Release 4.12 include/linux/scif.h

Directory: include/linux

/*
* Intel MIC Platform Software Stack (MPSS)
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2014 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* BSD LICENSE
*
* Copyright(c) 2014 Intel Corporation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Intel SCIF driver.
*
*/
#ifndef __SCIF_H__

#define __SCIF_H__

#include <linux/types.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/scif_ioctl.h>

#define SCIF_ACCEPT_SYNC 1

#define SCIF_SEND_BLOCK 1

#define SCIF_RECV_BLOCK 1

enum {

SCIF_PROT_READ = (1 << 0),

SCIF_PROT_WRITE = (1 << 1)
};

enum {

SCIF_MAP_FIXED = 0x10,

SCIF_MAP_KERNEL = 0x20,
};

enum {

SCIF_FENCE_INIT_SELF = (1 << 0),

SCIF_FENCE_INIT_PEER = (1 << 1),

SCIF_SIGNAL_LOCAL = (1 << 4),

SCIF_SIGNAL_REMOTE = (1 << 5)
};

enum {

SCIF_RMA_USECPU = (1 << 0),

SCIF_RMA_USECACHE = (1 << 1),

SCIF_RMA_SYNC = (1 << 2),

SCIF_RMA_ORDERED = (1 << 3)
};

/* End of SCIF Admin Reserved Ports */

#define SCIF_ADMIN_PORT_END 1024

/* End of SCIF Reserved Ports */

#define SCIF_PORT_RSVD 1088

typedef struct scif_endpt *scif_epd_t;

typedef struct scif_pinned_pages *scif_pinned_pages_t;

/**
* struct scif_range - SCIF registered range used in kernel mode
* @cookie: cookie used internally by SCIF
* @nr_pages: number of pages of PAGE_SIZE
* @prot_flags: R/W protection
* @phys_addr: Array of bus addresses
* @va: Array of kernel virtual addresses backed by the pages in the phys_addr
* array. The va is populated only when called on the host for a remote
* SCIF connection on MIC. This is required to support the use case of DMA
* between MIC and another device which is not a SCIF node e.g., an IB or
* ethernet NIC.
*/

dma_addr_t *phys_addr;

void __iomem **va;
};

/**
* struct scif_pollepd - SCIF endpoint to be monitored via scif_poll
* @epd: SCIF endpoint
* @events: requested events
* @revents: returned events
*/

struct scif_pollepd {

scif_epd_t epd;

short events;

short revents;
};

/**
* scif_peer_dev - representation of a peer SCIF device
*
* Peer devices show up as PCIe devices for the mgmt node but not the cards.
* The mgmt node discovers all the cards on the PCIe bus and informs the other
* cards about their peers. Upon notification of a peer a node adds a peer
* device to the peer bus to maintain symmetry in the way devices are
* discovered across all nodes in the SCIF network.
*
* @dev: underlying device
* @dnode - The destination node which this device will communicate with.
*/

struct scif_peer_dev {

struct device dev;

u8 dnode;
};

/**
* scif_client - representation of a SCIF client
* @name: client name
* @probe - client method called when a peer device is registered
* @remove - client method called when a peer device is unregistered
* @si - subsys_interface used internally for implementing SCIF clients
*/

struct scif_client {

const char *name;

void (*probe)(struct scif_peer_dev *spdev);

void (*remove)(struct scif_peer_dev *spdev);

struct subsys_interface si;
};

#define SCIF_OPEN_FAILED ((scif_epd_t)-1)

#define SCIF_REGISTER_FAILED ((off_t)-1)

#define SCIF_MMAP_FAILED ((void *)-1)

/**
* scif_open() - Create an endpoint
*
* Return:
* Upon successful completion, scif_open() returns an endpoint descriptor to
* be used in subsequent SCIF functions calls to refer to that endpoint;
* otherwise in user mode SCIF_OPEN_FAILED (that is ((scif_epd_t)-1)) is
* returned and errno is set to indicate the error; in kernel mode a NULL
* scif_epd_t is returned.
*
* Errors:
* ENOMEM - Insufficient kernel memory was available
*/
scif_epd_t scif_open(void);

