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| author | Matthew Wilcox <willy@infradead.org> | 2018-10-01 21:54:59 +0300 |
|---|---|---|
| committer | Matthew Wilcox <willy@infradead.org> | 2018-10-21 17:46:00 +0300 |
| commit | 9f14d4f1f1045f161fd4db8a8e194b7825c2874a (patch) | |
| tree | fcc3e832d34116dec5dfe2e36525cbdb81cc47c8 /lib/test_xarray.c | |
| parent | 2264f5132fe45571139727ebdeb78696b35d1506 (diff) | |
| download | linux-9f14d4f1f1045f161fd4db8a8e194b7825c2874a.tar.xz | |
xarray: Add xa_reserve and xa_release
This function reserves a slot in the XArray for users which need
to acquire multiple locks before storing their entry in the tree and
so cannot use a plain xa_store().
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Diffstat (limited to 'lib/test_xarray.c')
| -rw-r--r-- | lib/test_xarray.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index 703370015d10..6aafd411a5c3 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -259,6 +259,45 @@ static noinline void check_cmpxchg(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); } +static noinline void check_reserve(struct xarray *xa) +{ + void *entry; + unsigned long index = 0; + + /* An array with a reserved entry is not empty */ + XA_BUG_ON(xa, !xa_empty(xa)); + xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_empty(xa)); + XA_BUG_ON(xa, xa_load(xa, 12345678)); + xa_release(xa, 12345678); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Releasing a used entry does nothing */ + xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_NOWAIT) != NULL); + xa_release(xa, 12345678); + xa_erase_index(xa, 12345678); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* cmpxchg sees a reserved entry as NULL */ + xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, NULL, xa_mk_value(12345678), + GFP_NOWAIT) != NULL); + xa_release(xa, 12345678); + xa_erase_index(xa, 12345678); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Can iterate through a reserved entry */ + xa_store_index(xa, 5, GFP_KERNEL); + xa_reserve(xa, 6, GFP_KERNEL); + xa_store_index(xa, 7, GFP_KERNEL); + + xa_for_each(xa, entry, index, ULONG_MAX, XA_PRESENT) { + XA_BUG_ON(xa, index != 5 && index != 7); + } + xa_destroy(xa); +} + static noinline void check_xas_erase(struct xarray *xa) { XA_STATE(xas, xa, 0); @@ -808,6 +847,7 @@ static int xarray_checks(void) check_xa_shrink(&array); check_xas_erase(&array); check_cmpxchg(&array); + check_reserve(&array); check_multi_store(&array); check_find(&array); check_destroy(&array); |