GCC versions from 4.9 to 6.3 produce a false-positive warning when
dealing with a conditional spin_lock_irqsave():
fs/cifs/smbdirect.c: In function 'smbd_recv_buf':
include/linux/spinlock.h:260:3: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized]
This function calls some sleeping interfaces, so it is clear that it
does not get called with interrupts disabled and there is no need
to save the irq state before taking the spinlock. This lets us
remove the variable, which makes the function slightly more efficient
and avoids the warning.
A further cleanup could do the same change for other functions in this
file, but I did not want to take this too far for now.
Fixes: ac69f66e54ca ("CIFS: SMBD: Implement function to receive data via RDMA receive")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steve French <smfrench@gmail.com>
Fixes: 07495ff5d9bc ("CIFS: SMBD: Establish SMB Direct connection")
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Long Li <longli@microsoft.com>
Memory registration is used for transferring payload via RDMA read or write.
After I/O is done, memory registrations are recovered and reused. This
process can be time consuming and is done in a work queue.
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
The transport doesn't maintain send buffers or send queue for transferring
payload via RDMA send. There is no data copy in the transport on send.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
On the receive path, the transport maintains receive buffers and a reassembly
queue for transferring payload via RDMA recv. There is data copy in the
transport on recv when it copies the payload to upper layer.
The transport recognizes the RFC1002 header length use in the SMB
upper layer payloads in CIFS. Because this length is mainly used for TCP and
not applicable to RDMA, it is handled as a out-of-band information and is
never sent over the wire, and the trasnport behaves like TCP to upper layer
by processing and exposing the length correctly on data payloads.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Add function to tear down a SMB Direct connection. This is used by upper layer
to free all SMB Direct connection and transport resources.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Add function to implement a reconnect to SMB Direct. This involves tearing down
the current connection and establishing/negotiating a new connection.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
The upper layer calls this function to connect to peer through SMB Direct.
Each SMB Direct connection is based on a RDMA RC Queue Pair.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Add code to implement the core functions to establish a SMB Direct connection.
1. Establish an RDMA connection to SMB server.
2. Negotiate and setup SMB Direct protocol.
3. Implement idle connection timer and credit management.
SMB Direct is enabled by setting CONFIG_CIFS_SMB_DIRECT.
Add to Makefile to enable building SMB Direct.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
To prepare for protocol implementation, add constants and user-configurable
values for the SMB Direct protocol.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Ronnie Sahlberg <lsahlber.redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
