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Commit 1d9b2e1e authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

idr: remove length restriction from idr_layer->bitmap 



Currently, idr->bitmap is declared as an unsigned long which restricts
the number of bits an idr_layer can contain.  All bitops can handle
arbitrary positive integer bit number and there's no reason for this
restriction.

Declare idr_layer->bitmap using DECLARE_BITMAP() instead of a single
unsigned long.

* idr_layer->bitmap is now an array.  '&' dropped from params to
  bitops.

* Replaced "== IDR_FULL" tests with bitmap_full() and removed
  IDR_FULL.

* Replaced find_next_bit() on ~bitmap with find_next_zero_bit().

* Replaced "bitmap = 0" with bitmap_clear().

This patch doesn't (or at least shouldn't) introduce any behavior
changes.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e8c8d1bc

include/linux/idr.h

+1 −11
Original line number Original line Diff line number Diff line
@@ -19,18 +19,8 @@ 




#if BITS_PER_LONG == 32

#if BITS_PER_LONG == 32

# define IDR_BITS 5

# define IDR_BITS 5

# define IDR_FULL 0xfffffffful

/* We can only use two of the bits in the top level because there is

   only one possible bit in the top level (5 bits * 7 levels = 35

   bits, but you only use 31 bits in the id). */

# define TOP_LEVEL_FULL (IDR_FULL >> 30)

#elif BITS_PER_LONG == 64

#elif BITS_PER_LONG == 64

# define IDR_BITS 6

# define IDR_BITS 6

# define IDR_FULL 0xfffffffffffffffful

/* We can only use two of the bits in the top level because there is

   only one possible bit in the top level (6 bits * 6 levels = 36

   bits, but you only use 31 bits in the id). */

# define TOP_LEVEL_FULL (IDR_FULL >> 62)

#else

#else

# error "BITS_PER_LONG is not 32 or 64"

# error "BITS_PER_LONG is not 32 or 64"

#endif

#endif
@@ -39,7 +29,7 @@ 
#define IDR_MASK ((1 << IDR_BITS)-1)

#define IDR_MASK ((1 << IDR_BITS)-1)





struct idr_layer {

struct idr_layer {

	unsigned long		bitmap;	/* A zero bit means "space here" */

	DECLARE_BITMAP(bitmap, IDR_SIZE); /* A zero bit means "space here" */

	struct idr_layer __rcu	*ary[1<<IDR_BITS];

	struct idr_layer __rcu	*ary[1<<IDR_BITS];

	int			count;	/* When zero, we can release it */

	int			count;	/* When zero, we can release it */

	int			layer;	/* distance from leaf */

	int			layer;	/* distance from leaf */

lib/idr.c

+17 −17
Original line number Original line Diff line number Diff line
@@ -157,18 +157,18 @@ static void idr_mark_full(struct idr_layer **pa, int id) 
	struct idr_layer *p = pa[0];

	struct idr_layer *p = pa[0];

	int l = 0;

	int l = 0;





	__set_bit(id & IDR_MASK, &p->bitmap);

	__set_bit(id & IDR_MASK, p->bitmap);

	/*

	/*

	 * If this layer is full mark the bit in the layer above to

	 * If this layer is full mark the bit in the layer above to

	 * show that this part of the radix tree is full.  This may

	 * show that this part of the radix tree is full.  This may

	 * complete the layer above and require walking up the radix

	 * complete the layer above and require walking up the radix

	 * tree.

	 * tree.

	 */

	 */

	while (p->bitmap == IDR_FULL) {

	while (bitmap_full(p->bitmap, IDR_SIZE)) {

		if (!(p = pa[++l]))

		if (!(p = pa[++l]))

			break;

			break;

		id = id >> IDR_BITS;

		id = id >> IDR_BITS;

		__set_bit((id & IDR_MASK), &p->bitmap);

		__set_bit((id & IDR_MASK), p->bitmap);

	}

	}

}

}
@@ -221,7 +221,6 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, 
	int n, m, sh;

	int n, m, sh;

	struct idr_layer *p, *new;

	struct idr_layer *p, *new;

	int l, id, oid;

	int l, id, oid;

	unsigned long bm;





	id = *starting_id;

	id = *starting_id;

 restart:

 restart:
@@ -233,8 +232,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, 
		 * We run around this while until we reach the leaf node...

		 * We run around this while until we reach the leaf node...

		 */

		 */

		n = (id >> (IDR_BITS*l)) & IDR_MASK;

		n = (id >> (IDR_BITS*l)) & IDR_MASK;

		bm = ~p->bitmap;

		m = find_next_zero_bit(p->bitmap, IDR_SIZE, n);

		m = find_next_bit(&bm, IDR_SIZE, n);

		if (m == IDR_SIZE) {

		if (m == IDR_SIZE) {

			/* no space available go back to previous layer. */

			/* no space available go back to previous layer. */

			l++;

			l++;
@@ -326,7 +324,8 @@ static int idr_get_empty_slot(struct idr *idp, int starting_id, 
			for (new = p; p && p != idp->top; new = p) {

			for (new = p; p && p != idp->top; new = p) {

				p = p->ary[0];

				p = p->ary[0];

				new->ary[0] = NULL;

				new->ary[0] = NULL;

				new->bitmap = new->count = 0;

				new->count = 0;

				bitmap_clear(new->bitmap, 0, IDR_SIZE);

