforms/Kconfig
> @@ -307,6 +307,7 @@ config CPM2
> config AXON_RAM
> tristate "Axon DDR2 memory device driver"
> depends on PPC_IBM_CELL_BLADE && BLOCK
> + select KMAP_PFN
> default m
> help
> It registers one block device per Axon's DDR2 memory bank found
> diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
> index e8657d3bc588..7c5a1563c0fd 100644
> --- a/arch/powerpc/sysdev/axonram.c
> +++ b/arch/powerpc/sysdev/axonram.c
> @@ -43,6 +43,7 @@
> #include <linux/types.h>
> #include <linux/of_device.h>
> #include <linux/of_platform.h>
> +#include <linux/kmap_pfn.h>
>
> #include <asm/page.h>
> #include <asm/prom.h>
> @@ -141,14 +142,12 @@ 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)
> + __pfn_t *pfn)
> {
> 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(bank->ph_addr + offset, PFN_DEV);
> return bank->size - offset;
> }
>
> @@ -165,9 +164,13 @@ static int axon_ram_probe(struct platform_device *device)
> {
> static int axon_ram_bank_id = -1;
> struct axon_ram_bank *bank;
> - struct resource resource;
> + struct resource *resource;
> int rc = 0;
>
> + resource = devm_kzalloc(&device->dev, sizeof(*resource), GFP_KERNEL);
> + if (!resource)
> + return -ENOMEM;
> +
> axon_ram_bank_id++;
>
> dev_info(&device->dev, "Found memory controller on %s\n",
> @@ -184,13 +187,13 @@ static int axon_ram_probe(struct platform_device *device)
>
> bank->device = device;
>
> - if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
> + if (of_address_to_resource(device->dev.of_node, 0, resource) != 0) {
> dev_err(&device->dev, "Cannot access device tree\n");
> rc = -EFAULT;
> goto failed;
> }
>
> - bank->size = resource_size(&resource);
> + bank->size = resource_size(resource);
>
> if (bank->size == 0) {
> dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
> @@ -202,7 +205,7 @@ static int axon_ram_probe(struct platform_device *device)
> dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
> AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
>
> - bank->ph_addr = resource.start;
> + bank->ph_addr = resource->start;
> bank->io_addr = (unsigned long) ioremap_prot(
> bank->ph_addr, bank->size, _PAGE_NO_CACHE);
> if (bank->io_addr == 0) {
> @@ -211,6 +214,11 @@ static int axon_ram_probe(struct platform_device *device)
> goto failed;
> }
>
> + rc = devm_register_kmap_pfn_range(&device->dev, resource,
> + (void *) bank->io_addr);
> + if (rc)
> + goto failed;
> +
> bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
> if (bank->disk == NULL) {
> dev_err(&device->dev, "Cannot register disk\n");
> diff --git a/drivers/block/brd.c b/drivers/block/brd.c
> index 41528857c70d..6c4b21a4e915 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)
> + __pfn_t *pfn)
> {
> struct brd_device *brd = bdev->bd_disk->private_data;
> struct page *page;
> @@ -381,8 +381,7 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
> page = brd_insert_page(brd, sector);
> if (!page)
> return -ENOSPC;
> - *kaddr = page_address(page);
> - *pfn = page_to_pfn(page);
> + *pfn = page_to_pfn_t(page);
>
> return PAGE_SIZE;
> }
> diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
> index 72226acb5c0f..0d8c6bda7a41 100644
> --- a/drivers/nvdimm/Kconfig
> +++ b/drivers/nvdimm/Kconfig
> @@ -20,6 +20,7 @@ config BLK_DEV_PMEM
> tristate "PMEM: Persistent memory block device support"
> default LIBNVDIMM
> depends on HAS_IOMEM
> + select KMAP_PFN
> select ND_BTT if BTT
> help
> Memory ranges for PMEM are described by either an NFIT
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 5e019a6942ce..85d4101bb821 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -25,6 +25,8 @@
> #include <linux/slab.h>
> #include <linux/pmem.h>
> #include <linux/nd.h>
> +#include <linux/mm.h>
> +#include <linux/kmap_pfn.h>
> #include "nd.h"
>
> struct pmem_device {
> @@ -92,18 +94,12 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
> }
>
> static long pmem_direct_access(struct block_device *bdev, sector_t sector,
> - void **kaddr, unsigned long *pfn)
