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linux-next/net/ceph/msgpool.c
Ilya Dryomov 0d9c1ab3be libceph: preallocate message data items
Currently message data items are allocated with ceph_msg_data_create()
in setup_request_data() inside send_request().  send_request() has never
been allowed to fail, so each allocation is followed by a BUG_ON:

  data = ceph_msg_data_create(...);
  BUG_ON(!data);

It's been this way since support for multiple message data items was
added in commit 6644ed7b7e ("libceph: make message data be a pointer")
in 3.10.

There is no reason to delay the allocation of message data items until
the last possible moment and we certainly don't need a linked list of
them as they are only ever appended to the end and never erased.  Make
ceph_msg_new2() take max_data_items and adapt the rest of the code.

Reported-by: Jerry Lee <leisurelysw24@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2018-10-22 10:28:22 +02:00

95 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/ceph/ceph_debug.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/ceph/messenger.h>
#include <linux/ceph/msgpool.h>
static void *msgpool_alloc(gfp_t gfp_mask, void *arg)
{
struct ceph_msgpool *pool = arg;
struct ceph_msg *msg;
msg = ceph_msg_new2(pool->type, pool->front_len, pool->max_data_items,
gfp_mask, true);
if (!msg) {
dout("msgpool_alloc %s failed\n", pool->name);
} else {
dout("msgpool_alloc %s %p\n", pool->name, msg);
msg->pool = pool;
}
return msg;
}
static void msgpool_free(void *element, void *arg)
{
struct ceph_msgpool *pool = arg;
struct ceph_msg *msg = element;
dout("msgpool_release %s %p\n", pool->name, msg);
msg->pool = NULL;
ceph_msg_put(msg);
}
int ceph_msgpool_init(struct ceph_msgpool *pool, int type,
int front_len, int max_data_items, int size,
const char *name)
{
dout("msgpool %s init\n", name);
pool->type = type;
pool->front_len = front_len;
pool->max_data_items = max_data_items;
pool->pool = mempool_create(size, msgpool_alloc, msgpool_free, pool);
if (!pool->pool)
return -ENOMEM;
pool->name = name;
return 0;
}
void ceph_msgpool_destroy(struct ceph_msgpool *pool)
{
dout("msgpool %s destroy\n", pool->name);
mempool_destroy(pool->pool);
}
struct ceph_msg *ceph_msgpool_get(struct ceph_msgpool *pool, int front_len,
int max_data_items)
{
struct ceph_msg *msg;
if (front_len > pool->front_len ||
max_data_items > pool->max_data_items) {
pr_warn_ratelimited("%s need %d/%d, pool %s has %d/%d\n",
__func__, front_len, max_data_items, pool->name,
pool->front_len, pool->max_data_items);
WARN_ON_ONCE(1);
/* try to alloc a fresh message */
return ceph_msg_new2(pool->type, front_len, max_data_items,
GFP_NOFS, false);
}
msg = mempool_alloc(pool->pool, GFP_NOFS);
dout("msgpool_get %s %p\n", pool->name, msg);
return msg;
}
void ceph_msgpool_put(struct ceph_msgpool *pool, struct ceph_msg *msg)
{
dout("msgpool_put %s %p\n", pool->name, msg);
/* reset msg front_len; user may have changed it */
msg->front.iov_len = pool->front_len;
msg->hdr.front_len = cpu_to_le32(pool->front_len);
msg->data_length = 0;
msg->num_data_items = 0;
kref_init(&msg->kref); /* retake single ref */
mempool_free(msg, pool->pool);
}