/**
* scif_bind() - Bind an endpoint to a port
* @epd: endpoint descriptor
* @pn: port number
*
* scif_bind() binds endpoint epd to port pn, where pn is a port number on the
* local node. If pn is zero, a port number greater than or equal to
* SCIF_PORT_RSVD is assigned and returned. Each endpoint may be bound to
* exactly one local port. Ports less than 1024 when requested can only be bound
* by system (or root) processes or by processes executed by privileged users.
*
* Return:
* Upon successful completion, scif_bind() returns the port number to which epd
* is bound; otherwise in user mode -1 is returned and errno is set to
* indicate the error; in kernel mode the negative of one of the following
* errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* EINVAL - the endpoint or the port is already bound
* EISCONN - The endpoint is already connected
* ENOSPC - No port number available for assignment
* EACCES - The port requested is protected and the user is not the superuser
*/
int scif_bind(scif_epd_t epd, u16 pn);

/**
* scif_listen() - Listen for connections on an endpoint
* @epd: endpoint descriptor
* @backlog: maximum pending connection requests
*
* scif_listen() marks the endpoint epd as a listening endpoint - that is, as
* an endpoint that will be used to accept incoming connection requests. Once
* so marked, the endpoint is said to be in the listening state and may not be
* used as the endpoint of a connection.
*
* The endpoint, epd, must have been bound to a port.
*
* The backlog argument defines the maximum length to which the queue of
* pending connections for epd may grow. If a connection request arrives when
* the queue is full, the client may receive an error with an indication that
* the connection was refused.
*
* Return:
* Upon successful completion, scif_listen() returns 0; otherwise in user mode
* -1 is returned and errno is set to indicate the error; in kernel mode the
* negative of one of the following errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* EINVAL - the endpoint is not bound to a port
* EISCONN - The endpoint is already connected or listening
*/
int scif_listen(scif_epd_t epd, int backlog);

/**
* scif_connect() - Initiate a connection on a port
* @epd: endpoint descriptor
* @dst: global id of port to which to connect
*
* The scif_connect() function requests the connection of endpoint epd to remote
* port dst. If the connection is successful, a peer endpoint, bound to dst, is
* created on node dst.node. On successful return, the connection is complete.
*
* If the endpoint epd has not already been bound to a port, scif_connect()
* will bind it to an unused local port.
*
* A connection is terminated when an endpoint of the connection is closed,
* either explicitly by scif_close(), or when a process that owns one of the
* endpoints of the connection is terminated.
*
* In user space, scif_connect() supports an asynchronous connection mode
* if the application has set the O_NONBLOCK flag on the endpoint via the
* fcntl() system call. Setting this flag will result in the calling process
* not to wait during scif_connect().
*
* Return:
* Upon successful completion, scif_connect() returns the port ID to which the
* endpoint, epd, is bound; otherwise in user mode -1 is returned and errno is
* set to indicate the error; in kernel mode the negative of one of the
* following errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNREFUSED - The destination was not listening for connections or refused
* the connection request
* EINVAL - dst.port is not a valid port ID
* EISCONN - The endpoint is already connected
* ENOMEM - No buffer space is available
* ENODEV - The destination node does not exist, or the node is lost or existed,
* but is not currently in the network since it may have crashed
* ENOSPC - No port number available for assignment
* EOPNOTSUPP - The endpoint is listening and cannot be connected
*/
int scif_connect(scif_epd_t epd, struct scif_port_id *dst);