> + __pfn_t *pfn)
> {
> struct pmem_device *pmem = bdev->bd_disk->private_data;
> size_t offset = sector << 9;
>
> - if (!pmem)
> - return -ENODEV;
> -
> - /* FIXME convert DAX to comprehend that this mapping has a lifetime */
> - *kaddr = (void __force *) pmem->virt_addr + offset;
> - *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
> -
> + *pfn = phys_to_pfn_t(pmem->phys_addr + offset, PFN_DEV);
> return pmem->size - offset;
> }
>
> @@ -149,10 +145,17 @@ static void pmem_detach_disk(struct pmem_device *pmem)
> blk_cleanup_queue(pmem->pmem_queue);
> }
>
> -static int pmem_attach_disk(struct nd_namespace_common *ndns,
> +static int pmem_attach_disk(struct device *dev,
> + struct nd_namespace_common *ndns,
> struct pmem_device *pmem)
> {
> struct gendisk *disk;
> + struct resource *res = &(to_nd_namespace_io(&ndns->dev)->res);
> + int err;
> +
> + err = devm_register_kmap_pfn_range(dev, res, pmem->virt_addr);
> + if (err)
> + return err;
>
> pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
> if (!pmem->pmem_queue)
> @@ -232,7 +235,8 @@ static int nd_pmem_probe(struct device *dev)
> if (nd_btt_probe(ndns, pmem) == 0)
> /* we'll come back as btt-pmem */
> return -ENXIO;
> - return pmem_attach_disk(ndns, pmem);
> +
> + return pmem_attach_disk(dev, ndns, pmem);
> }
>
> static int nd_pmem_remove(struct device *dev)
> diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
> index 4a3b62326183..06c7a1c90d88 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 KMAP_PFN
> prompt "DCSSBLK support"
> depends on S390 && BLOCK
> help
> diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
> index 2f1734ba0e22..42f1546d7b03 100644
> --- a/drivers/s390/block/dcssblk.c
> +++ b/drivers/s390/block/dcssblk.c
> @@ -16,6 +16,7 @@
> #include <linux/blkdev.h>
> #include <linux/completion.h>
> #include <linux/interrupt.h>
> +#include <linux/kmap_pfn.h>
> #include <linux/platform_device.h>
> #include <asm/extmem.h>
> #include <asm/io.h>
> @@ -29,7 +30,7 @@ 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);
> + __pfn_t *pfn);
>
> static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
>
> @@ -520,12 +521,18 @@ static const struct attribute_group *dcssblk_dev_attr_groups[] = {
> static ssize_t
> dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
> {
> + struct resource *res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
> int rc, i, j, num_of_segments;
> struct dcssblk_dev_info *dev_info;
> struct segment_info *seg_info, *temp;
> char *local_buf;
> unsigned long seg_byte_size;
>
> + if (!res) {
> + rc = -ENOMEM;
> + goto out_nobuf;
> + }
> +
> dev_info = NULL;
> seg_info = NULL;
> if (dev != dcssblk_root_dev) {
> @@ -652,6 +659,13 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
> if (rc)
> goto put_dev;
>
> + res->start = dev_info->start;
> + res->end = dev_info->end - 1;
> + rc = devm_register_kmap_pfn_range(&dev_info->dev, res,
> + (void *) dev_info->start);
> + if (rc)
> + goto put_dev;
> +
> get_device(&dev_info->dev);
> add_disk(dev_info->gd);
>
> @@ -699,6 +713,8 @@ seg_list_del:
> out:
> kfree(local_buf);
> out_nobuf:
> + if (res)
> + devm_kfree(dev, res);
> return rc;
> }
>
> @@ -879,7 +895,7 @@ fail:
>
> static long
> dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
> - void **kaddr, unsigned long *pfn)
> + __pfn_t *pfn)
> {
> struct dcssblk_dev_info *dev_info;
> unsigned long offset, dev_sz;
> @@ -889,8 +905,7 @@ dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
> return -ENODEV;
> 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(dev_info->start + offset, PFN_DEV);
>
> return dev_sz - offset;
> }
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 011f43365d7b..bd37234e71a8 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -38,6 +38,7 @@ config FS_DAX
> bool "Direct Access (DAX) support"
> depends on MMU
> depends on !(ARM || MIPS || SPARC)
> + depends on KMAP_PFN
> help
> Direct Access (DAX) can be used on memory-backed block devices.
