diff options
| -rw-r--r-- | include/linux/idr.h | 11 | ||||
| -rw-r--r-- | lib/idr.c | 67 | ||||
| -rw-r--r-- | lib/test_ida.c | 70 |
3 files changed, 148 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h index da5f5fa4a3a6..718f9b1b91af 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -257,6 +257,7 @@ struct ida { int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t); void ida_free(struct ida *, unsigned int id); void ida_destroy(struct ida *ida); +int ida_find_first_range(struct ida *ida, unsigned int min, unsigned int max); /** * ida_alloc() - Allocate an unused ID. @@ -328,4 +329,14 @@ static inline bool ida_is_empty(const struct ida *ida) { return xa_empty(&ida->xa); } + +static inline bool ida_exists(struct ida *ida, unsigned int id) +{ + return ida_find_first_range(ida, id, id) == id; +} + +static inline int ida_find_first(struct ida *ida) +{ + return ida_find_first_range(ida, 0, ~0); +} #endif /* __IDR_H__ */ diff --git a/lib/idr.c b/lib/idr.c index da36054c3ca0..e2adc457abb4 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -477,6 +477,73 @@ nospc: EXPORT_SYMBOL(ida_alloc_range); /** + * ida_find_first_range - Get the lowest used ID. + * @ida: IDA handle. + * @min: Lowest ID to get. + * @max: Highest ID to get. + * + * Get the lowest used ID between @min and @max, inclusive. The returned + * ID will not exceed %INT_MAX, even if @max is larger. + * + * Context: Any context. Takes and releases the xa_lock. + * Return: The lowest used ID, or errno if no used ID is found. + */ +int ida_find_first_range(struct ida *ida, unsigned int min, unsigned int max) +{ + unsigned long index = min / IDA_BITMAP_BITS; + unsigned int offset = min % IDA_BITMAP_BITS; + unsigned long *addr, size, bit; + unsigned long tmp = 0; + unsigned long flags; + void *entry; + int ret; + + if ((int)min < 0) + return -EINVAL; + if ((int)max < 0) + max = INT_MAX; + + xa_lock_irqsave(&ida->xa, flags); + + entry = xa_find(&ida->xa, &index, max / IDA_BITMAP_BITS, XA_PRESENT); + if (!entry) { + ret = -ENOENT; + goto err_unlock; + } + + if (index > min / IDA_BITMAP_BITS) + offset = 0; + if (index * IDA_BITMAP_BITS + offset > max) { + ret = -ENOENT; + goto err_unlock; + } + + if (xa_is_value(entry)) { + tmp = xa_to_value(entry); + addr = &tmp; + size = BITS_PER_XA_VALUE; + } else { + addr = ((struct ida_bitmap *)entry)->bitmap; + size = IDA_BITMAP_BITS; + } + + bit = find_next_bit(addr, size, offset); + + xa_unlock_irqrestore(&ida->xa, flags); + + if (bit == size || + index * IDA_BITMAP_BITS + bit > max) + return -ENOENT; + + return index * IDA_BITMAP_BITS + bit; + +err_unlock: + xa_unlock_irqrestore(&ida->xa, flags); + return ret; +} +EXPORT_SYMBOL(ida_find_first_range); + +/** * ida_free() - Release an allocated ID. * @ida: IDA handle. * @id: Previously allocated ID. diff --git a/lib/test_ida.c b/lib/test_ida.c index c80155a1956d..63078f8dc13f 100644 --- a/lib/test_ida.c +++ b/lib/test_ida.c @@ -189,6 +189,75 @@ static void ida_check_bad_free(struct ida *ida) IDA_BUG_ON(ida, !ida_is_empty(ida)); } +/* + * Check ida_find_first_range() and varriants. + */ +static