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authorMatthew Wilcox <willy@infradead.org>2019-01-02 21:57:03 +0300
committerMatthew Wilcox <willy@infradead.org>2019-01-07 06:12:58 +0300
commitb0606fed6eece16a421034eca0bbea9a08b90e91 (patch)
treef705b58760a60fce2d6f03a934a5038154505c1b /Documentation/core-api
parent76b4e52995654af260f14558e0e07b5b039ae202 (diff)
downloadlinux-b0606fed6eece16a421034eca0bbea9a08b90e91.tar.xz
XArray: Honour reserved entries in xa_insert
xa_insert() should treat reserved entries as occupied, not as available. Also, it should treat requests to insert a NULL pointer as a request to reserve the slot. Add xa_insert_bh() and xa_insert_irq() for completeness. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'Documentation/core-api')
-rw-r--r--Documentation/core-api/xarray.rst15
1 files changed, 9 insertions, 6 deletions
diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst
index 6a6d67acaf69..5d54b27c6eba 100644
--- a/Documentation/core-api/xarray.rst
+++ b/Documentation/core-api/xarray.rst
@@ -108,12 +108,13 @@ some, but not all of the other indices changing.
Sometimes you need to ensure that a subsequent call to :c:func:`xa_store`
will not need to allocate memory. The :c:func:`xa_reserve` function
-will store a reserved entry at the indicated index. Users of the normal
-API will see this entry as containing ``NULL``. If you do not need to
-use the reserved entry, you can call :c:func:`xa_release` to remove the
-unused entry. If another user has stored to the entry in the meantime,
-:c:func:`xa_release` will do nothing; if instead you want the entry to
-become ``NULL``, you should use :c:func:`xa_erase`.
+will store a reserved entry at the indicated index. Users of the
+normal API will see this entry as containing ``NULL``. If you do
+not need to use the reserved entry, you can call :c:func:`xa_release`
+to remove the unused entry. If another user has stored to the entry
+in the meantime, :c:func:`xa_release` will do nothing; if instead you
+want the entry to become ``NULL``, you should use :c:func:`xa_erase`.
+Using :c:func:`xa_insert` on a reserved entry will fail.
If all entries in the array are ``NULL``, the :c:func:`xa_empty` function
will return ``true``.
@@ -183,6 +184,8 @@ Takes xa_lock internally:
* :c:func:`xa_store_bh`
* :c:func:`xa_store_irq`
* :c:func:`xa_insert`
+ * :c:func:`xa_insert_bh`
+ * :c:func:`xa_insert_irq`
* :c:func:`xa_erase`
* :c:func:`xa_erase_bh`
* :c:func:`xa_erase_irq`