cifs: multichannel: move channel selection above transport layer

Move the channel (TCP_Server_Info*) selection from the tranport
layer to higher in the call stack so that:

- credit handling is done with the server that will actually be used
  to send.
  * ->wait_mtu_credit
  * ->set_credits / set_credits
  * ->add_credits / add_credits
  * add_credits_and_wake_if

- potential reconnection (smb2_reconnect) done when initializing a
  request is checked and done with the server that will actually be
  used to send.

To do this:

- remove the cifs_pick_channel() call out of compound_send_recv()

- select channel and pass it down by adding a cifs_pick_channel(ses)
  call in:
  - smb311_posix_mkdir
  - SMB2_open
  - SMB2_ioctl
  - __SMB2_close
  - query_info
  - SMB2_change_notify
  - SMB2_flush
  - smb2_async_readv  (if none provided in context param)
  - SMB2_read         (if none provided in context param)
  - smb2_async_writev (if none provided in context param)
  - SMB2_write        (if none provided in context param)
  - SMB2_query_directory
  - send_set_info
  - SMB2_oplock_break
  - SMB311_posix_qfs_info
  - SMB2_QFS_info
  - SMB2_QFS_attr
  - smb2_lockv
  - SMB2_lease_break
    - smb2_compound_op
  - smb2_set_ea
  - smb2_ioctl_query_info
  - smb2_query_dir_first
  - smb2_query_info_comound
  - smb2_query_symlink
  - cifs_writepages
  - cifs_write_from_iter
  - cifs_send_async_read
  - cifs_read
  - cifs_readpages

- add TCP_Server_Info *server param argument to:
  - cifs_send_recv
  - compound_send_recv
  - SMB2_open_init
  - SMB2_query_info_init
  - SMB2_set_info_init
  - SMB2_close_init
  - SMB2_ioctl_init
  - smb2_iotcl_req_init
  - SMB2_query_directory_init
  - SMB2_notify_init
  - SMB2_flush_init
  - build_qfs_info_req
  - smb2_hdr_assemble
  - smb2_reconnect
  - fill_small_buf
  - smb2_plain_req_init
  - __smb2_plain_req_init

The read/write codepath is different than the rest as it is using
pages, io iterators and async calls. To deal with those we add a
server pointer in the cifs_writedata/cifs_readdata/cifs_io_parms
context struct and set it in:

- cifs_writepages      (wdata)
- cifs_write_from_iter (wdata)
- cifs_readpages       (rdata)
- cifs_send_async_read (rdata)

The [rw]data->server pointer is eventually copied to
cifs_io_parms->server to pass it down to SMB2_read/SMB2_write.
If SMB2_read/SMB2_write is called from a different place that doesn't
set the server field it will pick a channel.

Some places do not pick a channel and just use ses->server or
cifs_ses_server(ses). All cifs_ses_server(ses) calls are in codepaths
involving negprot/sess.setup.

- SMB2_negotiate         (binding channel)
- SMB2_sess_alloc_buffer (binding channel)
- SMB2_echo              (uses provided one)
- SMB2_logoff            (uses master)
- SMB2_tdis              (uses master)

(list not exhaustive)

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 54 insertions, 25 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 49c5c80f5d36..e97eb0050a0e 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -708,7 +708,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = pfid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, &utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, &utf16_path);
 	if (rc)
 		goto oshr_free;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -717,7 +718,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qi_iov;
 	rqst[1].rq_nvec = 1;
 
-	rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID,
+	rc = SMB2_query_info_init(tcon, server,
+				  &rqst[1], COMPOUND_FID,
 				  COMPOUND_FID, FILE_ALL_INFORMATION,
 				  SMB2_O_INFO_FILE, 0,
 				  sizeof(struct smb2_file_all_info) +
@@ -727,7 +729,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
 
 	smb2_set_related(&rqst[1]);
 
-	rc = compound_send_recv(xid, ses, flags, 2, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 2, rqst,
 				resp_buftype, rsp_iov);
 	mutex_lock(&tcon->crfid.fid_mutex);
 
@@ -1102,6 +1105,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	    struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	__le16 *utf16_path = NULL;
 	int ea_name_len = strlen(ea_name);
 	int flags = 0;
@@ -1190,7 +1194,8 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto sea_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -1216,7 +1221,8 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	size[0] = len;
 	data[0] = ea;
 
-	rc = SMB2_set_info_init(tcon, &rqst[1], COMPOUND_FID,
+	rc = SMB2_set_info_init(tcon, server,
+				&rqst[1], COMPOUND_FID,
 				COMPOUND_FID, current->tgid,
 				FILE_FULL_EA_INFORMATION,
 				SMB2_O_INFO_FILE, 0, data, size);
@@ -1228,10 +1234,12 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	memset(&close_iov, 0, sizeof(close_iov));
 	rqst[2].rq_iov = close_iov;
 	rqst[2].rq_nvec = 1;
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 	/* no need to bump num_remote_opens because handle immediately closed */
 
