This path replaces physically contiguous memory arrays
allocated using kmalloc_array() with flexible arrays.
This enables to avoid memory allocation failures on the
systems under a memory stress.
Signed-off-by: Oleg Babin <obabin@xxxxxxxxxxxxx>
---
include/net/sctp/structs.h | 1 +
net/sctp/stream.c | 78 +++++++++++++++++++++++++++++++++++-----------
2 files changed, 61 insertions(+), 18 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index dc48c8e2b293..884d33965e89 100644
--- a/include/net/sctp/structs.h
+++ b/include/net/sctp/structs.h
@@ -57,6 +57,7 @@
#include <linux/atomic.h> /* This gets us atomic counters. */
#include <linux/skbuff.h> /* We need sk_buff_head. */
#include <linux/workqueue.h> /* We need tq_struct. */
+#include <linux/flex_array.h> /* We need flex_array. */
#include <linux/sctp.h> /* We need sctp* header structs. */
#include <net/sctp/auth.h> /* We need auth specific structs */
#include <net/ip.h> /* For inet_skb_parm */
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 56fadeec7cba..3e55db1a38d0 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -40,13 +40,60 @@
struct sctp_stream_out *sctp_stream_out(const struct sctp_stream *stream,
__u16 sid)
{
- return ((struct sctp_stream_out *)(stream->out)) + sid;
+ return flex_array_get(stream->out, sid);
}
struct sctp_stream_in *sctp_stream_in(const struct sctp_stream *stream,
__u16 sid)
{
- return ((struct sctp_stream_in *)(stream->in)) + sid;
+ return flex_array_get(stream->in, sid);
+}
+
+static struct flex_array *fa_alloc(size_t elem_size, size_t elem_count,
+ gfp_t gfp)
+{
+ struct flex_array *result;
+ int err;
+
+ result = flex_array_alloc(elem_size, elem_count, gfp);
+ if (result) {
+ err = flex_array_prealloc(result, 0, elem_count, gfp);
+ if (err) {
+ flex_array_free(result);
+ result = NULL;
+ }
+ }
+
+ return result;
+}
+
+static void fa_free(struct flex_array *fa)
+{
+ if (fa)
+ flex_array_free(fa);
+}
+
+static void fa_copy(struct flex_array *fa, struct flex_array *from,
+ size_t index, size_t count)
+{
+ void *elem;
+
+ while (count--) {
+ elem = flex_array_get(from, index);
+ flex_array_put(fa, index, elem, 0);
+ index++;
+ }
+}
+
+static void fa_zero(struct flex_array *fa, size_t index, size_t count)
+{
+ void *elem;
+
+ while (count--) {
+ elem = flex_array_get(fa, index);
+ memset(elem, 0, fa->element_size);
+ index++;
+ }
}
/* Migrates chunks from stream queues to new stream queues if needed,
@@ -106,19 +153,17 @@ static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
struct flex_array *out;
size_t elem_size = sizeof(struct sctp_stream_out);
- out = kmalloc_array(outcnt, elem_size, gfp);
+ out = fa_alloc(elem_size, outcnt, gfp);
if (!out)
return -ENOMEM;
if (stream->out) {
- memcpy(out, stream->out, min(outcnt, stream->outcnt) *
- elem_size);
- kfree(stream->out);
+ fa_copy(out, stream->out, 0, min(outcnt, stream->outcnt));
+ fa_free(stream->out);
}
if (outcnt > stream->outcnt)
- memset(((struct sctp_stream_out *)out) + stream->outcnt, 0,
- (outcnt - stream->outcnt) * elem_size);
+ fa_zero(out, stream->outcnt, (outcnt - stream->outcnt));
stream->out = out;
@@ -131,20 +176,17 @@ static int sctp_stream_alloc_in(struct sctp_stream *stream, __u16 incnt,
struct flex_array *in;
size_t elem_size = sizeof(struct sctp_stream_in);
- in = kmalloc_array(incnt, elem_size, gfp);
-
+ in = fa_alloc(elem_size, incnt, gfp);
if (!in)
return -ENOMEM;
if (stream->in) {
- memcpy(in, stream->in, min(incnt, stream->incnt) *
- elem_size);
- kfree(stream->in);
+ fa_copy(in, stream->in, 0, min(incnt, stream->incnt));
+ fa_free(stream->in);
}
if (incnt > stream->incnt)
- memset(((struct sctp_stream_in *)in) + stream->incnt, 0,
- (incnt - stream->incnt) * elem_size);
+ fa_zero(in, stream->incnt, (incnt - stream->incnt));
stream->in = in;
@@ -188,7 +230,7 @@ int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
ret = sctp_stream_alloc_in(stream, incnt, gfp);
if (ret) {
sched->free(stream);
- kfree(stream->out);
+ fa_free(stream->out);
stream->out = NULL;
stream->outcnt = 0;
goto out;
@@ -220,8 +262,8 @@ void sctp_stream_free(struct sctp_stream *stream)
sched->free(stream);
for (i = 0; i < stream->outcnt; i++)
kfree(SCTP_SO(stream, i)->ext);
- kfree(stream->out);
- kfree(stream->in);
+ fa_free(stream->out);
+ fa_free(stream->in);
}
void sctp_stream_clear(struct sctp_stream *stream)
--
2.15.1
--
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