linux/net/rds/ib_rdma.c
Gerd Rausch c9467447fc net/rds: Get rid of "wait_clean_list_grace" and add locking
Waiting for activity on the "clean_list" to quiesce is no substitute
for proper locking.

We can have multiple threads competing for "llist_del_first"
via "rds_ib_reuse_mr", and a single thread competing
for "llist_del_all" and "llist_del_first" via "rds_ib_flush_mr_pool".

Since "llist_del_first" depends on "list->first->next" not to change
in the midst of the operation, simply waiting for all current calls
to "rds_ib_reuse_mr" to quiesce across all CPUs is woefully inadequate:

By the time "wait_clean_list_grace" is done iterating over all CPUs to see
that there is no concurrent caller to "rds_ib_reuse_mr", a new caller may
have just shown up on the first CPU.

Furthermore, <linux/llist.h> explicitly calls out the need for locking:
 * Cases where locking is needed:
 * If we have multiple consumers with llist_del_first used in one consumer,
 * and llist_del_first or llist_del_all used in other consumers,
 * then a lock is needed.

Also, while at it, drop the unused "pool" parameter
from "list_to_llist_nodes".

Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-17 12:06:51 -07:00

632 lines
16 KiB
C

/*
* Copyright (c) 2006, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/rculist.h>
#include <linux/llist.h>
#include "rds_single_path.h"
#include "ib_mr.h"
struct workqueue_struct *rds_ib_mr_wq;
static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr)
{
struct rds_ib_device *rds_ibdev;
struct rds_ib_ipaddr *i_ipaddr;
rcu_read_lock();
list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) {
list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
if (i_ipaddr->ipaddr == ipaddr) {
refcount_inc(&rds_ibdev->refcount);
rcu_read_unlock();
return rds_ibdev;
}
}
}
rcu_read_unlock();
return NULL;
}
static int rds_ib_add_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
{
struct rds_ib_ipaddr *i_ipaddr;
i_ipaddr = kmalloc(sizeof *i_ipaddr, GFP_KERNEL);
if (!i_ipaddr)
return -ENOMEM;
i_ipaddr->ipaddr = ipaddr;
spin_lock_irq(&rds_ibdev->spinlock);
list_add_tail_rcu(&i_ipaddr->list, &rds_ibdev->ipaddr_list);
spin_unlock_irq(&rds_ibdev->spinlock);
return 0;
}
static void rds_ib_remove_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr)
{
struct rds_ib_ipaddr *i_ipaddr;
struct rds_ib_ipaddr *to_free = NULL;
spin_lock_irq(&rds_ibdev->spinlock);
list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) {
if (i_ipaddr->ipaddr == ipaddr) {
list_del_rcu(&i_ipaddr->list);
to_free = i_ipaddr;
break;
}
}
spin_unlock_irq(&rds_ibdev->spinlock);
if (to_free)
kfree_rcu(to_free, rcu);
}
int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev,
struct in6_addr *ipaddr)
{
struct rds_ib_device *rds_ibdev_old;
rds_ibdev_old = rds_ib_get_device(ipaddr->s6_addr32[3]);
if (!rds_ibdev_old)
return rds_ib_add_ipaddr(rds_ibdev, ipaddr->s6_addr32[3]);
if (rds_ibdev_old != rds_ibdev) {
rds_ib_remove_ipaddr(rds_ibdev_old, ipaddr->s6_addr32[3]);
rds_ib_dev_put(rds_ibdev_old);
return rds_ib_add_ipaddr(rds_ibdev, ipaddr->s6_addr32[3]);
}
