extern unsigned int count_data_pages(void);
-/**
- * Auxiliary structure used for reading the snapshot image data and
- * metadata from and writing them to the list of page backup entries
- * (PBEs) which is the main data structure of swsusp.
- *
- * Using struct snapshot_handle we can transfer the image, including its
- * metadata, as a continuous sequence of bytes with the help of
- * snapshot_read_next() and snapshot_write_next().
- *
- * The code that writes the image to a storage or transfers it to
- * the user land is required to use snapshot_read_next() for this
- * purpose and it should not make any assumptions regarding the internal
- * structure of the image. Similarly, the code that reads the image from
- * a storage or transfers it from the user land is required to use
- * snapshot_write_next().
- *
- * This may allow us to change the internal structure of the image
- * in the future with considerably less effort.
- */
-
struct snapshot_handle {
- loff_t offset; /* number of the last byte ready for reading
- * or writing in the sequence
- */
- unsigned int cur; /* number of the block of PAGE_SIZE bytes the
- * next operation will refer to (ie. current)
- */
- unsigned int cur_offset; /* offset with respect to the current
- * block (for the next operation)
- */
- unsigned int prev; /* number of the block of PAGE_SIZE bytes that
- * was the current one previously
- */
- struct pbe *pbe; /* PBE that corresponds to 'buffer' */
- struct pbe *last_pbe; /* When the image is restored (eg. read
- * from disk) we can store some image
- * data directly in the page frames
- * in which they were before suspend.
- * In such a case the PBEs that
- * correspond to them will be unused.
- * This is the last PBE, so far, that
- * does not correspond to such data.
- */
- void *buffer; /* address of the block to read from
- * or write to
- */
- unsigned int buf_offset; /* location to read from or write to,
- * given as a displacement from 'buffer'
- */
- int sync_read; /* Set to one to notify the caller of
- * snapshot_write_next() that it may
- * need to call wait_on_bio_chain()
- */
+ loff_t offset;
+ unsigned int page;
+ unsigned int page_offset;
+ unsigned int prev;
+ struct pbe *pbe;
+ void *buffer;
+ unsigned int buf_offset;
};
-/* This macro returns the address from/to which the caller of
- * snapshot_read_next()/snapshot_write_next() is allowed to
- * read/write data after the function returns
- */
#define data_of(handle) ((handle).buffer + (handle).buf_offset)
extern int snapshot_read_next(struct snapshot_handle *handle, size_t count);