Messages in this thread Patch in this message | | | Date | Thu, 13 Apr 2006 16:35:46 -0400 | From | Jeff Mahoney <> | Subject | [PATCH 01/08] idr: add idr_replace method for replacing pointers |
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This patch adds an idr_replace() method to the IDR library for replacing a pointer already present in the IDR. Rather than do a remove/add pair, this function simply updates the pointer for an ID.
Signed-off-by: Jeff Mahoney <jeffm@suse.com> -- include/linux/idr.h | 1 + lib/idr.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+)
diff -ruNpX ../dontdiff linux-2.6.16-staging1/include/linux/idr.h linux-2.6.16-staging2/include/linux/idr.h --- linux-2.6.16-staging1/include/linux/idr.h 2006-01-02 22:21:10.000000000 -0500 +++ linux-2.6.16-staging2/include/linux/idr.h 2006-04-13 16:18:14.000000000 -0400 @@ -78,6 +78,7 @@ void *idr_find(struct idr *idp, int id); int idr_pre_get(struct idr *idp, gfp_t gfp_mask); int idr_get_new(struct idr *idp, void *ptr, int *id); int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id); +int idr_replace(struct idr *idp, void *ptr, int id); void idr_remove(struct idr *idp, int id); void idr_destroy(struct idr *idp); void idr_init(struct idr *idp); diff -ruNpX ../dontdiff linux-2.6.16-staging1/lib/idr.c linux-2.6.16-staging2/lib/idr.c --- linux-2.6.16-staging1/lib/idr.c 2006-01-02 22:21:10.000000000 -0500 +++ linux-2.6.16-staging2/lib/idr.c 2006-04-13 16:18:14.000000000 -0400 @@ -390,6 +390,43 @@ void *idr_find(struct idr *idp, int id) } EXPORT_SYMBOL(idr_find); +/** + * idr_replace - replace pointer for given id + * @idp: idr handle + * @ptr: pointer you want associated with the ide + * @id: lookup key + * + * Replace the pointer registered with the id. A -ENOENT + * return indicates that @id was not found. + * + * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove(). + */ +int idr_replace(struct idr *idp, void *ptr, int id) +{ + int n; + struct idr_layer *p; + int shift = (idp->layers - 1) * IDR_BITS; + + n = idp->layers * IDR_BITS; + p = idp->top; + + id &= MAX_ID_MASK; + + while ((shift > 0) && p) { + n = (id >> shift) & IDR_MASK; + p = p->ary[n]; + shift -= IDR_BITS; + } + + n = id & IDR_MASK; + if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) + return -ENOENT; + + p->ary[n] = ptr; + return 0; +} +EXPORT_SYMBOL(idr_replace); + static void idr_cache_ctor(void * idr_layer, kmem_cache_t *idr_layer_cache, unsigned long flags) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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