rds_ib_dev_put(rds_ibdev_old);
return 0;
}
void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
{
struct rds_ib_connection *ic = conn->c_transport_data;
/* conn was previously on the nodev_conns_list */
spin_lock_irq(&ib_nodev_conns_lock);
BUG_ON(list_empty(&ib_nodev_conns));
BUG_ON(list_empty(&ic->ib_node));
list_del(&ic->ib_node);
spin_lock(&rds_ibdev->spinlock);
list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);
spin_unlock(&rds_ibdev->spinlock);
spin_unlock_irq(&ib_nodev_conns_lock);
ic->rds_ibdev = rds_ibdev;
refcount_inc(&rds_ibdev->refcount);
}
void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)
{
struct rds_ib_connection *ic = conn->c_transport_data;
/* place conn on nodev_conns_list */
spin_lock(&ib_nodev_conns_lock);
spin_lock_irq(&rds_ibdev->spinlock);
BUG_ON(list_empty(&ic->ib_node));
list_del(&ic->ib_node);
spin_unlock_irq(&rds_ibdev->spinlock);
list_add_tail(&ic->ib_node, &ib_nodev_conns);
spin_unlock(&ib_nodev_conns_lock);
ic->rds_ibdev = NULL;
rds_ib_dev_put(rds_ibdev);
}
void rds_ib_destroy_nodev_conns(void)
{
struct rds_ib_connection *ic, *_ic;
LIST_HEAD(tmp_list);
/* avoid calling conn_destroy with irqs off */
spin_lock_irq(&ib_nodev_conns_lock);
list_splice(&ib_nodev_conns, &tmp_list);
spin_unlock_irq(&ib_nodev_conns_lock);
list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node)
rds_conn_destroy(ic->conn);
}
void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo)
{
struct rds_ib_mr_pool *pool_1m = rds_ibdev->mr_1m_pool;
iinfo->rdma_mr_max = pool_1m->max_items;
iinfo->rdma_mr_size = pool_1m->fmr_attr.max_pages;
}
#if IS_ENABLED(CONFIG_IPV6)
void rds6_ib_get_mr_info(struct rds_ib_device *rds_ibdev,
struct rds6_info_rdma_connection *iinfo6)
{
struct rds_ib_mr_pool *pool_1m = rds_ibdev->mr_1m_pool;
iinfo6->rdma_mr_max = pool_1m->max_items;
iinfo6->rdma_mr_size = pool_1m->fmr_attr.max_pages;
}
#endif
struct rds_ib_mr *rds_ib_reuse_mr(struct rds_ib_mr_pool *pool)
{
struct rds_ib_mr *ibmr = NULL;
struct llist_node *ret;
unsigned long flags;
spin_lock_irqsave(&pool->clean_lock, flags);
ret = llist_del_first(&pool->clean_list);
spin_unlock_irqrestore(&pool->clean_lock, flags);
if (ret) {
ibmr = llist_entry(ret, struct rds_ib_mr, llnode);
if (pool->pool_type == RDS_IB_MR_8K_POOL)
rds_ib_stats_inc(s_ib_rdma_mr_8k_reused);
else
rds_ib_stats_inc(s_ib_rdma_mr_1m_reused);
}
return ibmr;
}
void rds_ib_sync_mr(void *trans_private, int direction)
{
struct rds_ib_mr *ibmr = trans_private;
struct rds_ib_device *rds_ibdev = ibmr->device;
switch (direction) {
case DMA_FROM_DEVICE:
ib_dma_sync_sg_for_cpu(rds_ibdev->dev, ibmr->sg,
ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
break;
case DMA_TO_DEVICE:
ib_dma_sync_sg_for_device(rds_ibdev->dev, ibmr->sg,
ibmr->sg_dma_len, DMA_BIDIRECTIONAL);
break;
}
}
void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
{
struct rds_ib_device *rds_ibdev = ibmr->device;
if (ibmr->sg_dma_len) {
ib_dma_unmap_sg(rds_ibdev->dev,
ibmr->sg, ibmr->sg_len,
DMA_BIDIRECTIONAL);
ibmr->sg_dma_len = 0;
}
/* Release the s/g list */
if (ibmr->sg_len) {
unsigned int i;