> If the block device supports DAX and the filesystem supports DAX,
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 3a8ac7edfbf4..73fbc57b6e6d 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -441,7 +441,7 @@ 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)
> + __pfn_t *pfn, long size)
> {
> long avail;
> const struct block_device_operations *ops = bdev->bd_disk->fops;
> @@ -462,7 +462,7 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector,
> sector += get_start_sect(bdev);
> if (sector % (PAGE_SIZE / 512))
> return -EINVAL;
> - avail = ops->direct_access(bdev, sector, addr, pfn);
> + avail = ops->direct_access(bdev, sector, pfn);
> if (!avail)
> return -ERANGE;
> return min(avail, size);
> diff --git a/fs/dax.c b/fs/dax.c
> index c3e21ccfc358..94611f480091 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -26,6 +26,7 @@
> #include <linux/sched.h>
> #include <linux/uio.h>
> #include <linux/vmstat.h>
> +#include <linux/kmap_pfn.h>
>
> int dax_clear_blocks(struct inode *inode, sector_t block, long size)
> {
> @@ -35,13 +36,16 @@ 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);
> + count = bdev_direct_access(bdev, sector, &pfn, size);
> if (count < 0)
> return count;
> BUG_ON(size < count);
> + addr = kmap_atomic_pfn_t(pfn);
> + if (!addr)
> + return -EIO;
> while (count > 0) {
> unsigned pgsz = PAGE_SIZE - offset_in_page(addr);
> if (pgsz > count)
> @@ -57,17 +61,39 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long size)
> sector += pgsz / 512;
> cond_resched();
> }
> + kunmap_atomic_pfn_t(addr);
> } while (size);
>
> return 0;
> }
> EXPORT_SYMBOL_GPL(dax_clear_blocks);
>
> -static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
> +static void *__dax_map_bh(struct buffer_head *bh, unsigned blkbits, __pfn_t *pfn)
> {
> - unsigned long pfn;
> sector_t sector = bh->b_blocknr << (blkbits - 9);
> - return bdev_direct_access(bh->b_bdev, sector, addr, &pfn, bh->b_size);
> + void *addr;
> + long rc;
> +
> + rc = bdev_direct_access(bh->b_bdev, sector, pfn, bh->b_size);
> + if (rc)
> + return ERR_PTR(rc);
> + addr = kmap_atomic_pfn_t(*pfn);
> + if (!addr)
> + return ERR_PTR(-EIO);
> + return addr;
> +}
> +
> +static void *dax_map_bh(struct buffer_head *bh, unsigned blkbits)
> +{
> + __pfn_t pfn;
> +
> + return __dax_map_bh(bh, blkbits, &pfn);
> +}
> +
> +static void dax_unmap_bh(void *addr)
> +{
> + if (!IS_ERR(addr))
> + kunmap_atomic_pfn_t(addr);
> }
>
> static void dax_new_buf(void *addr, unsigned size, unsigned first, loff_t pos,
> @@ -106,7 +132,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> loff_t pos = start;
> loff_t max = start;
> loff_t bh_max = start;
> - void *addr;
> + void *addr = NULL, *kmap = ERR_PTR(-EIO);
> bool hole = false;
>
> if (iov_iter_rw(iter) != WRITE)
> @@ -142,9 +168,13 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> addr = NULL;
> size = bh->b_size - first;
> } else {
> - retval = dax_get_addr(bh, &addr, blkbits);
> - if (retval < 0)
> + dax_unmap_bh(kmap);
> + kmap = dax_map_bh(bh, blkbits);
> + if (IS_ERR(kmap)) {
> + retval = PTR_ERR(kmap);
> break;
> + }
> + addr = kmap;
> if (buffer_unwritten(bh) || buffer_new(bh))
> dax_new_buf(addr, retval, first, pos,
> end);
> @@ -168,6 +198,8 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> addr += len;
> }
>
> + dax_unmap_bh(kmap);
> +
> return (pos == start) ? retval : pos - start;
> }
>
> @@ -261,11 +293,14 @@ static int copy_user_bh(struct page *to, struct buffer_head *bh,
> unsigned blkbits, unsigned long vaddr)
> {
> void *vfrom, *vto;
> - if (dax_get_addr(bh, &vfrom, blkbits) < 0)
> - return -EIO;
> +
> + vfrom = dax_map_bh(bh, blkbits);
> + if (IS_ERR(vfrom))
> + return PTR_ERR(vfrom);
> vto = kmap_atomic(to);
> copy_user_page(vto, vfrom, vaddr, to);
> kunmap_atomic(vto);
> + dax_unmap_bh(vfrom);
> return 0;
> }
>
> @@ -273,11 +308,10 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
> struct vm_area_struct *vma, struct vm_fault *vmf)
> {
> struct address_space *mapping = inode->i_mapping;
> - sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9);
> unsigned long vaddr = (unsigned long)vmf->virtual_address;
> - void *addr;
> - unsigned long pfn;
> pgoff_t size;
> + __pfn_t pfn;
> + void *addr;
> int error;
>
> i_mmap_lock_read(mapping);
> @@ -295,18 +329,17 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
> goto out;
> }
>
> - error = bdev_direct_access(bh->b_bdev, sector, &addr, &pfn, bh->b_size);
> - if (error < 0)
> - goto out;
> - if (error < PAGE_SIZE) {
> - error = -EIO;
> + addr = __dax_map_bh(bh, inode->i_blkbits, &pfn);
> + if (IS_ERR(addr)) {
> + error = PTR_ERR(addr);
> goto out;
> }
>
> if (buffer_unwritten(bh) || buffer_new(bh))
> clear_page(addr);
> + dax_unmap_bh(addr);
>
Boooo. Here this all set is a joke. The all "pmem disable vs still-in-use" argument is mute
here below you have inserted a live, used for ever, pfn into a process vm without holding
a map.
The all "pmem disable vs still-in-use" is a joke. The FS loaded has a reference on the bdev
and the filehadle has a reference on the FS. So what is exactly this "pmem disable" you are
talking about?
And for god sake. I have a bdev I call bdev_direct_access(sector), the bdev calculated the
exact address for me (base + sector). Now I get back this __pfn_t and I need to call
kmap_atomic_pfn_t() which does a loop to search for my range and again base+offset ?
This all model is broken, sorry?
