From 12d1b4393e0d8df36b2646a5e512f0513fb532d2 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 27 Feb 2013 17:03:53 -0800 Subject: [PATCH] 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: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/idr.h | 6 ------ lib/idr.c | 35 +++++++++++++++++++++++------------ 2 files changed, 23 insertions(+), 18 deletions(-) diff --git a/include/linux/idr.h b/include/linux/idr.h index ff44bc83f3cb..837f152b1383 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -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) diff --git a/lib/idr.c b/lib/idr.c index 282841b5a561..bde6eecb0e87 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -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;