[PATCH v3] ksmbd: fix outstanding credits related bugs

[Hyunchul Lee <hyc.lee@gmail.com>]

outstanding credits must be initialized to 0,
because it means the sum of credits consumed by
in-flight requests.
And outstanding credits must be compared with
total credits in smb2_validate_credit_charge(),
because total credits are the sum of credits
granted by ksmbd.

This patch fix the following error,
while frametest with Windows clients:

Limits exceeding the maximum allowable outstanding requests,
given : 128, pending : 8065

Fixes: b589f5db6d4a ("ksmbd: limits exceeding the maximum allowable outstanding requests")
Cc: stable@vger.kernel.org
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Reported-by: Yufan Chen <wiz.chen@gmail.com>
Tested-by: Yufan Chen <wiz.chen@gmail.com>
---
changes from v2:
 - fix underflow issue of outstanding credits while mutli-protocol negotiation
   with an Windows client
changes from v1:
 - Add "Fixes" and stable tags

 fs/ksmbd/connection.c | 2 +-
 fs/ksmbd/smb2misc.c   | 2 +-
 fs/ksmbd/smb_common.c | 4 +++-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c
index 7db87771884a..e8f476c5f189 100644
--- a/fs/ksmbd/connection.c
+++ b/fs/ksmbd/connection.c
@@ -62,7 +62,7 @@ struct ksmbd_conn *ksmbd_conn_alloc(void)
 	atomic_set(&conn->req_running, 0);
 	atomic_set(&conn->r_count, 0);
 	conn->total_credits = 1;
-	conn->outstanding_credits = 1;
+	conn->outstanding_credits = 0;
 
 	init_waitqueue_head(&conn->req_running_q);
 	INIT_LIST_HEAD(&conn->conns_list);
diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c
index 4a9460153b59..f8f456377a51 100644
--- a/fs/ksmbd/smb2misc.c
+++ b/fs/ksmbd/smb2misc.c
@@ -338,7 +338,7 @@ static int smb2_validate_credit_charge(struct ksmbd_conn *conn,
 		ret = 1;
 	}
 
-	if ((u64)conn->outstanding_credits + credit_charge > conn->vals->max_credits) {
+	if ((u64)conn->outstanding_credits + credit_charge > conn->total_credits) {
 		ksmbd_debug(SMB, "Limits exceeding the maximum allowable outstanding requests, given : %u, pending : %u\n",
 			    credit_charge, conn->outstanding_credits);
 		ret = 1;
diff --git a/fs/ksmbd/smb_common.c b/fs/ksmbd/smb_common.c
index 9a7e211dbf4f..a336715e35e5 100644
--- a/fs/ksmbd/smb_common.c
+++ b/fs/ksmbd/smb_common.c
@@ -140,8 +140,10 @@ int ksmbd_verify_smb_message(struct ksmbd_work *work)
 
 	hdr = work->request_buf;
 	if (*(__le32 *)hdr->Protocol == SMB1_PROTO_NUMBER &&
-	    hdr->Command == SMB_COM_NEGOTIATE)
+	    hdr->Command == SMB_COM_NEGOTIATE) {
+		work->conn->outstanding_credits += 1;
 		return 0;
+	}
 
 	return -EINVAL;
 }
-- 
2.17.1