[RFC PATCH 32/36] cifs: Convert SMB2 Write request

From: David Howells

Date: Tue May 19 2026 - 06:46:48 EST


Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Steve French <sfrench@xxxxxxxxx>
cc: Paulo Alcantara <pc@xxxxxxxxxxxxx>
cc: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
cc: Tom Talpey <tom@xxxxxxxxxx>
cc: linux-cifs@xxxxxxxxxxxxxxx
cc: netfs@xxxxxxxxxxxxxxx
cc: linux-fsdevel@xxxxxxxxxxxxxxx
---
fs/smb/client/smb2pdu.c | 69 +++++++++++++++++++++--------------------
1 file changed, 35 insertions(+), 34 deletions(-)

diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index b2140cb1662e..b434aaf15dba 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -5338,10 +5338,8 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
struct smb2_hdr *shdr;
struct cifs_tcon *tcon = tlink_tcon(wdata->req->cfile->tlink);
struct TCP_Server_Info *server = wdata->server;
- struct kvec iov[1];
- unsigned int total_len, xid = wdata->xid;
- int credit_request;
- int rc = -EACCES, flags = 0;
+ unsigned int xid = wdata->xid;
+ int rc = -EACCES;

/*
* in future we may get cifs_io_parms passed in from the caller,
@@ -5357,41 +5355,39 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
.pid = wdata->req->pid,
};

- smb = smb_message_alloc(smb2_command_trace_write, GFP_NOFS);
+ size_t proto_len = sizeof(*req);
+
+#ifdef CONFIG_CIFS_SMB_DIRECT
+ bool rdma_offload = smb3_use_rdma_offload(&io_parms);
+
+ if (rdma_offload)
+ proto_len += sizeof(struct smbdirect_buffer_descriptor_v1);
+#endif
+
+ smb = smb2_create_request(SMB2_WRITE, server, tcon,
+ sizeof(*req), proto_len, wdata->subreq.len,
+ SMB2_REQ_DYNAMIC);
if (!smb) {
rc = -ENOMEM;
goto out;
}
+ req = smb->request;
+ shdr = &req->hdr;

- rc = smb2_plain_req_init(SMB2_WRITE, tcon, server,
- (void **) &req, &total_len);
- if (rc) {
- mempool_free(smb, &smb_message_pool);
- goto out;
- }
-
- iov[0].iov_len = total_len;
- iov[0].iov_base = (char *)req;
- total_len += wdata->subreq.len;
-
- smb->rqst.rq_iov = iov;
- smb->rqst.rq_nvec = 1;
- smb->command = SMB2_WRITE;
+ smb->subreq = wdata;
+ smb->credits = wdata->credits;
smb->request = req;
- smb->total_len = total_len;
smb->callback = smb2_writev_callback;
smb->subreq = wdata;

- iov_iter_bvec_queue(&smb->rqst.rq_iter, ITER_SOURCE,
+ iov_iter_bvec_queue(&smb->data_iter, ITER_SOURCE,
wdata->subreq.content.bvecq, wdata->subreq.content.slot,
wdata->subreq.content.offset, wdata->subreq.len);

if (smb3_encryption_required(tcon))
- flags |= CIFS_TRANSFORM_REQ;
-
- shdr = (struct smb2_hdr *)req;
- shdr->Id.SyncId.ProcessId = cpu_to_le32(io_parms.pid);
+ smb->sr_flags |= CIFS_TRANSFORM_REQ;

+ shdr->Id.SyncId.ProcessId = cpu_to_le32(io_parms.pid);
req->PersistentFileId = io_parms.persistent_fid;
req->VolatileFileId = io_parms.volatile_fid;
req->WriteChannelInfoOffset = 0;
@@ -5417,7 +5413,7 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
* If we want to do a server RDMA read, fill in and append
* smbdirect_buffer_descriptor_v1 to the end of write request
*/
- if (smb3_use_rdma_offload(&io_parms)) {
+ if (rdma_offload) {
struct smbdirect_buffer_descriptor_v1 *v1;
struct iov_iter iter;
bool need_invalidate = server->dialect == SMB30_PROT_ID;
@@ -5467,9 +5463,12 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
io_parms.offset, io_parms.length, iov_iter_count(&smb->rqst.rq_iter));

if (wdata->credits.value > 0) {
- shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->subreq.len,
- SMB2_MAX_BUFFER_SIZE));
- credit_request = le16_to_cpu(shdr->CreditCharge) + 8;
+ u32 credit_charge = DIV_ROUND_UP(wdata->subreq.len,
+ SMB2_MAX_BUFFER_SIZE);
+ int credit_request;
+
+ shdr->CreditCharge = cpu_to_le16(credit_charge);
+ credit_request = credit_charge + 8;
if (server->credits >= server->max_credits)
shdr->CreditRequest = cpu_to_le16(0);
else
@@ -5481,15 +5480,18 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
if (rc)
goto async_writev_out;

- flags |= CIFS_HAS_CREDITS;
+ smb->sr_flags |= CIFS_HAS_CREDITS;
}

/* XXX: compression + encryption is unsupported for now */
- if (((flags & CIFS_TRANSFORM_REQ) != CIFS_TRANSFORM_REQ) &&
+ if (((smb->sr_flags & CIFS_TRANSFORM_REQ) != CIFS_TRANSFORM_REQ) &&
should_compress(tcon, smb))
- flags |= CIFS_COMPRESS_REQ;
+ smb->sr_flags |= CIFS_COMPRESS_REQ;

- rc = cifs_call_async(server, smb, flags, &wdata->credits);
+ iov_iter_bvec_queue(&smb->req_iter, ITER_SOURCE, &smb->bvecq, 0, 0,
+ smb->data_offset);
+
+ rc = cifs_call_async(server, smb, smb->sr_flags, &wdata->credits);
/* Can't touch wdata if rc == 0 */
if (rc) {
trace_smb3_write_err(wdata->rreq->debug_id,
@@ -5505,7 +5507,6 @@ smb2_async_writev(struct cifs_io_subrequest *wdata)
}

async_writev_out:
- cifs_small_buf_release(req);
smb_put_messages(smb);
out:
/* if the send error is retryable, let netfs know about it */