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authorMatthew Wilcox <willy@infradead.org>2018-11-05 16:15:56 -0500
committerMatthew Wilcox <willy@infradead.org>2018-11-05 16:38:09 -0500
commitd9c480435add8257f9069941f0e6196647f6d746 (patch)
tree8e46a69188df371b24c83cf2181d42971336344b /lib/xarray.c
parent611f318637daa5710a1d7a0e7dc6cda23914094a (diff)
downloadlinux-d9c480435add8257f9069941f0e6196647f6d746.tar.bz2
XArray: Handle NULL pointers differently for allocation
For allocating XArrays, it makes sense to distinguish beteen erasing an entry and storing NULL. Storing NULL keeps the index allocated with a NULL pointer associated with it while xa_erase() frees the index. Some existing IDR users rely on this ability. Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'lib/xarray.c')
-rw-r--r--lib/xarray.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/lib/xarray.c b/lib/xarray.c
index a9d28013f9dc..c3e2084aa313 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1382,10 +1382,12 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
+ if (xa_track_free(xa) && !entry)
+ entry = XA_ZERO_ENTRY;
do {
curr = xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
+ if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
} while (__xas_nomem(&xas, gfp));
@@ -1446,6 +1448,8 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
+ if (xa_track_free(xa) && !entry)
+ entry = XA_ZERO_ENTRY;
do {
curr = xas_load(&xas);
@@ -1453,7 +1457,7 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
curr = NULL;
if (curr == old) {
xas_store(&xas, entry);
- if (xa_track_free(xa) && entry)
+ if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
}
} while (__xas_nomem(&xas, gfp));
@@ -1487,8 +1491,11 @@ int __xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
do {
curr = xas_load(&xas);
- if (!curr)
+ if (!curr) {
xas_store(&xas, XA_ZERO_ENTRY);
+ if (xa_track_free(xa))
+ xas_clear_mark(&xas, XA_FREE_MARK);
+ }
} while (__xas_nomem(&xas, gfp));
return xas_error(&xas);