Re: [PATCH] cifs: Collapse smbd_recv_*() into smbd_recv() and just use copy_to_iter()

[David Howells <dhowells@xxxxxxxxxx>]

Stefan Metzmacher <metze@xxxxxxxxx> wrote:

> Please keep the rfc1002_len variable as it's used in the log_read message
> below and it should by host byteorder.

So this change on top of the patch I posted?

@@ -1838,11 +1838,11 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
                         * transport layer is added
                         */
                        if (response->first_segment && size == 4) {
-                               unsigned int len =
+                               unsigned int rfc1002_len =
                                        data_length + remaining_data_length;
-                               __be32 rfc1002_len = cpu_to_be32(len);
-                               if (copy_to_iter(&rfc1002_len, sizeof(rfc1002_len),
-                                                &msg->msg_iter) != sizeof(rfc1002_len))
+                               __be32 rfc1002_hdr = cpu_to_be32(rfc1002_len);
+                               if (copy_to_iter(&rfc1002_hdr, sizeof(rfc1002_hdr),
+                                                &msg->msg_iter) != sizeof(rfc1002_hdr))
                                        return -EFAULT;
                                data_read = 4;
                                response->first_segment = false;

Btw, I'm changing the patch subject and description to:

    cifs: Fix reading into an ITER_FOLIOQ from the smbdirect code
    
    When performing a file read from RDMA, smbd_recv() prints an "Invalid msg
    type 4" error and fails the I/O.  This is due to the switch-statement there
    not handling the ITER_FOLIOQ handed down from netfslib.
    
    Fix this by collapsing smbd_recv_buf() and smbd_recv_page() into
    smbd_recv() and just using copy_to_iter() instead of memcpy().  This
    future-proofs the function too, in case more ITER_* types are added.
    
    Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
    Reported-by: Stefan Metzmacher <metze@xxxxxxxxx>
    Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
    cc: Steve French <stfrench@xxxxxxxxxxxxx>
    cc: Tom Talpey <tom@xxxxxxxxxx>
    cc: Paulo Alcantara (Red Hat) <pc@xxxxxxxxxxxxx>
    cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
    cc: linux-cifs@xxxxxxxxxxxxxxx
    cc: netfs@xxxxxxxxxxxxxxx
    cc: linux-fsdevel@xxxxxxxxxxxxxxx

David