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Message-Id: <1702214654-32069-14-git-send-email-guwen@linux.alibaba.com>
Date: Sun, 10 Dec 2023 21:24:14 +0800
From: Wen Gu <guwen@...ux.alibaba.com>
To: wintera@...ux.ibm.com, wenjia@...ux.ibm.com, hca@...ux.ibm.com,
gor@...ux.ibm.com, agordeev@...ux.ibm.com, davem@...emloft.net,
edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
kgraul@...ux.ibm.com, jaka@...ux.ibm.com
Cc: borntraeger@...ux.ibm.com, svens@...ux.ibm.com,
alibuda@...ux.alibaba.com, tonylu@...ux.alibaba.com,
guwen@...ux.alibaba.com, linux-s390@...r.kernel.org,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH net-next 13/13] net/smc: implement {at|de}tach_dmb interfaces of loopback-ism
This implements attach_dmb and detach_dmb interfaces of loopback-ism.
The DMB won't be unregistered by loopback-ism until no sndbuf is
attached to it.
Signed-off-by: Wen Gu <guwen@...ux.alibaba.com>
---
net/smc/smc_loopback.c | 107 +++++++++++++++++++++++++++++++++++++++++++------
net/smc/smc_loopback.h | 4 ++
2 files changed, 99 insertions(+), 12 deletions(-)
diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
index 057ea6a..909c069 100644
--- a/net/smc/smc_loopback.c
+++ b/net/smc/smc_loopback.c
@@ -198,6 +198,7 @@ static int smc_lo_register_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb,
}
dmb_node->len = dmb->dmb_len;
dmb_node->dma_addr = SMC_DMA_ADDR_INVALID;
+ refcount_set(&dmb_node->refcnt, 1);
again:
/* add new dmb into hash table */
@@ -211,6 +212,7 @@ static int smc_lo_register_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb,
}
hash_add(ldev->dmb_ht, &dmb_node->list, dmb_node->token);
write_unlock(&ldev->dmb_ht_lock);
+ atomic_inc(&ldev->dmb_cnt);
SMC_LO_STAT_DMBS_INC(ldev);
dmb->sba_idx = dmb_node->sba_idx;
@@ -233,8 +235,8 @@ static int smc_lo_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
struct smc_lo_dev *ldev = smcd->priv;
- /* remove dmb from hash table */
- write_lock(&ldev->dmb_ht_lock);
+ /* find dmb from hash table */
+ read_lock(&ldev->dmb_ht_lock);
hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {
if (tmp_node->token == dmb->dmb_tok) {
dmb_node = tmp_node;
@@ -242,9 +244,18 @@ static int smc_lo_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
}
}
if (!dmb_node) {
- write_unlock(&ldev->dmb_ht_lock);
+ read_unlock(&ldev->dmb_ht_lock);
return -EINVAL;
}
+ read_unlock(&ldev->dmb_ht_lock);
+
+ /* wait for peer sndbuf to detach from this dmb */
+ if (!refcount_dec_and_test(&dmb_node->refcnt))
+ wait_event(ldev->dmbs_release,
+ !refcount_read(&dmb_node->refcnt));
+
+ /* remove dmb from hash table */
+ write_lock(&ldev->dmb_ht_lock);
hash_del(&dmb_node->list);
write_unlock(&ldev->dmb_ht_lock);
@@ -253,6 +264,66 @@ static int smc_lo_unregister_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
kfree(dmb_node);
SMC_LO_STAT_DMBS_DEC(ldev);
+ if (atomic_dec_and_test(&ldev->dmb_cnt))
+ wake_up(&ldev->ldev_release);
+ return 0;
+}
+
+static int smc_lo_attach_dmb(struct smcd_dev *smcd, struct smcd_dmb *dmb)
+{
+ struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
+ struct smc_lo_dev *ldev = smcd->priv;
+
+ /* find dmb_node according to dmb->dmb_tok */
+ read_lock(&ldev->dmb_ht_lock);
+ hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb->dmb_tok) {
+ if (tmp_node->token == dmb->dmb_tok) {
+ dmb_node = tmp_node;
+ break;
+ }
+ }
+ if (!dmb_node) {
+ read_unlock(&ldev->dmb_ht_lock);
+ return -EINVAL;
+ }
+ read_unlock(&ldev->dmb_ht_lock);
+
+ if (!refcount_inc_not_zero(&dmb_node->refcnt))
+ /* the dmb is being unregistered, but has
+ * not been removed from the hash table.