for (i = 0; i < ibmr->sg_len; ++i) {
struct page *page = sg_page(&ibmr->sg[i]);
/* FIXME we need a way to tell a r/w MR
* from a r/o MR */
WARN_ON(!page->mapping && irqs_disabled());
set_page_dirty(page);
put_page(page);
}
kfree(ibmr->sg);
ibmr->sg = NULL;
ibmr->sg_len = 0;
}
}
void rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
{
unsigned int pinned = ibmr->sg_len;
__rds_ib_teardown_mr(ibmr);
if (pinned) {
struct rds_ib_mr_pool *pool = ibmr->pool;
atomic_sub(pinned, &pool->free_pinned);
}
}
static inline unsigned int rds_ib_flush_goal(struct rds_ib_mr_pool *pool, int free_all)
{
unsigned int item_count;
item_count = atomic_read(&pool->item_count);
if (free_all)
return item_count;
return 0;
}
/*
* given an llist of mrs, put them all into the list_head for more processing
*/
static unsigned int llist_append_to_list(struct llist_head *llist,
struct list_head *list)
{
struct rds_ib_mr *ibmr;
struct llist_node *node;
struct llist_node *next;
unsigned int count = 0;
node = llist_del_all(llist);
while (node) {
next = node->next;
ibmr = llist_entry(node, struct rds_ib_mr, llnode);
list_add_tail(&ibmr->unmap_list, list);
node = next;
count++;
}
return count;
}
/*
* this takes a list head of mrs and turns it into linked llist nodes
* of clusters. Each cluster has linked llist nodes of
* MR_CLUSTER_SIZE mrs that are ready for reuse.
*/
static void list_to_llist_nodes(struct list_head *list,
struct llist_node **nodes_head,
struct llist_node **nodes_tail)
{
struct rds_ib_mr *ibmr;
struct llist_node *cur = NULL;
struct llist_node **next = nodes_head;
list_for_each_entry(ibmr, list, unmap_list) {
cur = &ibmr->llnode;
*next = cur;
next = &cur->next;
}
*next = NULL;
*nodes_tail = cur;
}
/*
* Flush our pool of MRs.
* At a minimum, all currently unused MRs are unmapped.
* If the number of MRs allocated exceeds the limit, we also try
* to free as many MRs as needed to get back to this limit.
*/
int rds_ib_flush_mr_pool(struct rds_ib_mr_pool *pool,
int free_all, struct rds_ib_mr **ibmr_ret)
{
struct rds_ib_mr *ibmr;
struct llist_node *clean_nodes;
struct llist_node *clean_tail;
LIST_HEAD(unmap_list);
unsigned long unpinned = 0;
unsigned int nfreed = 0, dirty_to_clean = 0, free_goal;
if (pool->pool_type == RDS_IB_MR_8K_POOL)
rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_flush);
else
rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_flush);
if (ibmr_ret) {
DEFINE_WAIT(wait);
while (!mutex_trylock(&pool->flush_lock)) {
ibmr = rds_ib_reuse_mr(pool);
if (ibmr) {
*ibmr_ret = ibmr;
finish_wait(&pool->flush_wait, &wait);
goto out_nolock;
}
prepare_to_wait(&pool->flush_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (llist_empty(&pool->clean_list))
schedule();
ibmr = rds_ib_reuse_mr(pool);
if (ibmr) {
*ibmr_ret = ibmr;
finish_wait(&pool->flush_wait, &wait);
goto out_nolock;
}
}
finish_wait(&pool->flush_wait, &wait);
} else
mutex_lock(&pool->flush_lock);
if (ibmr_ret) {
ibmr = rds_ib_reuse_mr(pool);
if (ibmr) {
*ibmr_ret = ibmr;
goto out;
}
}
/* Get the list of all MRs to be dropped. Ordering matters -
* we want to put drop_list ahead of free_list.