> - error = vm_insert_mixed(vma, vaddr, pfn);
> + error = vm_insert_mixed(vma, vaddr, __pfn_t_to_pfn(pfn));
>
> out:
> i_mmap_unlock_read(mapping);
> @@ -539,10 +572,12 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
> return err;
> if (buffer_written(&bh)) {
> void *addr;
> - err = dax_get_addr(&bh, &addr, inode->i_blkbits);
> - if (err < 0)
> - return err;
> +
> + addr = dax_map_bh(&bh, inode->i_blkbits);
> + if (IS_ERR(addr))
> + return PTR_ERR(addr);
> memset(addr + offset, 0, length);
> + dax_unmap_bh(addr);
> }
>
> return 0;
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index ff47d5498133..ae59778d8076 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1555,8 +1555,7 @@ struct block_device_operations {
> int (*rw_page)(struct block_device *, sector_t, struct page *, int rw);
> 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 (*direct_access)(struct block_device *, sector_t, __pfn_t *pfn);
> unsigned int (*check_events) (struct gendisk *disk,
> unsigned int clearing);
> /* ->media_changed() is DEPRECATED, use ->check_events() instead */
> @@ -1574,8 +1573,8 @@ extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
> 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);
> +extern long bdev_direct_access(struct block_device *, sector_t,
> + __pfn_t *pfn, long size);
> #else /* CONFIG_BLOCK */
>
> struct block_device;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 57ba5ca6be72..c4683ea2fcab 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -951,6 +951,18 @@ enum {
> #endif
> };
>
> +static inline __pfn_t pfn_to_pfn_t(unsigned long pfn, unsigned long flags)
> +{
> + __pfn_t pfn_t = { .val = (pfn << PAGE_SHIFT) | (flags & PFN_MASK), };
> +
> + return pfn_t;
> +}
> +
> +static inline __pfn_t phys_to_pfn_t(dma_addr_t addr, unsigned long flags)
> +{
> + return pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
> +}
> +
> static inline bool __pfn_t_has_page(__pfn_t pfn)
> {
> return (pfn.val & PFN_DEV) == 0;
>
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@lists.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm
>
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WARNING: multiple messages have this Message-ID (diff)
From: Boaz Harrosh <boaz@plexistor.com>
To: Dan Williams <dan.j.williams@intel.com>, linux-kernel@vger.kernel.org
Cc: axboe@kernel.dk, riel@redhat.com, linux-nvdimm@ml01.01.org,
linux-mm@kvack.org, mgorman@suse.de,
torvalds@linux-foundation.org, hch@lst.de
Subject: Re: [PATCH v5 4/5] dax: fix mapping lifetime handling, convert to __pfn_t + kmap_atomic_pfn_t()
Date: Thu, 13 Aug 2015 09:26:56 +0300 [thread overview]
Message-ID: <55CC38B0.70502@plexistor.com> (raw)
In-Reply-To: <20150813030119.36703.48416.stgit@otcpl-skl-sds-2.jf.intel.com>
On 08/13/2015 06:01 AM, Dan Williams wrote:
> 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_DEV_PFN=n) or be prepared to handle non-page
> backed case (CONFIG_DEV_PFN=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.
>
> This also simplifies the calling convention of ->direct_access() by not
> returning the virtual address in the same call. This annotates cases
> where the kernel is directly accessing pmem outside the driver, and
> makes the valid lifetime of the reference explicit. This property may
> be useful in the future for invalidating mappings to pmem, but for now
> it provides some protection against the "pmem disable vs still-in-use"
> race.
>
> Note that axon_ram_direct_access and dcssblk_direct_access were
> previously making potentially incorrect assumptions about the addresses
> they passed to virt_to_phys().