void ida_check_find_first(struct ida *ida) +{ + /* IDA is empty; all of the below should be not exist */ + IDA_BUG_ON(ida, ida_exists(ida, 0)); + IDA_BUG_ON(ida, ida_exists(ida, 3)); + IDA_BUG_ON(ida, ida_exists(ida, 63)); + IDA_BUG_ON(ida, ida_exists(ida, 1023)); + IDA_BUG_ON(ida, ida_exists(ida, (1 << 20) - 1)); + + /* IDA contains a single value entry */ + IDA_BUG_ON(ida, ida_alloc_min(ida, 3, GFP_KERNEL) != 3); + IDA_BUG_ON(ida, ida_exists(ida, 0)); + IDA_BUG_ON(ida, !ida_exists(ida, 3)); + IDA_BUG_ON(ida, ida_exists(ida, 63)); + IDA_BUG_ON(ida, ida_exists(ida, 1023)); + IDA_BUG_ON(ida, ida_exists(ida, (1 << 20) - 1)); + + IDA_BUG_ON(ida, ida_alloc_min(ida, 63, GFP_KERNEL) != 63); + IDA_BUG_ON(ida, ida_exists(ida, 0)); + IDA_BUG_ON(ida, !ida_exists(ida, 3)); + IDA_BUG_ON(ida, !ida_exists(ida, 63)); + IDA_BUG_ON(ida, ida_exists(ida, 1023)); + IDA_BUG_ON(ida, ida_exists(ida, (1 << 20) - 1)); + + /* IDA contains a single bitmap */ + IDA_BUG_ON(ida, ida_alloc_min(ida, 1023, GFP_KERNEL) != 1023); + IDA_BUG_ON(ida, ida_exists(ida, 0)); + IDA_BUG_ON(ida, !ida_exists(ida, 3)); + IDA_BUG_ON(ida, !ida_exists(ida, 63)); + IDA_BUG_ON(ida, !ida_exists(ida, 1023)); + IDA_BUG_ON(ida, ida_exists(ida, (1 << 20) - 1)); + + /* IDA contains a tree */ + IDA_BUG_ON(ida, ida_alloc_min(ida, (1 << 20) - 1, GFP_KERNEL) != (1 << 20) - 1); + IDA_BUG_ON(ida, ida_exists(ida, 0)); + IDA_BUG_ON(ida, !ida_exists(ida, 3)); + IDA_BUG_ON(ida, !ida_exists(ida, 63)); + IDA_BUG_ON(ida, !ida_exists(ida, 1023)); + IDA_BUG_ON(ida, !ida_exists(ida, (1 << 20) - 1)); + + /* Now try to find first */ + IDA_BUG_ON(ida, ida_find_first(ida) != 3); + IDA_BUG_ON(ida, ida_find_first_range(ida, -1, 2) != -EINVAL); + IDA_BUG_ON(ida, ida_find_first_range(ida, 0, 2) != -ENOENT); // no used ID + IDA_BUG_ON(ida, ida_find_first_range(ida, 0, 3) != 3); + IDA_BUG_ON(ida, ida_find_first_range(ida, 1, 3) != 3); + IDA_BUG_ON(ida, ida_find_first_range(ida, 3, 3) != 3); + IDA_BUG_ON(ida, ida_find_first_range(ida, 2, 4) != 3); + IDA_BUG_ON(ida, ida_find_first_range(ida, 4, 3) != -ENOENT); // min > max, fail + IDA_BUG_ON(ida, ida_find_first_range(ida, 4, 60) != -ENOENT); // no used ID + IDA_BUG_ON(ida, ida_find_first_range(ida, 4, 64) != 63); + IDA_BUG_ON(ida, ida_find_first_range(ida, 63, 63) != 63); + IDA_BUG_ON(ida, ida_find_first_range(ida, 64, 1026) != 1023); + IDA_BUG_ON(ida, ida_find_first_range(ida, 1023, 1023) != 1023); + IDA_BUG_ON(ida, ida_find_first_range(ida, 1023, (1 << 20) - 1) != 1023); + IDA_BUG_ON(ida, ida_find_first_range(ida, 1024, (1 << 20) - 1) != (1 << 20) - 1); + IDA_BUG_ON(ida, ida_find_first_range(ida, (1 << 20), INT_MAX) != -ENOENT); + + ida_free(ida, 3); + ida_free(ida, 63); + ida_free(ida, 1023); + ida_free(ida, (1 << 20) - 1); + + IDA_BUG_ON(ida, !ida_is_empty(ida)); +} + static DEFINE_IDA(ida); static int ida_checks(void) @@ -202,6 +271,7 @@ static int ida_checks(void) ida_check_max(&ida); ida_check_conv(&ida); ida_check_bad_free(&ida); + ida_check_find_first(&ida); printk("IDA: %u of %u tests passed\n", tests_passed, tests_run); return (tests_run != tests_passed) ? 0 : -EINVAL; |