*/
dirty_to_clean = llist_append_to_list(&pool->drop_list, &unmap_list);
dirty_to_clean += llist_append_to_list(&pool->free_list, &unmap_list);
if (free_all) {
unsigned long flags;
spin_lock_irqsave(&pool->clean_lock, flags);
llist_append_to_list(&pool->clean_list, &unmap_list);
spin_unlock_irqrestore(&pool->clean_lock, flags);
}
free_goal = rds_ib_flush_goal(pool, free_all);
if (list_empty(&unmap_list))
goto out;
if (pool->use_fastreg)
rds_ib_unreg_frmr(&unmap_list, &nfreed, &unpinned, free_goal);
else
rds_ib_unreg_fmr(&unmap_list, &nfreed, &unpinned, free_goal);
if (!list_empty(&unmap_list)) {
unsigned long flags;
list_to_llist_nodes(&unmap_list, &clean_nodes, &clean_tail);
if (ibmr_ret) {
*ibmr_ret = llist_entry(clean_nodes, struct rds_ib_mr, llnode);
clean_nodes = clean_nodes->next;
}
/* more than one entry in llist nodes */
if (clean_nodes) {
spin_lock_irqsave(&pool->clean_lock, flags);
llist_add_batch(clean_nodes, clean_tail,
&pool->clean_list);
spin_unlock_irqrestore(&pool->clean_lock, flags);
}
}
atomic_sub(unpinned, &pool->free_pinned);
atomic_sub(dirty_to_clean, &pool->dirty_count);
atomic_sub(nfreed, &pool->item_count);
out:
mutex_unlock(&pool->flush_lock);
if (waitqueue_active(&pool->flush_wait))
wake_up(&pool->flush_wait);
out_nolock:
return 0;
}
struct rds_ib_mr *rds_ib_try_reuse_ibmr(struct rds_ib_mr_pool *pool)
{
struct rds_ib_mr *ibmr = NULL;
int iter = 0;
while (1) {
ibmr = rds_ib_reuse_mr(pool);
if (ibmr)
return ibmr;
if (atomic_inc_return(&pool->item_count) <= pool->max_items)
break;
atomic_dec(&pool->item_count);
if (++iter > 2) {
if (pool->pool_type == RDS_IB_MR_8K_POOL)
rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_depleted);
else
rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_depleted);
return ERR_PTR(-EAGAIN);
}
/* We do have some empty MRs. Flush them out. */
if (pool->pool_type == RDS_IB_MR_8K_POOL)
rds_ib_stats_inc(s_ib_rdma_mr_8k_pool_wait);
else
rds_ib_stats_inc(s_ib_rdma_mr_1m_pool_wait);
rds_ib_flush_mr_pool(pool, 0, &ibmr);
if (ibmr)
return ibmr;
}
return ibmr;
}
static void rds_ib_mr_pool_flush_worker(struct work_struct *work)
{
struct rds_ib_mr_pool *pool = container_of(work, struct rds_ib_mr_pool, flush_worker.work);
rds_ib_flush_mr_pool(pool, 0, NULL);
}
void rds_ib_free_mr(void *trans_private, int invalidate)
{
struct rds_ib_mr *ibmr = trans_private;
struct rds_ib_mr_pool *pool = ibmr->pool;
struct rds_ib_device *rds_ibdev = ibmr->device;
rdsdebug("RDS/IB: free_mr nents %u\n", ibmr->sg_len);
/* Return it to the pool's free list */
if (rds_ibdev->use_fastreg)
rds_ib_free_frmr_list(ibmr);
else
rds_ib_free_fmr_list(ibmr);
atomic_add(ibmr->sg_len, &pool->free_pinned);
atomic_inc(&pool->dirty_count);
/* If we've pinned too many pages, request a flush */
if (atomic_read(&pool->free_pinned) >= pool->max_free_pinned ||
atomic_read(&pool->dirty_count) >= pool->max_items / 5)
queue_delayed_work(rds_ib_mr_wq, &pool->flush_worker, 10);
if (invalidate) {
if (likely(!in_interrupt())) {
rds_ib_flush_mr_pool(pool, 0, NULL);
} else {
/* We get here if the user created a MR marked
* as use_once and invalidate at the same time.
