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| author |   Matthew Wilcox (Oracle) <willy@infradead.org> | 2021-08-27 07:21:49 -0400 |
|---|---|---|
| committer | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-01-08 00:28:41 -0500 |
| commit | 25a8de7f8d970ffa7263bd9d32a08138cd949f17 (patch) | |
| tree | dad9405842972e385e08f4ae5bfca9778c684934 | |
| parent | truncate,shmem: Handle truncates that split large folios (diff) | |
| download | linux-dev-25a8de7f8d970ffa7263bd9d32a08138cd949f17.tar.xz linux-dev-25a8de7f8d970ffa7263bd9d32a08138cd949f17.zip | |
XArray: Add xas_advance()
Add a new helper function to help iterate over multi-index entries.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
| -rw-r--r-- | include/linux/xarray.h | 18 | ||||
| -rw-r--r-- | lib/xarray.c | 6 |
2 files changed, 21 insertions, 3 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h index a91e3d90df8a..d6d5da6ed735 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -1581,6 +1581,24 @@ static inline void xas_set(struct xa_state *xas, unsigned long index) } /** + * 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. * @index: Target of the operation. diff --git a/lib/xarray.c b/lib/xarray.c index f5d8f54907b4..6f47f6375808 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -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) |