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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@virtuozzo.com>
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Konstantin Khorenko 2018-08-10 20:11:43 +03:00 committed by David S. Miller
parent 05364ca03c
commit 0d493b4d0b
2 changed files with 71 additions and 26 deletions
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9
include/net/sctp/structs.h
View File

@ -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 */
@ -1438,8 +1439,8 @@ 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 */
@ -1465,14 +1466,14 @@ 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))

88
net/sctp/stream.c
View File

@ -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 @@ in:
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)