XArray: Add xa_for_each_range (00ed452c) · Commits · 戴 / test

Documentation/core-api/xarray.rst

+6 −4

Original line number	Diff line number	Diff line
		@@ -82,10 +82,10 @@ at that index is ``NULL``, you can use xa_insert() which
		returns ``-EBUSY`` if the entry is not empty.

		You can copy entries out of the XArray into a plain array by calling
		xa_extract(). Or you can iterate over the present entries in
		the XArray by calling xa_for_each(). You may prefer to use
		xa_find() or xa_find_after() to move to the next present
		entry in the XArray.
		xa_extract(). Or you can iterate over the present entries in the XArray
		by calling xa_for_each(), xa_for_each_start() or xa_for_each_range().
		You may prefer to use xa_find() or xa_find_after() to move to the next
		present entry in the XArray.

		Calling xa_store_range() stores the same entry in a range
		of indices. If you do this, some of the other operations will behave
		@@ -193,6 +193,8 @@ No lock needed:
		Takes RCU read lock:
		* xa_load()
		* xa_for_each()
		* xa_for_each_start()
		* xa_for_each_range()
		* xa_find()
		* xa_find_after()
		* xa_extract()

include/linux/xarray.h

+32 −5

Original line number	Diff line number	Diff line
		@@ -416,6 +416,36 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark)
		return xa->xa_flags & XA_FLAGS_MARK(mark);
		}

		/**
		* xa_for_each_range() - Iterate over a portion of an XArray.
		* @xa: XArray.
		* @index: Index of @entry.
		* @entry: Entry retrieved from array.
		* @start: First index to retrieve from array.
		* @last: Last index to retrieve from array.
		*
		* During the iteration, @entry will have the value of the entry stored
		* in @xa at @index. You may modify @index during the iteration if you
		* want to skip or reprocess indices. It is safe to modify the array
		* during the iteration. At the end of the iteration, @entry will be set
		* to NULL and @index will have a value less than or equal to max.
		*
		* xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have
		* to handle your own locking with xas_for_each(), and if you have to unlock
		* after each iteration, it will also end up being O(n.log(n)).
		* xa_for_each_range() will spin if it hits a retry entry; if you intend to
		* see retry entries, you should use the xas_for_each() iterator instead.
		* The xas_for_each() iterator will expand into more inline code than
		* xa_for_each_range().
		*
		* Context: Any context. Takes and releases the RCU lock.
		*/
		#define xa_for_each_range(xa, index, entry, start, last) \
		for (index = start, \
		entry = xa_find(xa, &index, last, XA_PRESENT); \
		entry; \
		entry = xa_find_after(xa, &index, last, XA_PRESENT))

		/**
		* xa_for_each_start() - Iterate over a portion of an XArray.
		* @xa: XArray.
		@@ -440,10 +470,7 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark)
		* Context: Any context. Takes and releases the RCU lock.
		*/
		#define xa_for_each_start(xa, index, entry, start) \
		for (index = start, \
		entry = xa_find(xa, &index, ULONG_MAX, XA_PRESENT); \
		entry; \
		entry = xa_find_after(xa, &index, ULONG_MAX, XA_PRESENT))
		xa_for_each_range(xa, index, entry, start, ULONG_MAX)

		/**
		* xa_for_each() - Iterate over present entries in an XArray.

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