smb: server: manage recv credits by counting posted recv_io and granted credits

(At least for me) the logic maintaining the count of posted
recv_io messages and the count of granted credits is much
easier to understand.

From there we can easily calculate the number of new_credits we'll
grant to the peer in outgoing send_io messages.

This will simplify the move to common logic that can be
shared between client and server in the following patches.

Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Stefan Metzmacher
2025-08-14 16:05:47 +02:00
committed by Steve French
parent 113ed9d56f
commit 89b021a726

View File

@@ -92,13 +92,10 @@ struct smb_direct_transport {
struct smbdirect_socket socket;
spinlock_t receive_credit_lock;
int recv_credits;
atomic_t recv_credits;
u16 recv_credit_target;
spinlock_t lock_new_recv_credits;
int new_recv_credits;
atomic_t recv_posted;
struct work_struct post_recv_credits_work;
struct work_struct send_immediate_work;
@@ -309,9 +306,8 @@ static struct smb_direct_transport *alloc_transport(struct rdma_cm_id *cm_id)
sc->ib.dev = sc->rdma.cm_id->device;
spin_lock_init(&t->receive_credit_lock);
spin_lock_init(&t->lock_new_recv_credits);
atomic_set(&t->recv_posted, 0);
atomic_set(&t->recv_credits, 0);
INIT_WORK(&t->post_recv_credits_work,
smb_direct_post_recv_credits);
@@ -552,9 +548,8 @@ static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
sc->recv_io.reassembly.full_packet_received = true;
}
spin_lock(&t->receive_credit_lock);
t->recv_credits -= 1;
spin_unlock(&t->receive_credit_lock);
atomic_dec(&t->recv_posted);
atomic_dec(&t->recv_credits);
old_recv_credit_target = t->recv_credit_target;
t->recv_credit_target =
@@ -758,14 +753,10 @@ static void smb_direct_post_recv_credits(struct work_struct *work)
struct smb_direct_transport *t = container_of(work,
struct smb_direct_transport, post_recv_credits_work);
struct smbdirect_recv_io *recvmsg;
int receive_credits, credits = 0;
int credits = 0;
int ret;
spin_lock(&t->receive_credit_lock);
receive_credits = t->recv_credits;
spin_unlock(&t->receive_credit_lock);
if (receive_credits < t->recv_credit_target) {
if (atomic_read(&t->recv_credits) < t->recv_credit_target) {
while (true) {
recvmsg = get_free_recvmsg(t);
if (!recvmsg)
@@ -780,17 +771,11 @@ static void smb_direct_post_recv_credits(struct work_struct *work)
break;
}
credits++;
atomic_inc(&t->recv_posted);
}
}
spin_lock(&t->receive_credit_lock);
t->recv_credits += credits;
spin_unlock(&t->receive_credit_lock);
spin_lock(&t->lock_new_recv_credits);
t->new_recv_credits += credits;
spin_unlock(&t->lock_new_recv_credits);
if (credits)
queue_work(smb_direct_wq, &t->send_immediate_work);
}
@@ -837,11 +822,18 @@ static int manage_credits_prior_sending(struct smb_direct_transport *t)
{
int new_credits;
spin_lock(&t->lock_new_recv_credits);
new_credits = t->new_recv_credits;
t->new_recv_credits = 0;
spin_unlock(&t->lock_new_recv_credits);
if (atomic_read(&t->recv_credits) >= t->recv_credit_target)
return 0;
new_credits = atomic_read(&t->recv_posted);
if (new_credits == 0)
return 0;
new_credits -= atomic_read(&t->recv_credits);
if (new_credits <= 0)
return 0;
atomic_add(new_credits, &t->recv_credits);
return new_credits;
}
@@ -1824,11 +1816,8 @@ static int smb_direct_init_params(struct smb_direct_transport *t,
return -EINVAL;
}
t->recv_credits = 0;
sp->recv_credit_max = smb_direct_receive_credit_max;
t->recv_credit_target = 1;
t->new_recv_credits = 0;
sp->send_credit_target = smb_direct_send_credit_target;
atomic_set(&sc->rw_io.credits.count, sc->rw_io.credits.max);