>
> [hch: various minor updates]
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
> arch/powerpc/platforms/Kconfig | 1 +
> arch/powerpc/sysdev/axonram.c | 24 ++++++++----
> drivers/block/brd.c | 5 +--
> drivers/nvdimm/Kconfig | 1 +
> drivers/nvdimm/pmem.c | 24 +++++++-----
> drivers/s390/block/Kconfig | 1 +
> drivers/s390/block/dcssblk.c | 23 ++++++++++--
> fs/Kconfig | 1 +
> fs/block_dev.c | 4 +-
> fs/dax.c | 79 +++++++++++++++++++++++++++++-----------
> include/linux/blkdev.h | 7 ++--
> include/linux/mm.h | 12 ++++++
> 12 files changed, 129 insertions(+), 53 deletions(-)
>
> diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
> index b7f9c408bf24..6b1c2f2e5fb4 100644
> --- a/arch/powerpc/platforms/Kconfig
> +++ b/arch/powerpc/platforms/Kconfig
> @@ -307,6 +307,7 @@ config CPM2
> config AXON_RAM
> tristate "Axon DDR2 memory device driver"
> depends on PPC_IBM_CELL_BLADE && BLOCK
> + select KMAP_PFN
> default m
> help
> It registers one block device per Axon's DDR2 memory bank found
> diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
> index e8657d3bc588..7c5a1563c0fd 100644
> --- a/arch/powerpc/sysdev/axonram.c
> +++ b/arch/powerpc/sysdev/axonram.c
> @@ -43,6 +43,7 @@
> #include <linux/types.h>
> #include <linux/of_device.h>
> #include <linux/of_platform.h>
> +#include <linux/kmap_pfn.h>
>
> #include <asm/page.h>
> #include <asm/prom.h>
> @@ -141,14 +142,12 @@ 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)
> + __pfn_t *pfn)
> {
> 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(bank->ph_addr + offset, PFN_DEV);
> return bank->size - offset;
> }
>
> @@ -165,9 +164,13 @@ static int axon_ram_probe(struct platform_device *device)
> {
> static int axon_ram_bank_id = -1;
> struct axon_ram_bank *bank;
> - struct resource resource;
> + struct resource *resource;
> int rc = 0;
>
> + resource = devm_kzalloc(&device->dev, sizeof(*resource), GFP_KERNEL);
> + if (!resource)
> + return -ENOMEM;
> +
> axon_ram_bank_id++;
>
> dev_info(&device->dev, "Found memory controller on %s\n",
> @@ -184,13 +187,13 @@ static int axon_ram_probe(struct platform_device *device)
>
> bank->device = device;
>
> - if (of_address_to_resource(device->dev.of_node, 0, &resource) != 0) {
> + if (of_address_to_resource(device->dev.of_node, 0, resource) != 0) {
> dev_err(&device->dev, "Cannot access device tree\n");
> rc = -EFAULT;
> goto failed;
> }
>
> - bank->size = resource_size(&resource);
> + bank->size = resource_size(resource);
>
> if (bank->size == 0) {
> dev_err(&device->dev, "No DDR2 memory found for %s%d\n",
> @@ -202,7 +205,7 @@ static int axon_ram_probe(struct platform_device *device)
> dev_info(&device->dev, "Register DDR2 memory device %s%d with %luMB\n",
> AXON_RAM_DEVICE_NAME, axon_ram_bank_id, bank->size >> 20);
>
> - bank->ph_addr = resource.start;
> + bank->ph_addr = resource->start;
> bank->io_addr = (unsigned long) ioremap_prot(
> bank->ph_addr, bank->size, _PAGE_NO_CACHE);
> if (bank->io_addr == 0) {
> @@ -211,6 +214,11 @@ static int axon_ram_probe(struct platform_device *device)
> goto failed;
> }
>
> + rc = devm_register_kmap_pfn_range(&device->dev, resource,
> + (void *) bank->io_addr);
> + if (rc)
> + goto failed;
> +
> bank->disk = alloc_disk(AXON_RAM_MINORS_PER_DISK);
> if (bank->disk == NULL) {
> dev_err(&device->dev, "Cannot register disk\n");
> diff --git a/drivers/block/brd.c b/drivers/block/brd.c
> index 41528857c70d..6c4b21a4e915 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)
> + __pfn_t *pfn)
> {
> struct brd_device *brd = bdev->bd_disk->private_data;
> struct page *page;
> @@ -381,8 +381,7 @@ static long brd_direct_access(struct block_device *bdev, sector_t sector,
> page = brd_insert_page(brd, sector);
> if (!page)
> return -ENOSPC;
> - *kaddr = page_address(page);
> - *pfn = page_to_pfn(page);
> + *pfn = page_to_pfn_t(page);
>
> return PAGE_SIZE;
> }
> diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig
> index 72226acb5c0f..0d8c6bda7a41 100644
> --- a/drivers/nvdimm/Kconfig
> +++ b/drivers/nvdimm/Kconfig
> @@ -20,6 +20,7 @@ config BLK_DEV_PMEM
> tristate "PMEM: Persistent memory block device support"
> default LIBNVDIMM
> depends on HAS_IOMEM
> + select KMAP_PFN
> select ND_BTT if BTT
> help
> Memory ranges for PMEM are described by either an NFIT
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 5e019a6942ce..85d4101bb821 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -25,6 +25,8 @@
