[PATCH net-next 15/15] net/smc: implement DMB-merged operations of loopback-ism
From: Wen Gu
Date: Thu Jan 11 2024 - 07:05:48 EST
This implements operations related to merging sndbuf with peer DMB in
loopback-ism. The DMB won't be unregistered until no sndbuf is attached
to it.
Signed-off-by: Wen Gu <guwen@xxxxxxxxxxxxxxxxx>
---
net/smc/smc_loopback.c | 101 +++++++++++++++++++++++++++++++++++++++--
net/smc/smc_loopback.h | 4 ++
2 files changed, 102 insertions(+), 3 deletions(-)
diff --git a/net/smc/smc_loopback.c b/net/smc/smc_loopback.c
index bfbb346ef01a..296a4d1f1a33 100644
--- a/net/smc/smc_loopback.c
+++ b/net/smc/smc_loopback.c
@@ -298,6 +298,7 @@ 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 */
@@ -311,6 +312,7 @@ 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;
@@ -333,8 +335,8 @@ 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;
@@ -342,9 +344,18 @@ 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);
@@ -353,6 +364,73 @@ 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_support_dmb_nocopy(struct smcd_dev *smcd)
+{
+ struct smc_lo_dev *ldev = smcd->priv;
+
+ return (ldev->dmb_copy == SMC_LO_DMB_NOCOPY);
+}
+
+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;
}
@@ -389,6 +467,14 @@ 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;
+ /* if sndbuf is merged with peer DMB, there is
+ * no need to copy data from sndbuf to peer DMB.
+ */
+ if (!sf && smc_lo_support_dmb_nocopy(smcd)) {
+ SMC_LO_STAT_XFER_BYTES(ldev, size);
+ 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) {
@@ -444,6 +530,9 @@ static const struct smcd_ops lo_ops = {
.query_remote_gid = smc_lo_query_rgid,
.register_dmb = smc_lo_register_dmb,
.unregister_dmb = smc_lo_unregister_dmb,
+ .support_dmb_nocopy = smc_lo_support_dmb_nocopy,
+ .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,
@@ -529,12 +618,18 @@ 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 7ecb4a35eb36..19a1eace2255 100644
--- a/net/smc/smc_loopback.h
+++ b/net/smc/smc_loopback.h
@@ -40,6 +40,7 @@ struct smc_lo_dmb_node {
u32 sba_idx;
void *cpu_addr;
dma_addr_t dma_addr;
+ refcount_t refcnt;
};
struct smc_lo_dev_stats64 {
@@ -56,9 +57,12 @@ 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) \
--
2.32.0.3.g01195cf9f