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ida: Add ida_find_first_range() 

There is no helpers for user to check if a given ID is allocated or not,
neither a helper to loop all the allocated IDs in an IDA and do something
for cleanup. With the two needs, a helper to get the lowest allocated ID
of a range and two variants based on it.

Caller can check if a given ID is allocated or not by:

	bool ida_exists(struct ida *ida, unsigned int id)

Caller can iterate all allocated IDs by:

	int id;
	while ((id = ida_find_first(&pasid_ida)) >= 0) {
		//anything to do with the allocated ID
		ida_free(pasid_ida, pasid);
	}

Link: https://patch.msgid.link/r/20250321180143.8468-2-yi.l.liu@intel.com
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Yi Liu 2025-03-21 11:01:39 -07:00 committed by Jason Gunthorpe
parent d57a1fb342
commit 7fe6b98716
3 changed files with 148 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
include/linux/idr.h
View File

@ -257,6 +257,7 @@ struct ida {
int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t); int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t);
void ida_free(struct ida *, unsigned int id); void ida_free(struct ida *, unsigned int id);
void ida_destroy(struct ida *ida); 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. * 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); 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__ */ #endif /* __IDR_H__ */

67
lib/idr.c
View File

@ -476,6 +476,73 @@ int ida_alloc_range(struct ida *ida, unsigned int min, unsigned int max,
} }
EXPORT_SYMBOL(ida_alloc_range); 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_free() - Release an allocated ID.
* @ida: IDA handle. * @ida: IDA handle.

70
lib/test_ida.c
View File

@ -189,6 +189,75 @@ static void ida_check_bad_free(struct ida *ida)
IDA_BUG_ON(ida, !ida_is_empty(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 DEFINE_IDA(ida);
static int ida_checks(void) static int ida_checks(void)
@ -202,6 +271,7 @@ static int ida_checks(void)
ida_check_max(&ida); ida_check_max(&ida);
ida_check_conv(&ida); ida_check_conv(&ida);
ida_check_bad_free(&ida); ida_check_bad_free(&ida);
ida_check_find_first(&ida);
printk("IDA: %u of %u tests passed\n", tests_passed, tests_run); printk("IDA: %u of %u tests passed\n", tests_passed, tests_run);
return (tests_run != tests_passed) ? 0 : -EINVAL; return (tests_run != tests_passed) ? 0 : -EINVAL;