> #include <linux/slab.h>
> #include <linux/pmem.h>
> #include <linux/nd.h>
> +#include <linux/mm.h>
> +#include <linux/kmap_pfn.h>
> #include "nd.h"
>
> struct pmem_device {
> @@ -92,18 +94,12 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector,
> }
>
> static long pmem_direct_access(struct block_device *bdev, sector_t sector,
> - void **kaddr, unsigned long *pfn)
> + __pfn_t *pfn)
> {
> struct pmem_device *pmem = bdev->bd_disk->private_data;
> size_t offset = sector << 9;
>
> - if (!pmem)
> - return -ENODEV;
> -
> - /* FIXME convert DAX to comprehend that this mapping has a lifetime */
> - *kaddr = (void __force *) pmem->virt_addr + offset;
> - *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
> -
> + *pfn = phys_to_pfn_t(pmem->phys_addr + offset, PFN_DEV);
> return pmem->size - offset;
> }
>
> @@ -149,10 +145,17 @@ static void pmem_detach_disk(struct pmem_device *pmem)
> blk_cleanup_queue(pmem->pmem_queue);
> }
>
> -static int pmem_attach_disk(struct nd_namespace_common *ndns,
> +static int pmem_attach_disk(struct device *dev,
> + struct nd_namespace_common *ndns,
> struct pmem_device *pmem)
> {
> struct gendisk *disk;
> + struct resource *res = &(to_nd_namespace_io(&ndns->dev)->res);
> + int err;
> +
> + err = devm_register_kmap_pfn_range(dev, res, pmem->virt_addr);
> + if (err)
> + return err;
>
> pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
> if (!pmem->pmem_queue)
> @@ -232,7 +235,8 @@ static int nd_pmem_probe(struct device *dev)
> if (nd_btt_probe(ndns, pmem) == 0)
> /* we'll come back as btt-pmem */
> return -ENXIO;
> - return pmem_attach_disk(ndns, pmem);
> +
> + return pmem_attach_disk(dev, ndns, pmem);
> }
>
> static int nd_pmem_remove(struct device *dev)
> diff --git a/drivers/s390/block/Kconfig b/drivers/s390/block/Kconfig
> index 4a3b62326183..06c7a1c90d88 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 KMAP_PFN
> prompt "DCSSBLK support"
> depends on S390 && BLOCK
> help
> diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
> index 2f1734ba0e22..42f1546d7b03 100644
> --- a/drivers/s390/block/dcssblk.c
> +++ b/drivers/s390/block/dcssblk.c
> @@ -16,6 +16,7 @@
> #include <linux/blkdev.h>
> #include <linux/completion.h>
> #include <linux/interrupt.h>
> +#include <linux/kmap_pfn.h>
> #include <linux/platform_device.h>
> #include <asm/extmem.h>
> #include <asm/io.h>
> @@ -29,7 +30,7 @@ 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);
> + __pfn_t *pfn);
>
> static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
>
> @@ -520,12 +521,18 @@ static const struct attribute_group *dcssblk_dev_attr_groups[] = {
> static ssize_t
> dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
> {
> + struct resource *res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
> int rc, i, j, num_of_segments;
> struct dcssblk_dev_info *dev_info;
> struct segment_info *seg_info, *temp;
> char *local_buf;
> unsigned long seg_byte_size;
>
> + if (!res) {
> + rc = -ENOMEM;
> + goto out_nobuf;
> + }
> +
> dev_info = NULL;
> seg_info = NULL;
> if (dev != dcssblk_root_dev) {
> @@ -652,6 +659,13 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char
> if (rc)
> goto put_dev;
>
> + res->start = dev_info->start;
> + res->end = dev_info->end - 1;
> + rc = devm_register_kmap_pfn_range(&dev_info->dev, res,
> + (void *) dev_info->start);
> + if (rc)
> + goto put_dev;
> +
> get_device(&dev_info->dev);
> add_disk(dev_info->gd);
>
> @@ -699,6 +713,8 @@ seg_list_del:
> out:
> kfree(local_buf);
> out_nobuf:
> + if (res)
> + devm_kfree(dev, res);
> return rc;
> }
>
> @@ -879,7 +895,7 @@ fail:
>
> static long
> dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
> - void **kaddr, unsigned long *pfn)
> + __pfn_t *pfn)
> {
> struct dcssblk_dev_info *dev_info;
> unsigned long offset, dev_sz;
> @@ -889,8 +905,7 @@ dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
> return -ENODEV;
> 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(dev_info->start + offset, PFN_DEV);
>
> return dev_sz - offset;
> }
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 011f43365d7b..bd37234e71a8 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -38,6 +38,7 @@ config FS_DAX
> bool "Direct Access (DAX) support"
> depends on MMU
> depends on !(ARM || MIPS || SPARC)
> + depends on KMAP_PFN
> help
> Direct Access (DAX) can be used on memory-backed block devices.
