diff options
| -rw-r--r-- | include/linux/xarray.h | 36 | ||||
| -rw-r--r-- | lib/test_xarray.c | 28 | ||||
| -rw-r--r-- | lib/xarray.c | 6 |
3 files changed, 48 insertions, 22 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 687c150071a5..588733abd19d 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -131,6 +131,12 @@ static inline unsigned int xa_pointer_tag(void *entry) * xa_mk_internal() - Create an internal entry. * @v: Value to turn into an internal entry. * + * Internal entries are used for a number of purposes. Entries 0-255 are + * used for sibling entries (only 0-62 are used by the current code). 256 + * is used for the retry entry. 257 is used for the reserved / zero entry. + * Negative internal entries are used to represent errnos. Node pointers + * are also tagged as internal entries in some situations. + * * Context: Any context. * Return: An XArray internal entry corresponding to this value. */ @@ -163,6 +169,22 @@ static inline bool xa_is_internal(const void *entry) return ((unsigned long)entry & 3) == 2; } +#define XA_ZERO_ENTRY xa_mk_internal(257) + +/** + * xa_is_zero() - Is the entry a zero entry? + * @entry: Entry retrieved from the XArray + * + * The normal API will return NULL as the contents of a slot containing + * a zero entry. You can only see zero entries by using the advanced API. + * + * Return: %true if the entry is a zero entry. + */ +static inline bool xa_is_zero(const void *entry) +{ + return unlikely(entry == XA_ZERO_ENTRY); +} + /** * xa_is_err() - Report whether an XArray operation returned an error * @entry: Result from calling an XArray function @@ -1050,7 +1072,7 @@ int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) */ static inline void xa_release(struct xarray *xa, unsigned long index) { - xa_cmpxchg(xa, index, NULL, NULL, 0); + xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, 0); } /* Everything below here is the Advanced API. Proceed with caution. */ @@ -1210,18 +1232,6 @@ static inline bool xa_is_sibling(const void *entry) } #define XA_RETRY_ENTRY xa_mk_internal(256) -#define XA_ZERO_ENTRY xa_mk_internal(257) - -/** - * xa_is_zero() - Is the entry a zero entry? - * @entry: Entry retrieved from the XArray - * - * Return: %true if the entry is a zero entry. - */ -static inline bool xa_is_zero(const void *entry) -{ - return unlikely(entry == XA_ZERO_ENTRY); -} /** * xa_is_retry() - Is the entry a retry entry? diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 3eaa40ddc390..52f8ecff8c0c 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -361,6 +361,7 @@ static noinline void check_reserve(struct xarray *xa) { void *entry; unsigned long index; + int count; /* An array with a reserved entry is not empty */ XA_BUG_ON(xa, !xa_empty(xa)); @@ -377,15 +378,15 @@ static noinline void check_reserve(struct xarray *xa) xa_erase_index(xa, 12345678); XA_BUG_ON(xa, !xa_empty(xa)); - /* cmpxchg sees a reserved entry as NULL */ + /* cmpxchg sees a reserved entry as ZERO */ XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0); - XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, NULL, xa_mk_value(12345678), - GFP_NOWAIT) != NULL); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, XA_ZERO_ENTRY, + xa_mk_value(12345678), GFP_NOWAIT) != NULL); xa_release(xa, 12345678); xa_erase_index(xa, 12345678); XA_BUG_ON(xa, !xa_empty(xa)); - /* But xa_insert does not */ + /* xa_insert treats it as busy */ XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0); XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) != -EBUSY); @@ -398,9 +399,27 @@ static noinline void check_reserve(struct xarray *xa) XA_BUG_ON(xa, xa_reserve(xa, 6, GFP_KERNEL) != 0); xa_store_index(xa, 7, GFP_KERNEL); + count = 0; xa_for_each(xa, index, entry) { XA_BUG_ON(xa, index != 5 && index != 7); + count++; + } + XA_BUG_ON(xa, count != 2); + + /* If we free a reserved entry, we should be able to allocate it */ + if (xa->xa_flags & XA_FLAGS_ALLOC) { + u32 id; + + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(8), + XA_LIMIT(5, 10), GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 8); + + xa_release(xa, 6); + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(6), + XA_LIMIT(5, 10), GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 6); } + xa_destroy(xa); } @@ -1486,6 +1505,7 @@ static int xarray_checks(void) check_xas_erase(&array); check_cmpxchg(&array); check_reserve(&array); + check_reserve(&xa0); check_multi_store(&array); check_xa_alloc(); check_find(&array); diff --git a/lib/xarray.c b/lib/xarray.c index 89e37ac50850..b9a6cf42feee 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1429,16 +1429,12 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, if (WARN_ON_ONCE(xa_is_advanced(entry))) return XA_ERROR(-EINVAL); - if (xa_track_free(xa) && !entry) - entry = XA_ZERO_ENTRY; do { curr = xas_load(&xas); - if (curr == XA_ZERO_ENTRY) - curr = NULL; if (curr == old) { xas_store(&xas, entry); - if (xa_track_free(xa)) + if (xa_track_free(xa) && entry && !curr) xas_clear_mark(&xas, XA_FREE_MARK); } } while (__xas_nomem(&xas, gfp)); |