/**
* scif_accept() - Accept a connection on an endpoint
* @epd: endpoint descriptor
* @peer: global id of port to which connected
* @newepd: new connected endpoint descriptor
* @flags: flags
*
* The scif_accept() call extracts the first connection request from the queue
* of pending connections for the port on which epd is listening. scif_accept()
* creates a new endpoint, bound to the same port as epd, and allocates a new
* SCIF endpoint descriptor, returned in newepd, for the endpoint. The new
* endpoint is connected to the endpoint through which the connection was
* requested. epd is unaffected by this call, and remains in the listening
* state.
*
* On successful return, peer holds the global port identifier (node id and
* local port number) of the port which requested the connection.
*
* A connection is terminated when an endpoint of the connection is closed,
* either explicitly by scif_close(), or when a process that owns one of the
* endpoints of the connection is terminated.
*
* The number of connections that can (subsequently) be accepted on epd is only
* limited by system resources (memory).
*
* The flags argument is formed by OR'ing together zero or more of the
* following values.
* SCIF_ACCEPT_SYNC - block until a connection request is presented. If
* SCIF_ACCEPT_SYNC is not in flags, and no pending
* connections are present on the queue, scif_accept()
* fails with an EAGAIN error
*
* In user mode, the select() and poll() functions can be used to determine
* when there is a connection request. In kernel mode, the scif_poll()
* function may be used for this purpose. A readable event will be delivered
* when a connection is requested.
*
* Return:
* Upon successful completion, scif_accept() returns 0; otherwise in user mode
* -1 is returned and errno is set to indicate the error; in kernel mode the
* negative of one of the following errors is returned.
*
* Errors:
* EAGAIN - SCIF_ACCEPT_SYNC is not set and no connections are present to be
* accepted or SCIF_ACCEPT_SYNC is not set and remote node failed to complete
* its connection request
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* EINTR - Interrupted function
* EINVAL - epd is not a listening endpoint, or flags is invalid, or peer is
* NULL, or newepd is NULL
* ENODEV - The requesting node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOMEM - Not enough space
* ENOENT - Secondary part of epd registration failed
*/
int scif_accept(scif_epd_t epd, struct scif_port_id *peer, scif_epd_t
*newepd, int flags);

/**
* scif_close() - Close an endpoint
* @epd: endpoint descriptor
*
* scif_close() closes an endpoint and performs necessary teardown of
* facilities associated with that endpoint.
*
* If epd is a listening endpoint then it will no longer accept connection
* requests on the port to which it is bound. Any pending connection requests
* are rejected.
*
* If epd is a connected endpoint, then its peer endpoint is also closed. RMAs
* which are in-process through epd or its peer endpoint will complete before
* scif_close() returns. Registered windows of the local and peer endpoints are
* released as if scif_unregister() was called against each window.
*
* Closing a SCIF endpoint does not affect local registered memory mapped by
* a SCIF endpoint on a remote node. The local memory remains mapped by the peer
* SCIF endpoint explicitly removed by calling munmap(..) by the peer.
*
* If the peer endpoint's receive queue is not empty at the time that epd is
* closed, then the peer endpoint can be passed as the endpoint parameter to
* scif_recv() until the receive queue is empty.
*
* epd is freed and may no longer be accessed.
*
* Return:
* Upon successful completion, scif_close() returns 0; otherwise in user mode
* -1 is returned and errno is set to indicate the error; in kernel mode the
* negative of one of the following errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
*/
int scif_close(scif_epd_t epd);

/**
* scif_send() - Send a message
* @epd: endpoint descriptor
* @msg: message buffer address
* @len: message length
* @flags: blocking mode flags
*
* scif_send() sends data to the peer of endpoint epd. Up to len bytes of data
* are copied from memory starting at address msg. On successful execution the
* return value of scif_send() is the number of bytes that were sent, and is
* zero if no bytes were sent because len was zero. scif_send() may be called
* only when the endpoint is in a connected state.
*
* If a scif_send() call is non-blocking, then it sends only those bytes which
* can be sent without waiting, up to a maximum of len bytes.
*
* If a scif_send() call is blocking, then it normally returns after sending
* all len bytes. If a blocking call is interrupted or the connection is
* reset, the call is considered successful if some bytes were sent or len is
* zero, otherwise the call is considered unsuccessful.
*
* In user mode, the select() and poll() functions can be used to determine
* when the send queue is not full. In kernel mode, the scif_poll() function
* may be used for this purpose.
*
* It is recommended that scif_send()/scif_recv() only be used for short
* control-type message communication between SCIF endpoints. The SCIF RMA
* APIs are expected to provide better performance for transfer sizes of
* 1024 bytes or longer for the current MIC hardware and software
* implementation.
*
* scif_send() will block until the entire message is sent if SCIF_SEND_BLOCK
* is passed as the flags argument.
*
* Return:
* Upon successful completion, scif_send() returns the number of bytes sent;
* otherwise in user mode -1 is returned and errno is set to indicate the
* error; in kernel mode the negative of one of the following errors is
* returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - flags is invalid, or len is negative
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOMEM - Not enough space
* ENOTCONN - The endpoint is not connected
*/
int scif_send(scif_epd_t epd, void *msg, int len, int flags);