> If the block device supports DAX and the filesystem supports DAX,
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index 3a8ac7edfbf4..73fbc57b6e6d 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -441,7 +441,7 @@ 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)
> + __pfn_t *pfn, long size)
> {
> long avail;
> const struct block_device_operations *ops = bdev->bd_disk->fops;
> @@ -462,7 +462,7 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector,
> sector += get_start_sect(bdev);
> if (sector % (PAGE_SIZE / 512))
> return -EINVAL;
> - avail = ops->direct_access(bdev, sector, addr, pfn);
> + avail = ops->direct_access(bdev, sector, pfn);
> if (!avail)
> return -ERANGE;
> return min(avail, size);
> diff --git a/fs/dax.c b/fs/dax.c
> index c3e21ccfc358..94611f480091 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -26,6 +26,7 @@
> #include <linux/sched.h>
> #include <linux/uio.h>
> #include <linux/vmstat.h>
> +#include <linux/kmap_pfn.h>
>
> int dax_clear_blocks(struct inode *inode, sector_t block, long size)
> {
> @@ -35,13 +36,16 @@ 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);
> + count = bdev_direct_access(bdev, sector, &pfn, size);
> if (count < 0)
> return count;
> BUG_ON(size < count);
> + addr = kmap_atomic_pfn_t(pfn);
> + if (!addr)
> + return -EIO;
> while (count > 0) {
> unsigned pgsz = PAGE_SIZE - offset_in_page(addr);
> if (pgsz > count)
> @@ -57,17 +61,39 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long size)
> sector += pgsz / 512;
> cond_resched();
> }
> + kunmap_atomic_pfn_t(addr);
> } while (size);
>
> return 0;
> }
> EXPORT_SYMBOL_GPL(dax_clear_blocks);
>
> -static long dax_get_addr(struct buffer_head *bh, void **addr, unsigned blkbits)
> +static void *__dax_map_bh(struct buffer_head *bh, unsigned blkbits, __pfn_t *pfn)
> {
> - unsigned long pfn;
> sector_t sector = bh->b_blocknr << (blkbits - 9);
> - return bdev_direct_access(bh->b_bdev, sector, addr, &pfn, bh->b_size);
> + void *addr;
> + long rc;
> +
> + rc = bdev_direct_access(bh->b_bdev, sector, pfn, bh->b_size);
> + if (rc)
> + return ERR_PTR(rc);
> + addr = kmap_atomic_pfn_t(*pfn);
> + if (!addr)
> + return ERR_PTR(-EIO);
> + return addr;
> +}
> +
> +static void *dax_map_bh(struct buffer_head *bh, unsigned blkbits)
> +{
> + __pfn_t pfn;
> +
> + return __dax_map_bh(bh, blkbits, &pfn);
> +}
> +
> +static void dax_unmap_bh(void *addr)
> +{
> + if (!IS_ERR(addr))
> + kunmap_atomic_pfn_t(addr);
> }
>
> static void dax_new_buf(void *addr, unsigned size, unsigned first, loff_t pos,
> @@ -106,7 +132,7 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> loff_t pos = start;
> loff_t max = start;
> loff_t bh_max = start;
> - void *addr;
> + void *addr = NULL, *kmap = ERR_PTR(-EIO);
> bool hole = false;
>
> if (iov_iter_rw(iter) != WRITE)
> @@ -142,9 +168,13 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> addr = NULL;
> size = bh->b_size - first;
> } else {
> - retval = dax_get_addr(bh, &addr, blkbits);
> - if (retval < 0)
> + dax_unmap_bh(kmap);
> + kmap = dax_map_bh(bh, blkbits);
> + if (IS_ERR(kmap)) {
> + retval = PTR_ERR(kmap);
> break;
> + }
> + addr = kmap;
> if (buffer_unwritten(bh) || buffer_new(bh))
> dax_new_buf(addr, retval, first, pos,
> end);
> @@ -168,6 +198,8 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
> addr += len;
> }
>
> + dax_unmap_bh(kmap);
> +
> return (pos == start) ? retval : pos - start;
> }
>
> @@ -261,11 +293,14 @@ static int copy_user_bh(struct page *to, struct buffer_head *bh,
> unsigned blkbits, unsigned long vaddr)
> {
> void *vfrom, *vto;
> - if (dax_get_addr(bh, &vfrom, blkbits) < 0)
> - return -EIO;
> +
> + vfrom = dax_map_bh(bh, blkbits);
> + if (IS_ERR(vfrom))
> + return PTR_ERR(vfrom);
> vto = kmap_atomic(to);
> copy_user_page(vto, vfrom, vaddr, to);
> kunmap_atomic(vto);
> + dax_unmap_bh(vfrom);
> return 0;
> }
>
> @@ -273,11 +308,10 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
> struct vm_area_struct *vma, struct vm_fault *vmf)
> {
> struct address_space *mapping = inode->i_mapping;
> - sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9);
> unsigned long vaddr = (unsigned long)vmf->virtual_address;
> - void *addr;
> - unsigned long pfn;
> pgoff_t size;
> + __pfn_t pfn;
> + void *addr;
> int error;
>
> i_mmap_lock_read(mapping);
> @@ -295,18 +329,17 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
> goto out;
> }
>
> - error = bdev_direct_access(bh->b_bdev, sector, &addr, &pfn, bh->b_size);
> - if (error < 0)
> - goto out;
> - if (error < PAGE_SIZE) {
> - error = -EIO;
> + addr = __dax_map_bh(bh, inode->i_blkbits, &pfn);
> + if (IS_ERR(addr)) {
> + error = PTR_ERR(addr);
> goto out;
> }
>
> if (buffer_unwritten(bh) || buffer_new(bh))
> clear_page(addr);
> + dax_unmap_bh(addr);
>
Boooo. Here this all set is a joke. The all "pmem disable vs still-in-use" argument is mute
here below you have inserted a live, used for ever, pfn into a process vm without holding
a map.
The all "pmem disable vs still-in-use" is a joke. The FS loaded has a reference on the bdev
and the filehadle has a reference on the FS. So what is exactly this "pmem disable" you are
talking about?