				__move_to_free_list(idp, new);

				__move_to_free_list(idp, new);

			}

			}

			spin_unlock_irqrestore(&idp->lock, flags);

			spin_unlock_irqrestore(&idp->lock, flags);
@@ -335,8 +334,8 @@ static int idr_get_empty_slot(struct idr *idp, int starting_id, 
		new->ary[0] = p;

		new->ary[0] = p;

		new->count = 1;

		new->count = 1;

		new->layer = layers-1;

		new->layer = layers-1;

		if (p->bitmap == IDR_FULL)

		if (bitmap_full(p->bitmap, IDR_SIZE))

			__set_bit(0, &new->bitmap);

			__set_bit(0, new->bitmap);

		p = new;

		p = new;

	}

	}

	rcu_assign_pointer(idp->top, p);

	rcu_assign_pointer(idp->top, p);
@@ -517,14 +516,14 @@ static void sub_remove(struct idr *idp, int shift, int id) 




	while ((shift > 0) && p) {

	while ((shift > 0) && p) {

		n = (id >> shift) & IDR_MASK;

		n = (id >> shift) & IDR_MASK;

		__clear_bit(n, &p->bitmap);

		__clear_bit(n, p->bitmap);

		*++paa = &p->ary[n];

		*++paa = &p->ary[n];

		p = p->ary[n];

		p = p->ary[n];

		shift -= IDR_BITS;

		shift -= IDR_BITS;

	}

	}

	n = id & IDR_MASK;

	n = id & IDR_MASK;

	if (likely(p != NULL && test_bit(n, &p->bitmap))){

	if (likely(p != NULL && test_bit(n, p->bitmap))) {

		__clear_bit(n, &p->bitmap);

		__clear_bit(n, p->bitmap);

		rcu_assign_pointer(p->ary[n], NULL);

		rcu_assign_pointer(p->ary[n], NULL);

		to_free = NULL;

		to_free = NULL;

		while(*paa && ! --((**paa)->count)){

		while(*paa && ! --((**paa)->count)){
@@ -567,7 +566,8 @@ void idr_remove(struct idr *idp, int id) 
		p = idp->top->ary[0];

		p = idp->top->ary[0];

		rcu_assign_pointer(idp->top, p);

		rcu_assign_pointer(idp->top, p);

		--idp->layers;

		--idp->layers;

		to_free->bitmap = to_free->count = 0;

		to_free->count = 0;

		bitmap_clear(to_free->bitmap, 0, IDR_SIZE);

		free_layer(to_free);

		free_layer(to_free);

	}

	}

	while (idp->id_free_cnt >= MAX_IDR_FREE) {

	while (idp->id_free_cnt >= MAX_IDR_FREE) {
@@ -827,7 +827,7 @@ void *idr_replace(struct idr *idp, void *ptr, int id) 
	}

	}





	n = id & IDR_MASK;

	n = id & IDR_MASK;

	if (unlikely(p == NULL || !test_bit(n, &p->bitmap)))

	if (unlikely(p == NULL || !test_bit(n, p->bitmap)))

		return ERR_PTR(-ENOENT);

		return ERR_PTR(-ENOENT);





	old_p = p->ary[n];

	old_p = p->ary[n];
@@ -1024,7 +1024,7 @@ void ida_remove(struct ida *ida, int id) 
	/* clear full bits while looking up the leaf idr_layer */

	/* clear full bits while looking up the leaf idr_layer */

	while ((shift > 0) && p) {

	while ((shift > 0) && p) {

		n = (idr_id >> shift) & IDR_MASK;

		n = (idr_id >> shift) & IDR_MASK;

		__clear_bit(n, &p->bitmap);

		__clear_bit(n, p->bitmap);

		p = p->ary[n];

		p = p->ary[n];

		shift -= IDR_BITS;

		shift -= IDR_BITS;

	}

	}
@@ -1033,7 +1033,7 @@ void ida_remove(struct ida *ida, int id) 
		goto err;

		goto err;





	n = idr_id & IDR_MASK;

	n = idr_id & IDR_MASK;

	__clear_bit(n, &p->bitmap);

	__clear_bit(n, p->bitmap);





	bitmap = (void *)p->ary[n];

	bitmap = (void *)p->ary[n];

	if (!test_bit(offset, bitmap->bitmap))

	if (!test_bit(offset, bitmap->bitmap))
@@ -1042,7 +1042,7 @@ void ida_remove(struct ida *ida, int id) 
	/* update bitmap and remove it if empty */

	/* update bitmap and remove it if empty */

	__clear_bit(offset, bitmap->bitmap);

	__clear_bit(offset, bitmap->bitmap);

	if (--bitmap->nr_busy == 0) {

	if (--bitmap->nr_busy == 0) {

		__set_bit(n, &p->bitmap);	/* to please idr_remove() */

		__set_bit(n, p->bitmap);	/* to please idr_remove() */

		idr_remove(&ida->idr, idr_id);

		idr_remove(&ida->idr, idr_id);

		free_bitmap(ida, bitmap);

		free_bitmap(ida, bitmap);

	}

	}