Commit 25a8de7f authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

XArray: Add xas_advance() 



Add a new helper function to help iterate over multi-index entries.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarWilliam Kucharski <william.kucharski@oracle.com>
parent b9a8a419

include/linux/xarray.h

+18 −0
Original line number Diff line number Diff line
@@ -1580,6 +1580,24 @@ static inline void xas_set(struct xa_state *xas, unsigned long index) 
	xas->xa_node = XAS_RESTART;

}



/**

 * xas_advance() - Skip over sibling entries.

 * @xas: XArray operation state.

 * @index: Index of last sibling entry.

 *

 * Move the operation state to refer to the last sibling entry.

 * This is useful for loops that normally want to see sibling

 * entries but sometimes want to skip them.  Use xas_set() if you

 * want to move to an index which is not part of this entry.

 */

static inline void xas_advance(struct xa_state *xas, unsigned long index)

{

	unsigned char shift = xas_is_node(xas) ? xas->xa_node->shift : 0;



	xas->xa_index = index;

	xas->xa_offset = (index >> shift) & XA_CHUNK_MASK;

}



/**

 * xas_set_order() - Set up XArray operation state for a multislot entry.

 * @xas: XArray operation state.

lib/xarray.c

+3 −3
Original line number Diff line number Diff line
@@ -157,7 +157,7 @@ static void xas_move_index(struct xa_state *xas, unsigned long offset) 
	xas->xa_index += offset << shift;

}



static void xas_advance(struct xa_state *xas)

static void xas_next_offset(struct xa_state *xas)

{

	xas->xa_offset++;

	xas_move_index(xas, xas->xa_offset);
@@ -1250,7 +1250,7 @@ void *xas_find(struct xa_state *xas, unsigned long max) 
		xas->xa_offset = ((xas->xa_index - 1) & XA_CHUNK_MASK) + 1;

	}



	xas_advance(xas);

	xas_next_offset(xas);



	while (xas->xa_node && (xas->xa_index <= max)) {

		if (unlikely(xas->xa_offset == XA_CHUNK_SIZE)) {
@@ -1268,7 +1268,7 @@ void *xas_find(struct xa_state *xas, unsigned long max) 
		if (entry && !xa_is_sibling(entry))

			return entry;



		xas_advance(xas);

		xas_next_offset(xas);

	}



	if (!xas->xa_node)