Like cmpxchg(), xa_cmpxchg will only store to the index if the current entry matches the old entry. It returns the current entry, which is usually more useful than the errno returned by radix_tree_insert(). For the users who really only want the errno, the xa_insert() wrapper provides a more convenient calling convention.
Showing the changes to lib/test_xarray.c (1 of 3 files). Show all
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| @@ -198,6 +198,25 @@ static noinline void check_xa_shrink(struct xarray *xa) · 197 unmodified lines | |||
| 198 | XA_BUG_ON(xa, !xa_empty(xa)); | 198 | XA_BUG_ON(xa, !xa_empty(xa)); |
| 199 | } | 199 | } |
| 200 | 200 | ||
| 201 | static noinline void check_cmpxchg(struct xarray *xa) | ||
| 202 | { | ||
| 203 | void *FIVE = xa_mk_value(5); | ||
| 204 | void *SIX = xa_mk_value(6); | ||
| 205 | void *LOTS = xa_mk_value(12345678); | ||
| 206 | |||
| 207 | XA_BUG_ON(xa, !xa_empty(xa)); | ||
| 208 | XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_KERNEL) != NULL); | ||
| 209 | XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EEXIST); | ||
| 210 | XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, SIX, FIVE, GFP_KERNEL) != LOTS); | ||
| 211 | XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, LOTS, FIVE, GFP_KERNEL) != LOTS); | ||
| 212 | XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, FIVE, LOTS, GFP_KERNEL) != FIVE); | ||
| 213 | XA_BUG_ON(xa, xa_cmpxchg(xa, 5, FIVE, NULL, GFP_KERNEL) != NULL); | ||
| 214 | XA_BUG_ON(xa, xa_cmpxchg(xa, 5, NULL, FIVE, GFP_KERNEL) != NULL); | ||
| 215 | xa_erase_index(xa, 12345678); | ||
| 216 | xa_erase_index(xa, 5); | ||
| 217 | XA_BUG_ON(xa, !xa_empty(xa)); | ||
| 218 | } | ||
| 219 | |||
| 201 | static noinline void check_multi_store(struct xarray *xa) | 220 | static noinline void check_multi_store(struct xarray *xa) |
| 202 | { | 221 | { |
| 203 | #ifdef CONFIG_XARRAY_MULTI | 222 | #ifdef CONFIG_XARRAY_MULTI |
| @@ -274,6 +293,7 @@ static int xarray_checks(void) · 70 unmodified lines | |||
| 274 | check_xa_load(&array); | 293 | check_xa_load(&array); |
| 275 | check_xa_mark(&array); | 294 | check_xa_mark(&array); |
| 276 | check_xa_shrink(&array); | 295 | check_xa_shrink(&array); |
| 296 | check_cmpxchg(&array); | ||
| 277 | check_multi_store(&array); | 297 | check_multi_store(&array); |
| 278 | 298 | ||
| 279 | printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); | 299 | printk("XArray: %u of %u tests passed\n", tests_passed, tests_run); |