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authorLinus Torvalds <torvalds@linux-foundation.org>2022-04-01 13:40:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-04-01 13:40:44 -0700
commit5a3fe95d76999980a106f661bf70379818a77701 (patch)
tree65bb4a0514adfb5ca49043236c2dcfb0898f38aa /Documentation
parenta3dfc532b8731843c12bdc45e804eacc47e51e50 (diff)
parent3ed4bb77156da0bc732847c8c9df92454c1fbeea (diff)
Merge tag 'xarray-5.18' of git://git.infradead.org/users/willy/xarray
Pull XArray updates from Matthew Wilcox: - Documentation update - Fix test-suite build after move of bitmap.h - Fix xas_create_range() when a large entry is already present - Fix xas_split() of a shadow entry * tag 'xarray-5.18' of git://git.infradead.org/users/willy/xarray: XArray: Update the LRU list in xas_split() XArray: Fix xas_create_range() when multi-order entry present XArray: Include bitmap.h from xarray.h XArray: Document the locking requirement for the xa_state
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/core-api/xarray.rst14
1 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst
index a137a0e6d068..77e0ece2b1d6 100644
--- a/Documentation/core-api/xarray.rst
+++ b/Documentation/core-api/xarray.rst
@@ -315,11 +315,15 @@ indeed the normal API is implemented in terms of the advanced API. The
advanced API is only available to modules with a GPL-compatible license.
The advanced API is based around the xa_state. This is an opaque data
-structure which you declare on the stack using the XA_STATE()
-macro. This macro initialises the xa_state ready to start walking
-around the XArray. It is used as a cursor to maintain the position
-in the XArray and let you compose various operations together without
-having to restart from the top every time.
+structure which you declare on the stack using the XA_STATE() macro.
+This macro initialises the xa_state ready to start walking around the
+XArray. It is used as a cursor to maintain the position in the XArray
+and let you compose various operations together without having to restart
+from the top every time. The contents of the xa_state are protected by
+the rcu_read_lock() or the xas_lock(). If you need to drop whichever of
+those locks is protecting your state and tree, you must call xas_pause()
+so that future calls do not rely on the parts of the state which were
+left unprotected.
The xa_state is also used to store errors. You can call
xas_error() to retrieve the error. All operations check whether