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| author | Dan Williams <dan.j.williams@intel.com> | 2016-01-15 16:55:59 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-01-15 17:56:32 -0800 |
| commit | b2e0d1625e193b40cbbd45b799f82d54d34e015c (patch) | |
| tree | 88cbdfb54fb23f3a8fae2e05c9b7c897e23fc208 /fs/block_dev.c | |
| parent | fe683adabfe6629c0b6db32bbbc1ce6cacbf2117 (diff) | |
| download | lwn-b2e0d1625e193b40cbbd45b799f82d54d34e015c.tar.gz lwn-b2e0d1625e193b40cbbd45b799f82d54d34e015c.zip | |
dax: fix lifetime of in-kernel dax mappings with dax_map_atomic()
The DAX implementation needs to protect new calls to ->direct_access()
and usage of its return value against the driver for the underlying
block device being disabled. Use blk_queue_enter()/blk_queue_exit() to
hold off blk_cleanup_queue() from proceeding, or otherwise fail new
mapping requests if the request_queue is being torn down.
This also introduces blk_dax_ctl to simplify the interface from fs/dax.c
through dax_map_atomic() to bdev_direct_access().
[willy@linux.intel.com: fix read() of a hole]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Jan Kara <jack@suse.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/block_dev.c')
| -rw-r--r-- | fs/block_dev.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index ddc6cdd1860b..530145b607c4 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -455,10 +455,7 @@ EXPORT_SYMBOL_GPL(bdev_write_page); /** * bdev_direct_access() - Get the address for directly-accessibly memory * @bdev: The device containing the memory - * @sector: The offset within the device - * @addr: Where to put the address of the memory - * @pfn: The Page Frame Number for the memory - * @size: The number of bytes requested + * @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 @@ -469,10 +466,10 @@ EXPORT_SYMBOL_GPL(bdev_write_page); * Return: negative errno if an error occurs, otherwise the number of bytes * accessible at this address. */ -long bdev_direct_access(struct block_device *bdev, sector_t sector, - void __pmem **addr, unsigned long *pfn, long size) +long bdev_direct_access(struct block_device *bdev, struct blk_dax_ctl *dax) { - long avail; + sector_t sector = dax->sector; + long avail, size = dax->size; const struct block_device_operations *ops = bdev->bd_disk->fops; /* @@ -491,7 +488,7 @@ 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, &dax->addr, &dax->pfn); if (!avail) return -ERANGE; if (avail > 0 && avail & ~PAGE_MASK) |