+ */
+ return -EINVAL;
+
+ /* provide dmb information */
+ dmb->sba_idx = dmb_node->sba_idx;
+ dmb->dmb_tok = dmb_node->token;
+ dmb->cpu_addr = dmb_node->cpu_addr;
+ dmb->dma_addr = dmb_node->dma_addr;
+ dmb->dmb_len = dmb_node->len;
+ return 0;
+}
+
+static int smc_lo_detach_dmb(struct smcd_dev *smcd, u64 token)
+{
+ struct smc_lo_dmb_node *dmb_node = NULL, *tmp_node;
+ struct smc_lo_dev *ldev = smcd->priv;
+
+ /* find dmb_node according to dmb->dmb_tok */
+ read_lock(&ldev->dmb_ht_lock);
+ hash_for_each_possible(ldev->dmb_ht, tmp_node, list, token) {
+ if (tmp_node->token == token) {
+ dmb_node = tmp_node;
+ break;
+ }
+ }
+ if (!dmb_node) {
+ read_unlock(&ldev->dmb_ht_lock);
+ return -EINVAL;
+ }
+ read_unlock(&ldev->dmb_ht_lock);
+
+ if (refcount_dec_and_test(&dmb_node->refcnt))
+ wake_up_all(&ldev->dmbs_release);
return 0;
}
@@ -288,7 +359,15 @@ static int smc_lo_move_data(struct smcd_dev *smcd, u64 dmb_tok,
{
struct smc_lo_dmb_node *rmb_node = NULL, *tmp_node;
struct smc_lo_dev *ldev = smcd->priv;
-
+ struct smc_connection *conn;
+
+ if (!sf) {
+ /* Since ghost sndbuf shares the same memory region
+ * with peer DMB, there is no need to 'transfer' data
+ * from sndbuf to peer DMB.
+ */
+ return 0;
+ }
read_lock(&ldev->dmb_ht_lock);
hash_for_each_possible(ldev->dmb_ht, tmp_node, list, dmb_tok) {
if (tmp_node->token == dmb_tok) {
@@ -305,14 +384,10 @@ static int smc_lo_move_data(struct smcd_dev *smcd, u64 dmb_tok,
memcpy((char *)rmb_node->cpu_addr + offset, data, size);
SMC_LO_STAT_TX_BYTES(ldev, size);
- if (sf) {
- struct smc_connection *conn =
- smcd->conn[rmb_node->sba_idx];
-
- if (conn && !conn->killed) {
- SMC_LO_STAT_RX_BYTES(ldev, size);
- smcd_cdc_rx_handler(conn);
- }
+ conn = smcd->conn[rmb_node->sba_idx];
+ if (conn && !conn->killed) {
+ SMC_LO_STAT_RX_BYTES(ldev, size);
+ smcd_cdc_rx_handler(conn);
}
return 0;
}
@@ -345,6 +420,8 @@ static struct device *smc_lo_get_dev(struct smcd_dev *smcd)
.query_remote_gid = smc_lo_query_rgid,
.register_dmb = smc_lo_register_dmb,
.unregister_dmb = smc_lo_unregister_dmb,
+ .attach_dmb = smc_lo_attach_dmb,
+ .detach_dmb = smc_lo_detach_dmb,
.add_vlan_id = smc_lo_add_vlan_id,
.del_vlan_id = smc_lo_del_vlan_id,
.set_vlan_required = smc_lo_set_vlan_required,
@@ -426,12 +503,18 @@ static int smc_lo_dev_init(struct smc_lo_dev *ldev)
smc_lo_generate_id(ldev);
rwlock_init(&ldev->dmb_ht_lock);
hash_init(ldev->dmb_ht);
+ atomic_set(&ldev->dmb_cnt, 0);
+ init_waitqueue_head(&ldev->dmbs_release);
+ init_waitqueue_head(&ldev->ldev_release);
+
return smcd_lo_register_dev(ldev);
}
static void smc_lo_dev_exit(struct smc_lo_dev *ldev)
{
smcd_lo_unregister_dev(ldev);
+ if (atomic_read(&ldev->dmb_cnt))
+ wait_event(ldev->ldev_release, !atomic_read(&ldev->dmb_cnt));
}
static void smc_lo_dev_release(struct device *dev)
diff --git a/net/smc/smc_loopback.h b/net/smc/smc_loopback.h
index ad0feaa..df6c252 100644
--- a/net/smc/smc_loopback.h
+++ b/net/smc/smc_loopback.h
@@ -30,6 +30,7 @@ struct smc_lo_dmb_node {
u32 sba_idx;
void *cpu_addr;
dma_addr_t dma_addr;
+ refcount_t refcnt;
};
struct smc_lo_dev_stats64 {
@@ -45,9 +46,12 @@ struct smc_lo_dev {
u16 chid;
struct smcd_gid local_gid;
struct smc_lo_dev_stats64 __percpu *stats;
+ atomic_t dmb_cnt;
rwlock_t dmb_ht_lock;
DECLARE_BITMAP(sba_idx_mask, SMC_LO_MAX_DMBS);
DECLARE_HASHTABLE(dmb_ht, SMC_LO_DMBS_HASH_BITS);
+ wait_queue_head_t dmbs_release;
+ wait_queue_head_t ldev_release;
};
#define SMC_LO_STAT_SUB(ldev, key, val) \
--
1.8.3.1
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