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| author | Matthew Wilcox <willy@infradead.org> | 2019-01-02 21:57:03 +0300 |
|---|---|---|
| committer | Matthew Wilcox <willy@infradead.org> | 2019-01-07 06:12:58 +0300 |
| commit | b0606fed6eece16a421034eca0bbea9a08b90e91 (patch) | |
| tree | f705b58760a60fce2d6f03a934a5038154505c1b /lib | |
| parent | 76b4e52995654af260f14558e0e07b5b039ae202 (diff) | |
| download | linux-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 'lib')
| -rw-r--r-- | lib/test_xarray.c | 8 | ||||
| -rw-r--r-- | lib/xarray.c | 41 |
2 files changed, 46 insertions, 3 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 6e0212a60b08..3cf17338b0a4 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -382,10 +382,12 @@ static noinline void check_reserve(struct xarray *xa) xa_erase_index(xa, 12345678); XA_BUG_ON(xa, !xa_empty(xa)); - /* And so does xa_insert */ + /* But xa_insert does not */ xa_reserve(xa, 12345678, GFP_KERNEL); - XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) != 0); - xa_erase_index(xa, 12345678); + XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) != + -EEXIST); + XA_BUG_ON(xa, xa_empty(xa)); + XA_BUG_ON(xa, xa_erase(xa, 12345678) != NULL); XA_BUG_ON(xa, !xa_empty(xa)); /* Can iterate through a reserved entry */ diff --git a/lib/xarray.c b/lib/xarray.c index bffa26b1f0d6..81c3171ddde9 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1440,6 +1440,47 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, EXPORT_SYMBOL(__xa_cmpxchg); /** + * __xa_insert() - Store this entry in the XArray if no entry is present. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * Inserting a NULL entry will store a reserved entry (like xa_reserve()) + * if no entry is present. Inserting will fail if a reserved entry is + * present, even though loading from this index will return NULL. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: 0 if the store succeeded. -EEXIST if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + void *curr; + + if (WARN_ON_ONCE(xa_is_advanced(entry))) + return -EINVAL; + if (!entry) + entry = XA_ZERO_ENTRY; + + do { + curr = xas_load(&xas); + if (!curr) { + xas_store(&xas, entry); + if (xa_track_free(xa)) + xas_clear_mark(&xas, XA_FREE_MARK); + } else { + xas_set_err(&xas, -EEXIST); + } + } while (__xas_nomem(&xas, gfp)); + + return xas_error(&xas); +} +EXPORT_SYMBOL(__xa_insert); + +/** * __xa_reserve() - Reserve this index in the XArray. * @xa: XArray. * @index: Index into array. |