From a3e4d3f97ec844de005a679585c04c5c03dfbdb6 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Mon, 31 Dec 2018 10:41:01 -0500 Subject: XArray: Redesign xa_alloc API It was too easy to forget to initialise the start index. Add an xa_limit data structure which can be used to pass min & max, and define a couple of special values for common cases. Also add some more tests cribbed from the IDR test suite. Change the return value from -ENOSPC to -EBUSY to match xa_insert(). Signed-off-by: Matthew Wilcox --- lib/xarray.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) (limited to 'lib/xarray.c') diff --git a/lib/xarray.c b/lib/xarray.c index 468fb7b7963f..c707388fb05e 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1615,23 +1615,23 @@ EXPORT_SYMBOL(xa_store_range); * __xa_alloc() - Find somewhere to store this entry in the XArray. * @xa: XArray. * @id: Pointer to ID. - * @max: Maximum ID to allocate (inclusive). + * @limit: Range for allocated ID. * @entry: New entry. * @gfp: Memory allocation flags. * - * Allocates an unused ID in the range specified by @id and @max. - * Updates the @id pointer with the index, then stores the entry at that - * index. A concurrent lookup will not see an uninitialised @id. + * Finds an empty entry in @xa between @limit.min and @limit.max, + * stores the index into the @id pointer, then stores the entry at + * that index. A concurrent lookup will not see an uninitialised @id. * * Context: Any context. Expects xa_lock to be held on entry. May * release and reacquire xa_lock if @gfp flags permit. - * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if - * there is no more space in the XArray. + * Return: 0 on success, -ENOMEM if memory could not be allocated or + * -EBUSY if there are no free entries in @limit. */ -int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) +int __xa_alloc(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, gfp_t gfp) { XA_STATE(xas, xa, 0); - int err; if (WARN_ON_ONCE(xa_is_advanced(entry))) return -EINVAL; @@ -1642,18 +1642,17 @@ int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) entry = XA_ZERO_ENTRY; do { - xas.xa_index = *id; - xas_find_marked(&xas, max, XA_FREE_MARK); + xas.xa_index = limit.min; + xas_find_marked(&xas, limit.max, XA_FREE_MARK); if (xas.xa_node == XAS_RESTART) - xas_set_err(&xas, -ENOSPC); + xas_set_err(&xas, -EBUSY); + else + *id = xas.xa_index; xas_store(&xas, entry); xas_clear_mark(&xas, XA_FREE_MARK); } while (__xas_nomem(&xas, gfp)); - err = xas_error(&xas); - if (!err) - *id = xas.xa_index; - return err; + return xas_error(&xas); } EXPORT_SYMBOL(__xa_alloc); -- cgit v1.2.3