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Commit 12d1b439 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

idr: remove _idr_rc_to_errno() hack 



idr uses -1, IDR_NEED_TO_GROW and IDR_NOMORE_SPACE to communicate
exception conditions internally.  The return value is later translated
to errno values using _idr_rc_to_errno().

This is confusing.  Drop the custom ones and consistently use -EAGAIN
for "tree needs to grow", -ENOMEM for "need more memory" and -ENOSPC for
"ran out of ID space".

Due to the weird memory preloading mechanism, [ra]_get_new*() return
-EAGAIN on memory shortage, so we need to substitute -ENOMEM w/
-EAGAIN on those interface functions.  They'll eventually be cleaned
up and the translations will go away.

This patch doesn't introduce any functional changes.

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 49038ef4

include/linux/idr.h

+0 −6
Original line number Diff line number Diff line
@@ -70,12 +70,6 @@ struct idr { 
}

#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)



/* Actions to be taken after a call to _idr_sub_alloc */

#define IDR_NEED_TO_GROW -2

#define IDR_NOMORE_SPACE -3



#define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC)



/**

 * DOC: idr sync

 * idr synchronization (stolen from radix-tree.h)

lib/idr.c

+23 −12
Original line number Diff line number Diff line
@@ -133,6 +133,21 @@ int idr_pre_get(struct idr *idp, gfp_t gfp_mask) 
}

EXPORT_SYMBOL(idr_pre_get);



/**

 * sub_alloc - try to allocate an id without growing the tree depth

 * @idp: idr handle

 * @starting_id: id to start search at

 * @id: pointer to the allocated handle

 * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer

 *

 * Allocate an id in range [@starting_id, INT_MAX] from @idp without

 * growing its depth.  Returns

 *

 *  the allocated id >= 0 if successful,

 *  -EAGAIN if the tree needs to grow for allocation to succeed,

 *  -ENOSPC if the id space is exhausted,

 *  -ENOMEM if more idr_layers need to be allocated.

 */

static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)

{

	int n, m, sh;
@@ -161,7 +176,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) 
			/* if already at the top layer, we need to grow */

			if (id >= 1 << (idp->layers * IDR_BITS)) {

				*starting_id = id;

				return IDR_NEED_TO_GROW;

				return -EAGAIN;

			}

			p = pa[l];

			BUG_ON(!p);
@@ -180,7 +195,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) 
			id = ((id >> sh) ^ n ^ m) << sh;

		}

		if ((id >= MAX_IDR_BIT) || (id < 0))

			return IDR_NOMORE_SPACE;

			return -ENOSPC;

		if (l == 0)

			break;

		/*
@@ -189,7 +204,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) 
		if (!p->ary[m]) {

			new = get_from_free_list(idp);

			if (!new)

				return -1;

				return -ENOMEM;

			new->layer = l-1;

			rcu_assign_pointer(p->ary[m], new);

			p->count++;
@@ -215,7 +230,7 @@ static int idr_get_empty_slot(struct idr *idp, int starting_id, 
	layers = idp->layers;

	if (unlikely(!p)) {

		if (!(p = get_from_free_list(idp)))

			return -1;

			return -ENOMEM;

		p->layer = 0;

		layers = 1;

	}
@@ -246,7 +261,7 @@ static int idr_get_empty_slot(struct idr *idp, int starting_id, 
				__move_to_free_list(idp, new);

			}

			spin_unlock_irqrestore(&idp->lock, flags);

			return -1;

			return -ENOMEM;

		}

		new->ary[0] = p;

		new->count = 1;
@@ -258,7 +273,7 @@ static int idr_get_empty_slot(struct idr *idp, int starting_id, 
	rcu_assign_pointer(idp->top, p);

	idp->layers = layers;

	v = sub_alloc(idp, &id, pa);

	if (v == IDR_NEED_TO_GROW)

	if (v == -EAGAIN)

		goto build_up;

	return(v);

}
@@ -306,12 +321,8 @@ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) 
	int rv;



	rv = idr_get_new_above_int(idp, ptr, starting_id);

	/*

	 * This is a cheap hack until the IDR code can be fixed to

	 * return proper error values.

	 */

	if (rv < 0)

		return _idr_rc_to_errno(rv);

		return rv == -ENOMEM ? -EAGAIN : rv;

	*id = rv;

	return 0;

}
@@ -766,7 +777,7 @@ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) 
	/* get vacant slot */

	t = idr_get_empty_slot(&ida->idr, idr_id, pa);

	if (t < 0)

		return _idr_rc_to_errno(t);

		return t == -ENOMEM ? -EAGAIN : t;



	if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT)

		return -ENOSPC;