And for god sake. I have a bdev I call bdev_direct_access(sector), the bdev calculated the
exact address for me (base + sector). Now I get back this __pfn_t and I need to call
kmap_atomic_pfn_t() which does a loop to search for my range and again base+offset ?
This all model is broken, sorry?
> - error = vm_insert_mixed(vma, vaddr, pfn);
> + error = vm_insert_mixed(vma, vaddr, __pfn_t_to_pfn(pfn));
>
> out:
> i_mmap_unlock_read(mapping);
> @@ -539,10 +572,12 @@ int dax_zero_page_range(struct inode *inode, loff_t from, unsigned length,
> return err;
> if (buffer_written(&bh)) {
> void *addr;
> - err = dax_get_addr(&bh, &addr, inode->i_blkbits);
> - if (err < 0)
> - return err;
> +
> + addr = dax_map_bh(&bh, inode->i_blkbits);
> + if (IS_ERR(addr))
> + return PTR_ERR(addr);
> memset(addr + offset, 0, length);
> + dax_unmap_bh(addr);
> }
>
> return 0;
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index ff47d5498133..ae59778d8076 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1555,8 +1555,7 @@ struct block_device_operations {
> int (*rw_page)(struct block_device *, sector_t, struct page *, int rw);
> 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 (*direct_access)(struct block_device *, sector_t, __pfn_t *pfn);
> unsigned int (*check_events) (struct gendisk *disk,
> unsigned int clearing);
> /* ->media_changed() is DEPRECATED, use ->check_events() instead */
> @@ -1574,8 +1573,8 @@ extern int __blkdev_driver_ioctl(struct block_device *, fmode_t, unsigned int,
> 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);
> +extern long bdev_direct_access(struct block_device *, sector_t,
> + __pfn_t *pfn, long size);
> #else /* CONFIG_BLOCK */
>
> struct block_device;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 57ba5ca6be72..c4683ea2fcab 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -951,6 +951,18 @@ enum {
> #endif
> };
>
> +static inline __pfn_t pfn_to_pfn_t(unsigned long pfn, unsigned long flags)
> +{
> + __pfn_t pfn_t = { .val = (pfn << PAGE_SHIFT) | (flags & PFN_MASK), };
> +
> + return pfn_t;
> +}
> +
> +static inline __pfn_t phys_to_pfn_t(dma_addr_t addr, unsigned long flags)
> +{
> + return pfn_to_pfn_t(addr >> PAGE_SHIFT, flags);
> +}
> +
> static inline bool __pfn_t_has_page(__pfn_t pfn)
> {
> return (pfn.val & PFN_DEV) == 0;
>
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@lists.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm
>
next prev parent reply other threads:[~2015-08-13 6:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-13 3:00 [PATCH v5 0/5] introduce __pfn_t for unmapped pfn I/O and DAX lifetime Dan Williams
2015-08-13 3:00 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 1/5] mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h Dan Williams
2015-08-13 3:01 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 2/5] allow mapping page-less memremaped areas into KVA Dan Williams
2015-08-13 3:01 ` Dan Williams
2015-08-13 5:58 ` Boaz Harrosh
2015-08-13 5:58 ` Boaz Harrosh
2015-08-13 12:57 ` Dan Williams
2015-08-13 12:57 ` Dan Williams
2015-08-13 13:23 ` Boaz Harrosh
2015-08-13 13:23 ` Boaz Harrosh
2015-08-13 14:41 ` Christoph Hellwig
2015-08-13 14:41 ` Christoph Hellwig
2015-08-13 15:01 ` Boaz Harrosh
2015-08-13 15:01 ` Boaz Harrosh
2015-08-13 14:37 ` Christoph Hellwig
2015-08-13 14:37 ` Christoph Hellwig
2015-08-13 14:48 ` Boaz Harrosh
2015-08-13 14:48 ` Boaz Harrosh
2015-08-13 15:29 ` Boaz Harrosh
2015-08-13 15:29 ` Boaz Harrosh
2015-08-13 17:37 ` Dave Hansen
2015-08-13 17:37 ` Dave Hansen
2015-08-13 17:35 ` Matthew Wilcox
2015-08-13 17:35 ` Matthew Wilcox
2015-08-13 18:15 ` Dan Williams
2015-08-13 18:15 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 3/5] dax: drop size parameter to ->direct_access() Dan Williams
2015-08-13 3:01 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 4/5] dax: fix mapping lifetime handling, convert to __pfn_t + kmap_atomic_pfn_t() Dan Williams
2015-08-13 3:01 ` Dan Williams
2015-08-13 6:26 ` Boaz Harrosh [this message]
2015-08-13 6:26 ` Boaz Harrosh
2015-08-13 15:21 ` Dan Williams
2015-08-13 15:21 ` Dan Williams
2015-08-13 16:34 ` Boaz Harrosh
2015-08-13 16:34 ` Boaz Harrosh
2015-08-13 18:51 ` Dan Williams
2015-08-13 18:51 ` Dan Williams
2015-08-13 3:01 ` [PATCH v5 5/5] scatterlist: convert to __pfn_t Dan Williams
2015-08-13 3:01 ` Dan Williams
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