diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index 8e75d689be46..e047f06c9b4f 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -795,7 +795,8 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, int i, j, rc = 0; int timeout, optype; struct mid_q_entry *midQ[MAX_COMPOUND]; - unsigned int credits = 0; + bool cancelled_mid[MAX_COMPOUND] = {false}; + unsigned int credits[MAX_COMPOUND] = {0}; char *buf; timeout = flags & CIFS_TIMEOUT_MASK; @@ -813,13 +814,31 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, return -ENOENT; /* - * Ensure that we do not send more than 50 overlapping requests - * to the same server. We may make this configurable later or - * use ses->maxReq. + * Ensure we obtain 1 credit per request in the compound chain. + * It can be optimized further by waiting for all the credits + * at once but this can wait long enough if we don't have enough + * credits due to some heavy operations in progress or the server + * not granting us much, so a fallback to the current approach is + * needed anyway. */ - rc = wait_for_free_request(ses->server, timeout, optype); - if (rc) - return rc; + for (i = 0; i < num_rqst; i++) { + rc = wait_for_free_request(ses->server, timeout, optype); + if (rc) { + /* + * We haven't sent an SMB packet to the server yet but + * we already obtained credits for i requests in the + * compound chain - need to return those credits back + * for future use. Note that we need to call add_credits + * multiple times to match the way we obtained credits + * in the first place and to account for in flight + * requests correctly. + */ + for (j = 0; j < i; j++) + add_credits(ses->server, 1, optype); + return rc; + } + credits[i] = 1; + } /* * Make sure that we sign in the same order that we send on this socket @@ -835,8 +854,10 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, for (j = 0; j < i; j++) cifs_delete_mid(midQ[j]); mutex_unlock(&ses->server->srv_mutex); + /* Update # of requests on wire to server */ - add_credits(ses->server, 1, optype); + for (j = 0; j < num_rqst; j++) + add_credits(ses->server, credits[j], optype); return PTR_ERR(midQ[i]); } @@ -883,17 +904,16 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) { midQ[i]->mid_flags |= MID_WAIT_CANCELLED; midQ[i]->callback = DeleteMidQEntry; - spin_unlock(&GlobalMid_Lock); - add_credits(ses->server, 1, optype); - return rc; + cancelled_mid[i] = true; } spin_unlock(&GlobalMid_Lock); } } for (i = 0; i < num_rqst; i++) - if (midQ[i]->resp_buf) - credits += ses->server->ops->get_credits(midQ[i]); + if (!cancelled_mid[i] && midQ[i]->resp_buf + && (midQ[i]->mid_state == MID_RESPONSE_RECEIVED)) + credits[i] = ses->server->ops->get_credits(midQ[i]); for (i = 0; i < num_rqst; i++) { if (rc < 0) @@ -901,8 +921,9 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, rc = cifs_sync_mid_result(midQ[i], ses->server); if (rc != 0) { - add_credits(ses->server, credits, optype); - return rc; + /* mark this mid as cancelled to not free it below */ + cancelled_mid[i] = true; + goto out; } if (!midQ[i]->resp_buf || @@ -949,9 +970,11 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, * This is prevented above by using a noop callback that will not * wake this thread except for the very last PDU. */ - for (i = 0; i < num_rqst; i++) - cifs_delete_mid(midQ[i]); - add_credits(ses->server, credits, optype); + for (i = 0; i < num_rqst; i++) { + if (!cancelled_mid[i]) + cifs_delete_mid(midQ[i]); + add_credits(ses->server, credits[i], optype); + } return rc; }