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Message-Id: <20180810171143.21592-3-khorenko@virtuozzo.com>
Date: Fri, 10 Aug 2018 20:11:43 +0300
From: Konstantin Khorenko <khorenko@...tuozzo.com>
To: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Cc: oleg.babin@...il.com, netdev@...r.kernel.org,
linux-sctp@...r.kernel.org,
"David S . Miller" <davem@...emloft.net>,
Vlad Yasevich <vyasevich@...il.com>,
Neil Horman <nhorman@...driver.com>,
Xin Long <lucien.xin@...il.com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Konstantin Khorenko <khorenko@...tuozzo.com>
Subject: [PATCH v3 2/2] net/sctp: Replace in/out stream arrays with flex_array
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@...tuozzo.com>
Signed-off-by: Konstantin Khorenko <khorenko@...tuozzo.com>
---
include/net/sctp/structs.h | 9 ++---
net/sctp/stream.c | 88 ++++++++++++++++++++++++++++++++++------------
2 files changed, 71 insertions(+), 26 deletions(-)
diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h
index ce4bf844f573..f922db8029e6 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 */
@@ -1431,8 +1432,8 @@ struct sctp_stream_in {
};
struct sctp_stream {
- struct sctp_stream_out *out;
- struct sctp_stream_in *in;
+ struct flex_array *out;
+ struct flex_array *in;
__u16 outcnt;
__u16 incnt;
/* Current stream being sent, if any */
@@ -1458,14 +1459,14 @@ static inline 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);
}
static inline 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);
}
#define SCTP_SO(s, i) sctp_stream_out((s), (i))
diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index 7ca6fe4e7882..ffb940d3b57c 100644
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -37,6 +37,53 @@
#include <net/sctp/sm.h>
#include <net/sctp/stream_sched.h>
+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,
* but not across associations. Also, removes those chunks to streams
* higher than the new max.
@@ -78,34 +125,33 @@ static void sctp_stream_outq_migrate(struct sctp_stream *stream,
* sctp_stream_update will swap ->out pointers.
*/
for (i = 0; i < outcnt; i++) {
- kfree(new->out[i].ext);
- new->out[i].ext = stream->out[i].ext;
- stream->out[i].ext = NULL;
+ kfree(SCTP_SO(new, i)->ext);
+ SCTP_SO(new, i)->ext = SCTP_SO(stream, i)->ext;
+ SCTP_SO(stream, i)->ext = NULL;
}
}
for (i = outcnt; i < stream->outcnt; i++)
- kfree(stream->out[i].ext);
+ kfree(SCTP_SO(stream, i)->ext);
}
static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
gfp_t gfp)
{
- struct sctp_stream_out *out;
+ struct flex_array *out;
+ size_t elem_size = sizeof(struct sctp_stream_out);
- out = kmalloc_array(outcnt, sizeof(*out), gfp);
+ out = fa_alloc(elem_size, outcnt, gfp);
if (!out)
return -ENOMEM;
if (stream->out) {
- memcpy(out, stream->out, min(outcnt, stream->outcnt) *
- sizeof(*out));
- kfree(stream->out);
+ fa_copy(out, stream->out, 0, min(outcnt, stream->outcnt));
+ fa_free(stream->out);
}
if (outcnt > stream->outcnt)
- memset(out + stream->outcnt, 0,
- (outcnt - stream->outcnt) * sizeof(*out));
+ fa_zero(out, stream->outcnt, (outcnt - stream->outcnt));
stream->out = out;
@@ -115,22 +161,20 @@ static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
static int sctp_stream_alloc_in(struct sctp_stream *stream, __u16 incnt,
gfp_t gfp)
{
- struct sctp_stream_in *in;
-
- in = kmalloc_array(incnt, sizeof(*stream->in), gfp);
+ struct flex_array *in;
+ size_t elem_size = sizeof(struct sctp_stream_in);
+ in = fa_alloc(elem_size, incnt, gfp);
if (!in)
return -ENOMEM;
if (stream->in) {
- memcpy(in, stream->in, min(incnt, stream->incnt) *
- sizeof(*in));
- kfree(stream->in);
+ fa_copy(in, stream->in, 0, min(incnt, stream->incnt));
+ fa_free(stream->in);
}
if (incnt > stream->incnt)
- memset(in + stream->incnt, 0,
- (incnt - stream->incnt) * sizeof(*in));
+ fa_zero(in, stream->incnt, (incnt - stream->incnt));
stream->in = in;
@@ -174,7 +218,7 @@ 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;
@@ -206,8 +250,8 @@ 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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