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authorDan Williams <dan.j.williams@intel.com>2016-01-16 03:55:59 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-16 04:56:32 +0300
commitb2e0d1625e193b40cbbd45b799f82d54d34e015c (patch)
tree88cbdfb54fb23f3a8fae2e05c9b7c897e23fc208 /fs/block_dev.c
parentfe683adabfe6629c0b6db32bbbc1ce6cacbf2117 (diff)
downloadlinux-b2e0d1625e193b40cbbd45b799f82d54d34e015c.tar.xz
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.c13
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)