/**
* scif_recv() - Receive a message
* @epd: endpoint descriptor
* @msg: message buffer address
* @len: message buffer length
* @flags: blocking mode flags
*
* scif_recv() receives data from the peer of endpoint epd. Up to len bytes of
* data are copied to memory starting at address msg. On successful execution
* the return value of scif_recv() is the number of bytes that were received,
* and is zero if no bytes were received because len was zero. scif_recv() may
* be called only when the endpoint is in a connected state.
*
* If a scif_recv() call is non-blocking, then it receives only those bytes
* which can be received without waiting, up to a maximum of len bytes.
*
* If a scif_recv() call is blocking, then it normally returns after receiving
* all len bytes. If the blocking call was interrupted due to a disconnection,
* subsequent calls to scif_recv() will copy all bytes received upto the point
* of disconnection.
*
* In user mode, the select() and poll() functions can be used to determine
* when data is available to be received. In kernel mode, the scif_poll()
* function may be used for this purpose.
*
* It is recommended that scif_send()/scif_recv() only be used for short
* control-type message communication between SCIF endpoints. The SCIF RMA
* APIs are expected to provide better performance for transfer sizes of
* 1024 bytes or longer for the current MIC hardware and software
* implementation.
*
* scif_recv() will block until the entire message is received if
* SCIF_RECV_BLOCK is passed as the flags argument.
*
* Return:
* Upon successful completion, scif_recv() returns the number of bytes
* received; otherwise in user mode -1 is returned and errno is set to
* indicate the error; in kernel mode the negative of one of the following
* errors is returned.
*
* Errors:
* EAGAIN - The destination node is returning from a low power state
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - flags is invalid, or len is negative
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOMEM - Not enough space
* ENOTCONN - The endpoint is not connected
*/
int scif_recv(scif_epd_t epd, void *msg, int len, int flags);

/**
* scif_register() - Mark a memory region for remote access.
* @epd: endpoint descriptor
* @addr: starting virtual address
* @len: length of range
* @offset: offset of window
* @prot_flags: read/write protection flags
* @map_flags: mapping flags
*
* The scif_register() function opens a window, a range of whole pages of the
* registered address space of the endpoint epd, starting at offset po and
* continuing for len bytes. The value of po, further described below, is a
* function of the parameters offset and len, and the value of map_flags. Each
* page of the window represents the physical memory page which backs the
* corresponding page of the range of virtual address pages starting at addr
* and continuing for len bytes. addr and len are constrained to be multiples
* of the page size. A successful scif_register() call returns po.
*
* When SCIF_MAP_FIXED is set in the map_flags argument, po will be offset
* exactly, and offset is constrained to be a multiple of the page size. The
* mapping established by scif_register() will not replace any existing
* registration; an error is returned if any page within the range [offset,
* offset + len - 1] intersects an existing window.
*
* When SCIF_MAP_FIXED is not set, the implementation uses offset in an
* implementation-defined manner to arrive at po. The po value so chosen will
* be an area of the registered address space that the implementation deems
* suitable for a mapping of len bytes. An offset value of 0 is interpreted as
* granting the implementation complete freedom in selecting po, subject to
* constraints described below. A non-zero value of offset is taken to be a
* suggestion of an offset near which the mapping should be placed. When the
* implementation selects a value for po, it does not replace any extant
* window. In all cases, po will be a multiple of the page size.
*
* The physical pages which are so represented by a window are available for
* access in calls to mmap(), scif_readfrom(), scif_writeto(),
* scif_vreadfrom(), and scif_vwriteto(). While a window is registered, the
* physical pages represented by the window will not be reused by the memory
* subsystem for any other purpose. Note that the same physical page may be
* represented by multiple windows.
*
* Subsequent operations which change the memory pages to which virtual
* addresses are mapped (such as mmap(), munmap()) have no effect on
* existing window.
*
* If the process will fork(), it is recommended that the registered
* virtual address range be marked with MADV_DONTFORK. Doing so will prevent
* problems due to copy-on-write semantics.
*
* The prot_flags argument is formed by OR'ing together one or more of the
* following values.
* SCIF_PROT_READ - allow read operations from the window
* SCIF_PROT_WRITE - allow write operations to the window
*
* Return:
* Upon successful completion, scif_register() returns the offset at which the
* mapping was placed (po); otherwise in user mode SCIF_REGISTER_FAILED (that
* is (off_t *)-1) is returned and errno is set to indicate the error; in
* kernel mode the negative of one of the following errors is returned.
*
* Errors:
* EADDRINUSE - SCIF_MAP_FIXED is set in map_flags, and pages in the range
* [offset, offset + len -1] are already registered
* EAGAIN - The mapping could not be performed due to lack of resources
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - map_flags is invalid, or prot_flags is invalid, or SCIF_MAP_FIXED is
* set in flags, and offset is not a multiple of the page size, or addr is not a
* multiple of the page size, or len is not a multiple of the page size, or is
* 0, or offset is negative
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOMEM - Not enough space
* ENOTCONN -The endpoint is not connected
*/
off_t scif_register(scif_epd_t epd, void *addr, size_t len, off_t offset,
int prot_flags, int map_flags);