@@ -1473,6 +1481,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 	struct smb_rqst *rqst;
 	struct kvec *rsp_iov;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	char __user *arg = (char __user *)p;
 	struct smb_query_info qi;
 	struct smb_query_info __user *pqi;
@@ -1505,7 +1514,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 		return -EINVAL;
 	}
 
-	if (!ses || !(ses->server)) {
+	if (!ses || !server) {
 		kfree(vars);
 		return -EIO;
 	}
@@ -1552,7 +1561,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 		oparms.desired_access = FILE_READ_ATTRIBUTES | READ_CONTROL;
 	}
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, path);
 	if (rc)
 		goto iqinf_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -1566,7 +1576,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 			rqst[1].rq_iov = &vars->io_iov[0];
 			rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
 
-			rc = SMB2_ioctl_init(tcon, &rqst[1],
+			rc = SMB2_ioctl_init(tcon, server,
+					     &rqst[1],
 					     COMPOUND_FID, COMPOUND_FID,
 					     qi.info_type, true, buffer,
 					     qi.output_buffer_length,
@@ -1585,7 +1596,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 			size[0] = 8;
 			data[0] = buffer;
 
-			rc = SMB2_set_info_init(tcon, &rqst[1],
+			rc = SMB2_set_info_init(tcon, server,
+					&rqst[1],
 					COMPOUND_FID, COMPOUND_FID,
 					current->tgid,
 					FILE_END_OF_FILE_INFORMATION,
@@ -1595,7 +1607,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 		rqst[1].rq_iov = &vars->qi_iov[0];
 		rqst[1].rq_nvec = 1;
 
-		rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID,
+		rc = SMB2_query_info_init(tcon, server,
+				  &rqst[1], COMPOUND_FID,
 				  COMPOUND_FID, qi.file_info_class,
 				  qi.info_type, qi.additional_information,
 				  qi.input_buffer_length,
@@ -1615,12 +1628,14 @@ smb2_ioctl_query_info(const unsigned int xid,
 	rqst[2].rq_iov = &vars->close_iov[0];
 	rqst[2].rq_nvec = 1;
 
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	if (rc)
 		goto iqinf_exit;
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 	if (rc)
 		goto iqinf_exit;
@@ -2172,6 +2187,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cifs_open_parms oparms;
 	struct smb2_query_directory_rsp *qd_rsp = NULL;
 	struct smb2_create_rsp *op_rsp = NULL;
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
 
 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path)
@@ -2196,7 +2212,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto qdf_free;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -2209,7 +2226,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qd_iov;
 	rqst[1].rq_nvec = SMB2_QUERY_DIRECTORY_IOV_SIZE;
 
-	rc = SMB2_query_directory_init(xid, tcon, &rqst[1],
+	rc = SMB2_query_directory_init(xid, tcon, server,
+				       &rqst[1],
 				       COMPOUND_FID, COMPOUND_FID,
 				       0, srch_inf->info_level);
 	if (rc)
@@ -2217,7 +2235,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 
 	smb2_set_related(&rqst[1]);
 
-	rc = compound_send_recv(xid, tcon->ses, flags, 2, rqst,
+	rc = compound_send_recv(xid, tcon->ses, server,
+				flags, 2, rqst,
 				resp_buftype, rsp_iov);
 
 	/* If the open failed there is nothing to do */
@@ -2422,6 +2441,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 			 struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	int flags = 0;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
@@ -2452,7 +2472,8 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto qic_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -2461,7 +2482,8 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qi_iov;
 	rqst[1].rq_nvec = 1;
 
-	rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID, COMPOUND_FID,
+	rc = SMB2_query_info_init(tcon, server,
+				  &rqst[1], COMPOUND_FID, COMPOUND_FID,
 				  class, type, 0,
 				  output_len, 0,
 				  NULL);
@@ -2474,12 +2496,14 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[2].rq_iov = close_iov;
 	rqst[2].rq_nvec = 1;
 
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	if (rc)
 		goto qic_exit;
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 	if (rc) {
 		free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
@@ -2811,6 +2835,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	struct kvec err_iov = {NULL, 0};
 	struct smb2_err_rsp *err_buf = NULL;
 	struct smb2_symlink_err_rsp *symlink;
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
 	unsigned int sub_len;
 	unsigned int sub_offset;
 	unsigned int print_len;
@@ -2856,7 +2881,8 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto querty_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -2867,7 +2893,8 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = io_iov;
 	rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
 
-	rc = SMB2_ioctl_init(tcon, &rqst[1], fid.persistent_fid,
+	rc = SMB2_ioctl_init(tcon, server,
+			     &rqst[1], fid.persistent_fid,
 			     fid.volatile_fid, FSCTL_GET_REPARSE_POINT,
 			     true /* is_fctl */, NULL, 0,
 			     CIFSMaxBufSize -
@@ -2885,13 +2912,15 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[2].rq_iov = close_iov;
 	rqst[2].rq_nvec = 1;
 
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	if (rc)
 		goto querty_exit;
 
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, tcon->ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, tcon->ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 
 	create_rsp = rsp_iov[0].iov_base;