*/
queue_delayed_work(rds_ib_mr_wq,
&pool->flush_worker, 10);
}
}
rds_ib_dev_put(rds_ibdev);
}
void rds_ib_flush_mrs(void)
{
struct rds_ib_device *rds_ibdev;
down_read(&rds_ib_devices_lock);
list_for_each_entry(rds_ibdev, &rds_ib_devices, list) {
if (rds_ibdev->mr_8k_pool)
rds_ib_flush_mr_pool(rds_ibdev->mr_8k_pool, 0, NULL);
if (rds_ibdev->mr_1m_pool)
rds_ib_flush_mr_pool(rds_ibdev->mr_1m_pool, 0, NULL);
}
up_read(&rds_ib_devices_lock);
}
void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
struct rds_sock *rs, u32 *key_ret,
struct rds_connection *conn)
{
struct rds_ib_device *rds_ibdev;
struct rds_ib_mr *ibmr = NULL;
struct rds_ib_connection *ic = NULL;
int ret;
rds_ibdev = rds_ib_get_device(rs->rs_bound_addr.s6_addr32[3]);
if (!rds_ibdev) {
ret = -ENODEV;
goto out;
}
if (conn)
ic = conn->c_transport_data;
if (!rds_ibdev->mr_8k_pool || !rds_ibdev->mr_1m_pool) {
ret = -ENODEV;
goto out;
}
if (rds_ibdev->use_fastreg)
ibmr = rds_ib_reg_frmr(rds_ibdev, ic, sg, nents, key_ret);
else
ibmr = rds_ib_reg_fmr(rds_ibdev, sg, nents, key_ret);
if (IS_ERR(ibmr)) {
ret = PTR_ERR(ibmr);
pr_warn("RDS/IB: rds_ib_get_mr failed (errno=%d)\n", ret);
} else {
return ibmr;
}
out:
if (rds_ibdev)
rds_ib_dev_put(rds_ibdev);
return ERR_PTR(ret);
}
void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *pool)
{
cancel_delayed_work_sync(&pool->flush_worker);
rds_ib_flush_mr_pool(pool, 1, NULL);
WARN_ON(atomic_read(&pool->item_count));
WARN_ON(atomic_read(&pool->free_pinned));
kfree(pool);
}
struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *rds_ibdev,
int pool_type)
{
struct rds_ib_mr_pool *pool;
pool = kzalloc(sizeof(*pool), GFP_KERNEL);
if (!pool)
return ERR_PTR(-ENOMEM);
pool->pool_type = pool_type;
init_llist_head(&pool->free_list);
init_llist_head(&pool->drop_list);
init_llist_head(&pool->clean_list);
spin_lock_init(&pool->clean_lock);
mutex_init(&pool->flush_lock);
init_waitqueue_head(&pool->flush_wait);
INIT_DELAYED_WORK(&pool->flush_worker, rds_ib_mr_pool_flush_worker);
if (pool_type == RDS_IB_MR_1M_POOL) {
/* +1 allows for unaligned MRs */
pool->fmr_attr.max_pages = RDS_MR_1M_MSG_SIZE + 1;
pool->max_items = rds_ibdev->max_1m_mrs;
} else {
/* pool_type == RDS_IB_MR_8K_POOL */
pool->fmr_attr.max_pages = RDS_MR_8K_MSG_SIZE + 1;
pool->max_items = rds_ibdev->max_8k_mrs;
}
pool->max_free_pinned = pool->max_items * pool->fmr_attr.max_pages / 4;
pool->fmr_attr.max_maps = rds_ibdev->fmr_max_remaps;
pool->fmr_attr.page_shift = PAGE_SHIFT;
pool->max_items_soft = rds_ibdev->max_mrs * 3 / 4;
pool->use_fastreg = rds_ibdev->use_fastreg;
return pool;
}
int rds_ib_mr_init(void)
{
rds_ib_mr_wq = alloc_workqueue("rds_mr_flushd", WQ_MEM_RECLAIM, 0);
if (!rds_ib_mr_wq)
return -ENOMEM;
return 0;
}
/* By the time this is called all the IB devices should have been torn down and
* had their pools freed. As each pool is freed its work struct is waited on,
* so the pool flushing work queue should be idle by the time we get here.
*/
void rds_ib_mr_exit(void)
{
destroy_workqueue(rds_ib_mr_wq);
}