diff options
Diffstat (limited to 'lib/idr.c')
| -rw-r--r-- | lib/idr.c | 123 |
1 files changed, 60 insertions, 63 deletions
diff --git a/lib/idr.c b/lib/idr.c index 73f4d53c02f3..cca4b9302a71 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -106,8 +106,14 @@ static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) if (layer_idr) return get_from_free_list(layer_idr); - /* try to allocate directly from kmem_cache */ - new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); + /* + * Try to allocate directly from kmem_cache. We want to try this + * before preload buffer; otherwise, non-preloading idr_alloc() + * users will end up taking advantage of preloading ones. As the + * following is allowed to fail for preloaded cases, suppress + * warning this time. + */ + new = kmem_cache_zalloc(idr_layer_cache, gfp_mask | __GFP_NOWARN); if (new) return new; @@ -115,18 +121,24 @@ static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) * Try to fetch one from the per-cpu preload buffer if in process * context. See idr_preload() for details. */ - if (in_interrupt()) - return NULL; - - preempt_disable(); - new = __this_cpu_read(idr_preload_head); - if (new) { - __this_cpu_write(idr_preload_head, new->ary[0]); - __this_cpu_dec(idr_preload_cnt); - new->ary[0] = NULL; + if (!in_interrupt()) { + preempt_disable(); + new = __this_cpu_read(idr_preload_head); + if (new) { + __this_cpu_write(idr_preload_head, new->ary[0]); + __this_cpu_dec(idr_preload_cnt); + new->ary[0] = NULL; + } + preempt_enable(); + if (new) + return new; } - preempt_enable(); - return new; + + /* + * Both failed. Try kmem_cache again w/o adding __GFP_NOWARN so + * that memory allocation failure warning is printed as intended. + */ + return kmem_cache_zalloc(idr_layer_cache, gfp_mask); } static void idr_layer_rcu_free(struct rcu_head *head) @@ -184,20 +196,7 @@ static void idr_mark_full(struct idr_layer **pa, int id) } } -/** - * idr_pre_get - reserve resources for idr allocation - * @idp: idr handle - * @gfp_mask: memory allocation flags - * - * This function should be called prior to calling the idr_get_new* functions. - * It preallocates enough memory to satisfy the worst possible allocation. The - * caller should pass in GFP_KERNEL if possible. This of course requires that - * no spinning locks be held. - * - * If the system is REALLY out of memory this function returns %0, - * otherwise %1. - */ -int idr_pre_get(struct idr *idp, gfp_t gfp_mask) +int __idr_pre_get(struct idr *idp, gfp_t gfp_mask) { while (idp->id_free_cnt < MAX_IDR_FREE) { struct idr_layer *new; @@ -208,13 +207,12 @@ int idr_pre_get(struct idr *idp, gfp_t gfp_mask) } return 1; } -EXPORT_SYMBOL(idr_pre_get); +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 * @gfp_mask: allocation mask for idr_layer_alloc() * @layer_idr: optional idr passed to idr_layer_alloc() @@ -376,25 +374,7 @@ static void idr_fill_slot(struct idr *idr, void *ptr, int id, idr_mark_full(pa, id); } -/** - * idr_get_new_above - allocate new idr entry above or equal to a start id - * @idp: idr handle - * @ptr: pointer you want associated with the id - * @starting_id: id to start search at - * @id: pointer to the allocated handle - * - * This is the allocate id function. It should be called with any - * required locks. - * - * If allocation from IDR's private freelist fails, idr_get_new_above() will - * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill - * IDR's preallocation and then retry the idr_get_new_above() call. - * - * If the idr is full idr_get_new_above() will return %-ENOSPC. - * - * @id returns a value in the range @starting_id ... %0x7fffffff - */ -int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) +int __idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) { struct idr_layer *pa[MAX_IDR_LEVEL + 1]; int rv; @@ -407,7 +387,7 @@ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) *id = rv; return 0; } -EXPORT_SYMBOL(idr_get_new_above); +EXPORT_SYMBOL(__idr_get_new_above); /** * idr_preload - preload for idr_alloc() @@ -515,6 +495,33 @@ int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) } EXPORT_SYMBOL_GPL(idr_alloc); +/** + * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion + * @idr: the (initialized) idr + * @ptr: pointer to be associated with the new id + * @start: the minimum id (inclusive) + * @end: the maximum id (exclusive, <= 0 for max) + * @gfp_mask: memory allocation flags + * + * Essentially the same as idr_alloc, but prefers to allocate progressively + * higher ids if it can. If the "cur" counter wraps, then it will start again + * at the "start" end of the range and allocate one that has already been used. + */ +int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, + gfp_t gfp_mask) +{ + int id; + + id = idr_alloc(idr, ptr, max(start, idr->cur), end, gfp_mask); + if (id == -ENOSPC) + id = idr_alloc(idr, ptr, start, end, gfp_mask); + + if (likely(id >= 0)) + idr->cur = id + 1; + return id; +} +EXPORT_SYMBOL(idr_alloc_cyclic); + static void idr_remove_warning(int id) { printk(KERN_WARNING @@ -569,8 +576,7 @@ void idr_remove(struct idr *idp, int id) struct idr_layer *p; struct idr_layer *to_free; - /* see comment in idr_find_slowpath() */ - if (WARN_ON_ONCE(id < 0)) + if (id < 0) return; sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); @@ -667,15 +673,7 @@ void *idr_find_slowpath(struct idr *idp, int id) int n; struct idr_layer *p; - /* - * If @id is negative, idr_find() used to ignore the sign bit and - * performed lookup with the rest of bits, which is weird and can - * lead to very obscure bugs. We're now returning NULL for all - * negative IDs but just in case somebody was depending on the sign - * bit being ignored, let's trigger WARN_ON_ONCE() so that they can - * be detected and fixed. WARN_ON_ONCE() can later be removed. - */ - if (WARN_ON_ONCE(id < 0)) + if (id < 0) return NULL; p = rcu_dereference_raw(idp->top); @@ -824,8 +822,7 @@ void *idr_replace(struct idr *idp, void *ptr, int id) int n; struct idr_layer *p, *old_p; - /* see comment in idr_find_slowpath() */ - if (WARN_ON_ONCE(id < 0)) + if (id < 0) return ERR_PTR(-EINVAL); p = idp->top; @@ -918,7 +915,7 @@ static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) int ida_pre_get(struct ida *ida, gfp_t gfp_mask) { /* allocate idr_layers */ - if (!idr_pre_get(&ida->idr, gfp_mask)) + if (!__idr_pre_get(&ida->idr, gfp_mask)) return 0; /* allocate free_bitmap */ |