/**
* scif_unregister() - Mark a memory region for remote access.
* @epd: endpoint descriptor
* @offset: start of range to unregister
* @len: length of range to unregister
*
* The scif_unregister() function closes those previously registered windows
* which are entirely within the range [offset, offset + len - 1]. It is an
* error to specify a range which intersects only a subrange of a window.
*
* On a successful return, pages within the window may no longer be specified
* in calls to mmap(), scif_readfrom(), scif_writeto(), scif_vreadfrom(),
* scif_vwriteto(), scif_get_pages, and scif_fence_signal(). The window,
* however, continues to exist until all previous references against it are
* removed. A window is referenced if there is a mapping to it created by
* mmap(), or if scif_get_pages() was called against the window
* (and the pages have not been returned via scif_put_pages()). A window is
* also referenced while an RMA, in which some range of the window is a source
* or destination, is in progress. Finally a window is referenced while some
* offset in that window was specified to scif_fence_signal(), and the RMAs
* marked by that call to scif_fence_signal() have not completed. While a
* window is in this state, its registered address space pages are not
* available for use in a new registered window.
*
* When all such references to the window have been removed, its references to
* all the physical pages which it represents are removed. Similarly, the
* registered address space pages of the window become available for
* registration in a new window.
*
* Return:
* Upon successful completion, scif_unregister() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned. In the event of an
* error, no windows are unregistered.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - the range [offset, offset + len - 1] intersects a subrange of a
* window, or offset is negative
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - Offsets in the range [offset, offset + len - 1] are invalid for the
* registered address space of epd
*/
int scif_unregister(scif_epd_t epd, off_t offset, size_t len);

