Commit 7fe6b987 authored by Yi Liu's avatar Yi Liu Committed by Jason Gunthorpe
Browse files

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: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Acked-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarYi Liu <yi.l.liu@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent d57a1fb3

include/linux/idr.h

+11 −0
Original line number Diff line number Diff line
@@ -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__ */

lib/idr.c

+67 −0
Original line number Diff line number Diff line
@@ -476,6 +476,73 @@ int ida_alloc_range(struct ida *ida, unsigned int min, unsigned int max, 
}

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.

lib/test_ida.c

+70 −0
Original line number Diff line number Diff line
@@ -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;