Commit bc205ed1 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Prepare credits code for a slot reservation 



that is essential for CIFS/SMB/SMB2 oplock breaks and SMB2 echos.

Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarPavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 5bc59498

fs/cifs/cifsglob.h

+12 −2
Original line number Diff line number Diff line
@@ -315,12 +315,22 @@ in_flight(struct TCP_Server_Info *server) 
	return num;

}



static inline int*

get_credits_field(struct TCP_Server_Info *server)

{

	/*

	 * This will change to switch statement when we reserve slots for echos

	 * and oplock breaks.

	 */

	return &server->credits;

}



static inline bool

has_credits(struct TCP_Server_Info *server)

has_credits(struct TCP_Server_Info *server, int *credits)

{

	int num;

	spin_lock(&server->req_lock);

	num = server->credits;

	num = *credits;

	spin_unlock(&server->req_lock);

	return num > 0;

}

fs/cifs/transport.c

+14 −8
Original line number Diff line number Diff line
@@ -255,26 +255,26 @@ smb_send(struct TCP_Server_Info *server, struct smb_hdr *smb_buffer, 
}



static int

wait_for_free_request(struct TCP_Server_Info *server, const int long_op)

wait_for_free_credits(struct TCP_Server_Info *server, const int optype,

		      int *credits)

{

	int rc;



	spin_lock(&server->req_lock);



	if (long_op == CIFS_ASYNC_OP) {

	if (optype == CIFS_ASYNC_OP) {

		/* oplock breaks must not be held up */

		server->in_flight++;

		server->credits--;

		*credits -= 1;

		spin_unlock(&server->req_lock);

		return 0;

	}



	while (1) {

		if (server->credits <= 0) {

		if (*credits <= 0) {

			spin_unlock(&server->req_lock);

			cifs_num_waiters_inc(server);

			rc = wait_event_killable(server->request_q,

						 has_credits(server));

						 has_credits(server, credits));

			cifs_num_waiters_dec(server);

			if (rc)

				return rc;
@@ -291,8 +291,8 @@ wait_for_free_request(struct TCP_Server_Info *server, const int long_op) 
			 */



			/* update # of requests on the wire to server */

			if (long_op != CIFS_BLOCKING_OP) {

				server->credits--;

			if (optype != CIFS_BLOCKING_OP) {

				*credits -= 1;

				server->in_flight++;

			}

			spin_unlock(&server->req_lock);
@@ -302,6 +302,12 @@ wait_for_free_request(struct TCP_Server_Info *server, const int long_op) 
	return 0;

}



static int

wait_for_free_request(struct TCP_Server_Info *server, const int optype)

{

	return wait_for_free_credits(server, optype, get_credits_field(server));

}



static int allocate_mid(struct cifs_ses *ses, struct smb_hdr *in_buf,

			struct mid_q_entry **ppmidQ)

{