/**
* scif_readfrom() - Copy from a remote address space
* @epd: endpoint descriptor
* @loffset: offset in local registered address space to
* which to copy
* @len: length of range to copy
* @roffset: offset in remote registered address space
* from which to copy
* @rma_flags: transfer mode flags
*
* scif_readfrom() copies len bytes from the remote registered address space of
* the peer of endpoint epd, starting at the offset roffset to the local
* registered address space of epd, starting at the offset loffset.
*
* Each of the specified ranges [loffset, loffset + len - 1] and [roffset,
* roffset + len - 1] must be within some registered window or windows of the
* local and remote nodes. A range may intersect multiple registered windows,
* but only if those windows are contiguous in the registered address space.
*
* If rma_flags includes SCIF_RMA_USECPU, then the data is copied using
* programmed read/writes. Otherwise the data is copied using DMA. If rma_-
* flags includes SCIF_RMA_SYNC, then scif_readfrom() will return after the
* transfer is complete. Otherwise, the transfer may be performed asynchron-
* ously. The order in which any two asynchronous RMA operations complete
* is non-deterministic. The synchronization functions, scif_fence_mark()/
* scif_fence_wait() and scif_fence_signal(), can be used to synchronize to
* the completion of asynchronous RMA operations on the same endpoint.
*
* The DMA transfer of individual bytes is not guaranteed to complete in
* address order. If rma_flags includes SCIF_RMA_ORDERED, then the last
* cacheline or partial cacheline of the source range will become visible on
* the destination node after all other transferred data in the source
* range has become visible on the destination node.
*
* The optimal DMA performance will likely be realized if both
* loffset and roffset are cacheline aligned (are a multiple of 64). Lower
* performance will likely be realized if loffset and roffset are not
* cacheline aligned but are separated by some multiple of 64. The lowest level
* of performance is likely if loffset and roffset are not separated by a
* multiple of 64.
*
* The rma_flags argument is formed by ORing together zero or more of the
* following values.
* SCIF_RMA_USECPU - perform the transfer using the CPU, otherwise use the DMA
* engine.
* SCIF_RMA_SYNC - perform the transfer synchronously, returning after the
* transfer has completed. Passing this flag results in the
* current implementation busy waiting and consuming CPU cycles
* while the DMA transfer is in progress for best performance by
* avoiding the interrupt latency.
* SCIF_RMA_ORDERED - ensure that the last cacheline or partial cacheline of
* the source range becomes visible on the destination node
* after all other transferred data in the source range has
* become visible on the destination
*
* Return:
* Upon successful completion, scif_readfrom() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned.
*
* Errors:
* EACCESS - Attempt to write to a read-only range
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - rma_flags is invalid
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - The range [loffset, loffset + len - 1] is invalid for the registered
* address space of epd, or, The range [roffset, roffset + len - 1] is invalid
* for the registered address space of the peer of epd, or loffset or roffset
* is negative
*/
int scif_readfrom(scif_epd_t epd, off_t loffset, size_t len, off_t
roffset, int rma_flags);

/**
* scif_writeto() - Copy to a remote address space
* @epd: endpoint descriptor
* @loffset: offset in local registered address space
* from which to copy
* @len: length of range to copy
* @roffset: offset in remote registered address space to
* which to copy
* @rma_flags: transfer mode flags
*
* scif_writeto() copies len bytes from the local registered address space of
* epd, starting at the offset loffset to the remote registered address space
* of the peer of endpoint epd, starting at the offset roffset.
*
* Each of the specified ranges [loffset, loffset + len - 1] and [roffset,
* roffset + len - 1] must be within some registered window or windows of the
* local and remote nodes. A range may intersect multiple registered windows,
* but only if those windows are contiguous in the registered address space.
*
* If rma_flags includes SCIF_RMA_USECPU, then the data is copied using
* programmed read/writes. Otherwise the data is copied using DMA. If rma_-
* flags includes SCIF_RMA_SYNC, then scif_writeto() will return after the
* transfer is complete. Otherwise, the transfer may be performed asynchron-
* ously. The order in which any two asynchronous RMA operations complete
* is non-deterministic. The synchronization functions, scif_fence_mark()/
* scif_fence_wait() and scif_fence_signal(), can be used to synchronize to
* the completion of asynchronous RMA operations on the same endpoint.
*
* The DMA transfer of individual bytes is not guaranteed to complete in
* address order. If rma_flags includes SCIF_RMA_ORDERED, then the last
* cacheline or partial cacheline of the source range will become visible on
* the destination node after all other transferred data in the source
* range has become visible on the destination node.
*
* The optimal DMA performance will likely be realized if both
* loffset and roffset are cacheline aligned (are a multiple of 64). Lower
* performance will likely be realized if loffset and roffset are not cacheline
* aligned but are separated by some multiple of 64. The lowest level of
* performance is likely if loffset and roffset are not separated by a multiple
* of 64.
*
* The rma_flags argument is formed by ORing together zero or more of the
* following values.
* SCIF_RMA_USECPU - perform the transfer using the CPU, otherwise use the DMA
* engine.
* SCIF_RMA_SYNC - perform the transfer synchronously, returning after the
* transfer has completed. Passing this flag results in the
* current implementation busy waiting and consuming CPU cycles
* while the DMA transfer is in progress for best performance by
* avoiding the interrupt latency.
* SCIF_RMA_ORDERED - ensure that the last cacheline or partial cacheline of
* the source range becomes visible on the destination node
* after all other transferred data in the source range has
* become visible on the destination
*
* Return:
* Upon successful completion, scif_readfrom() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned.
*
* Errors:
* EACCESS - Attempt to write to a read-only range
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - rma_flags is invalid
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - The range [loffset, loffset + len - 1] is invalid for the registered
* address space of epd, or, The range [roffset , roffset + len -1] is invalid
* for the registered address space of the peer of epd, or loffset or roffset
* is negative
*/
int scif_writeto(scif_epd_t epd, off_t loffset, size_t len, off_t
roffset, int rma_flags);

