From: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
To: Doug Ledford <dledford@redhat.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Hakon Bugge <haakon.bugge@oracle.com>,
Parav Pandit <parav@mellanox.com>,
Jack Morgenstein <jackm@dev.mellanox.co.il>,
Pravin Shedge <pravin.shedge4linux@gmail.com>,
Matthew Wilcox <mawilcox@microsoft.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jeff Layton <jlayton@kernel.org>, Wei Wang <wei.w.wang@intel.com>,
Chris Mi <chrism@mellanox.com>,
Eric Biggers <ebiggers@google.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Mel Gorman <mgorman@techsingularity.net>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/2] idr: Add ida_simple_get_cyclic
Date: Thu, 7 Jun 2018 12:52:07 +0200 [thread overview]
Message-ID: <20180607105208.16332-2-hans.westgaard.ry@oracle.com> (raw)
In-Reply-To: <20180607105208.16332-1-hans.westgaard.ry@oracle.com>
Orabug: 25571450
Signed-off-by: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
---
include/linux/idr.h | 8 +++++--
lib/idr.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+), 2 deletions(-)
diff --git a/include/linux/idr.h b/include/linux/idr.h
index e856f4e0ab35..f151ce89124a 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -218,10 +218,12 @@ DECLARE_PER_CPU(struct ida_bitmap *, ida_bitmap);
struct ida {
struct radix_tree_root ida_rt;
+ unsigned int ida_next;
};
-#define IDA_INIT(name) { \
- .ida_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER | GFP_NOWAIT), \
+#define IDA_INIT(name) { \
+ .ida_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER | GFP_NOWAIT), \
+ .ida_next = 0, \
}
#define DEFINE_IDA(name) struct ida name = IDA_INIT(name)
@@ -232,6 +234,8 @@ void ida_destroy(struct ida *ida);
int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
gfp_t gfp_mask);
+int ida_simple_get_cyclic(struct ida *ida, unsigned int start, unsigned int end,
+ gfp_t gfp_mask);
void ida_simple_remove(struct ida *ida, unsigned int id);
static inline void ida_init(struct ida *ida)
diff --git a/lib/idr.c b/lib/idr.c
index 823b813f08f8..3374c3fa4027 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -599,6 +599,72 @@ int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
return ret;
}
EXPORT_SYMBOL(ida_simple_get);
+/**
+ * ida_simple_get_cyclic - get a new id.
+ * @ida: the (initialized) ida.
+ * @start: the minimum id (inclusive, < 0x8000000)
+ * @end: the maximum id (exclusive, < 0x8000000 or 0)
+ * @gfp_mask: memory allocation flags
+ *
+ * Allocates an id in the range start <= id < end, or returns -ENOSPC.
+ * On memory allocation failure, returns -ENOMEM.
+ * The search for an unused id will start at the last id allocated and will
+ * wrap around to @start if no free ids are found before reaching @end.
+ *
+ * Compared to ida_get_new_above() this function does its own locking, and
+ * should be used unless there are special requirements.
+ *
+ * Use ida_simple_remove() to get rid of an id.
+ */
+int ida_simple_get_cyclic(struct ida *ida, unsigned int start, unsigned int end,
+ gfp_t gfp_mask)
+{
+ int ret, id, next;
+ unsigned int max;
+ unsigned long flags;
+
+ WARN_ON((int)start < 0);
+ WARN_ON((int)end < 0);
+
+ if (end == 0) {
+ max = 0x80000000;
+ } else {
+ WARN_ON(end < start);
+ max = end - 1;
+ }
+
+again:
+ if (!ida_pre_get(ida, gfp_mask))
+ return -ENOMEM;
+
+ spin_lock_irqsave(&simple_ida_lock, flags);
+ next = ida->ida_next;
+ if (next < start || next >= end)
+ next = start;
+
+ ret = ida_get_new_above(ida, next, &id);
+ if (likely(!ret)) {
+ if (unlikely(id >= max)) {
+ ida_remove(ida, id);
+ if (next == start) {
+ ret = -ENOSPC;
+ } else {
+ ida->ida_next = start;
+ spin_unlock_irqrestore(&simple_ida_lock, flags);
+ goto again;
+ }
+ } else {
+ ida->ida_next = id + 1;
+ ret = id;
+ }
+ }
+ spin_unlock_irqrestore(&simple_ida_lock, flags);
+
+ if (unlikely(ret == -EAGAIN))
+ goto again;
+ return ret;
+}
+EXPORT_SYMBOL(ida_simple_get_cyclic);
/**
* ida_simple_remove - remove an allocated id.
--
2.14.3
next prev parent reply other threads:[~2018-06-07 10:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-29 7:38 [PATCH] IB/mad: Use ID allocator routines to allocate agent number Hans Westgaard Ry
2018-05-29 8:54 ` Leon Romanovsky
2018-05-29 9:54 ` Leon Romanovsky
2018-05-30 8:18 ` jackm
2018-05-29 15:49 ` Jason Gunthorpe
2018-05-29 16:16 ` Håkon Bugge
2018-05-29 16:40 ` Jason Gunthorpe
2018-05-30 7:32 ` Håkon Bugge
2018-05-30 15:15 ` Jason Gunthorpe
2018-05-30 8:02 ` jackm
2018-05-30 12:22 ` Hans Westgaard Ry
2018-05-30 15:10 ` Jason Gunthorpe
2018-05-30 20:07 ` Håkon Bugge
2018-05-30 22:09 ` Jason Gunthorpe
2018-05-31 19:54 ` Håkon Bugge
2018-06-07 10:52 ` [PATCH v2 0/2] IB:mad " Hans Westgaard Ry
2018-06-07 10:52 ` Hans Westgaard Ry [this message]
2018-06-07 10:52 ` [PATCH v2 2/2] IB/mad: " Hans Westgaard Ry
2018-06-07 11:14 ` [PATCH v3 0/2] IB:mad " Hans Westgaard Ry
2018-06-07 11:14 ` [PATCH v3 1/2] idr: Add ida_simple_get_cyclic Hans Westgaard Ry
2018-06-07 18:50 ` Jason Gunthorpe
2018-06-07 11:14 ` [PATCH v3 2/2] IB/mad: Use ID allocator routines to allocate agent number Hans Westgaard Ry
2018-06-07 15:37 ` Matthew Wilcox
2018-06-07 17:59 ` Håkon Bugge
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