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authorDan Williams <dan.j.williams@intel.com>2016-01-15 16:55:59 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 17:56:32 -0800
commitb2e0d1625e193b40cbbd45b799f82d54d34e015c (patch)
tree88cbdfb54fb23f3a8fae2e05c9b7c897e23fc208 /include/linux/blkdev.h
parentfe683adabfe6629c0b6db32bbbc1ce6cacbf2117 (diff)
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 'include/linux/blkdev.h')
-rw-r--r--include/linux/blkdev.h17
1 files changed, 15 insertions, 2 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index c70e3588a48c..88821fa26f19 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1617,6 +1617,20 @@ static inline bool integrity_req_gap_front_merge(struct request *req,
#endif /* CONFIG_BLK_DEV_INTEGRITY */
+/**
+ * struct blk_dax_ctl - control and output parameters for ->direct_access
+ * @sector: (input) offset relative to a block_device
+ * @addr: (output) kernel virtual address for @sector populated by driver
+ * @pfn: (output) page frame number for @addr populated by driver
+ * @size: (input) number of bytes requested
+ */
+struct blk_dax_ctl {
+ sector_t sector;
+ void __pmem *addr;
+ long size;
+ unsigned long pfn;
+};
+
struct block_device_operations {
int (*open) (struct block_device *, fmode_t);
void (*release) (struct gendisk *, fmode_t);
@@ -1643,8 +1657,7 @@ 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 __pmem **addr, unsigned long *pfn, long size);
+extern long bdev_direct_access(struct block_device *, struct blk_dax_ctl *);
#else /* CONFIG_BLOCK */
struct block_device;