/**
* scif_vreadfrom() - Copy from a remote address space
* @epd: endpoint descriptor
* @addr: address to which to copy
* @len: length of range to copy
* @roffset: offset in remote registered address space
* from which to copy
* @rma_flags: transfer mode flags
*
* scif_vreadfrom() copies len bytes from the remote registered address
* space of the peer of endpoint epd, starting at the offset roffset, to local
* memory, starting at addr.
*
* The specified range [roffset, roffset + len - 1] must be within some
* registered window or windows of the remote nodes. The range may
* intersect multiple registered windows, but only if those windows are
* contiguous in the registered address space.
*
* If rma_flags includes SCIF_RMA_USECPU, then the data is copied using
* programmed read/writes. Otherwise the data is copied using DMA. If rma_-
* flags includes SCIF_RMA_SYNC, then scif_vreadfrom() will return after the
* transfer is complete. Otherwise, the transfer may be performed asynchron-
* ously. The order in which any two asynchronous RMA operations complete
* is non-deterministic. The synchronization functions, scif_fence_mark()/
* scif_fence_wait() and scif_fence_signal(), can be used to synchronize to
* the completion of asynchronous RMA operations on the same endpoint.
*
* The DMA transfer of individual bytes is not guaranteed to complete in
* address order. If rma_flags includes SCIF_RMA_ORDERED, then the last
* cacheline or partial cacheline of the source range will become visible on
* the destination node after all other transferred data in the source
* range has become visible on the destination node.
*
* If rma_flags includes SCIF_RMA_USECACHE, then the physical pages which back
* the specified local memory range may be remain in a pinned state even after
* the specified transfer completes. This may reduce overhead if some or all of
* the same virtual address range is referenced in a subsequent call of
* scif_vreadfrom() or scif_vwriteto().
*
* The optimal DMA performance will likely be realized if both
* addr and roffset are cacheline aligned (are a multiple of 64). Lower
* performance will likely be realized if addr and roffset are not
* cacheline aligned but are separated by some multiple of 64. The lowest level
* of performance is likely if addr and roffset are not separated by a
* multiple of 64.
*
* The rma_flags argument is formed by ORing together zero or more of the
* following values.
* SCIF_RMA_USECPU - perform the transfer using the CPU, otherwise use the DMA
* engine.
* SCIF_RMA_USECACHE - enable registration caching
* SCIF_RMA_SYNC - perform the transfer synchronously, returning after the
* transfer has completed. Passing this flag results in the
* current implementation busy waiting and consuming CPU cycles
* while the DMA transfer is in progress for best performance by
* avoiding the interrupt latency.
* SCIF_RMA_ORDERED - ensure that the last cacheline or partial cacheline of
* the source range becomes visible on the destination node
* after all other transferred data in the source range has
* become visible on the destination
*
* Return:
* Upon successful completion, scif_vreadfrom() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned.
*
* Errors:
* EACCESS - Attempt to write to a read-only range
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - rma_flags is invalid
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - Offsets in the range [roffset, roffset + len - 1] are invalid for the
* registered address space of epd
*/
int scif_vreadfrom(scif_epd_t epd, void *addr, size_t len, off_t roffset,
int rma_flags);

/**
* scif_vwriteto() - Copy to a remote address space
* @epd: endpoint descriptor
* @addr: address from which to copy
* @len: length of range to copy
* @roffset: offset in remote registered address space to
* which to copy
* @rma_flags: transfer mode flags
*
* scif_vwriteto() copies len bytes from the local memory, starting at addr, to
* the remote registered address space of the peer of endpoint epd, starting at
* the offset roffset.
*
* The specified range [roffset, roffset + len - 1] must be within some
* registered window or windows of the remote nodes. The range may intersect
* multiple registered windows, but only if those windows are contiguous in the
* registered address space.
*
* If rma_flags includes SCIF_RMA_USECPU, then the data is copied using
* programmed read/writes. Otherwise the data is copied using DMA. If rma_-
* flags includes SCIF_RMA_SYNC, then scif_vwriteto() will return after the
* transfer is complete. Otherwise, the transfer may be performed asynchron-
* ously. The order in which any two asynchronous RMA operations complete
* is non-deterministic. The synchronization functions, scif_fence_mark()/
* scif_fence_wait() and scif_fence_signal(), can be used to synchronize to
* the completion of asynchronous RMA operations on the same endpoint.
*
* The DMA transfer of individual bytes is not guaranteed to complete in
* address order. If rma_flags includes SCIF_RMA_ORDERED, then the last
* cacheline or partial cacheline of the source range will become visible on
* the destination node after all other transferred data in the source
* range has become visible on the destination node.
*
* If rma_flags includes SCIF_RMA_USECACHE, then the physical pages which back
* the specified local memory range may be remain in a pinned state even after
* the specified transfer completes. This may reduce overhead if some or all of
* the same virtual address range is referenced in a subsequent call of
* scif_vreadfrom() or scif_vwriteto().
*
* The optimal DMA performance will likely be realized if both
* addr and offset are cacheline aligned (are a multiple of 64). Lower
* performance will likely be realized if addr and offset are not cacheline
* aligned but are separated by some multiple of 64. The lowest level of
* performance is likely if addr and offset are not separated by a multiple of
* 64.
*
* The rma_flags argument is formed by ORing together zero or more of the
* following values.
* SCIF_RMA_USECPU - perform the transfer using the CPU, otherwise use the DMA
* engine.
* SCIF_RMA_USECACHE - allow registration caching
* SCIF_RMA_SYNC - perform the transfer synchronously, returning after the
* transfer has completed. Passing this flag results in the
* current implementation busy waiting and consuming CPU cycles
* while the DMA transfer is in progress for best performance by
* avoiding the interrupt latency.
* SCIF_RMA_ORDERED - ensure that the last cacheline or partial cacheline of
* the source range becomes visible on the destination node
* after all other transferred data in the source range has
* become visible on the destination
*
* Return:
* Upon successful completion, scif_vwriteto() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned.
*
* Errors:
* EACCESS - Attempt to write to a read-only range
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - rma_flags is invalid
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - Offsets in the range [roffset, roffset + len - 1] are invalid for the
* registered address space of epd
*/
int scif_vwriteto(scif_epd_t epd, void *addr, size_t len, off_t roffset,
int rma_flags);

/**
* scif_fence_mark() - Mark previously issued RMAs
* @epd: endpoint descriptor
* @flags: control flags
* @mark: marked value returned as output.
*
* scif_fence_mark() returns after marking the current set of all uncompleted
* RMAs initiated through the endpoint epd or the current set of all
* uncompleted RMAs initiated through the peer of endpoint epd. The RMAs are
* marked with a value returned at mark. The application may subsequently call
* scif_fence_wait(), passing the value returned at mark, to await completion
* of all RMAs so marked.
*
* The flags argument has exactly one of the following values.
* SCIF_FENCE_INIT_SELF - RMA operations initiated through endpoint
* epd are marked
* SCIF_FENCE_INIT_PEER - RMA operations initiated through the peer
* of endpoint epd are marked
*
* Return:
* Upon successful completion, scif_fence_mark() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - flags is invalid
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENOMEM - Insufficient kernel memory was available
*/
int scif_fence_mark(scif_epd_t epd, int flags, int *mark);

/**
* scif_fence_wait() - Wait for completion of marked RMAs
* @epd: endpoint descriptor
* @mark: mark request
*
* scif_fence_wait() returns after all RMAs marked with mark have completed.
* The value passed in mark must have been obtained in a previous call to
* scif_fence_mark().
*
* Return:
* Upon successful completion, scif_fence_wait() returns 0; otherwise in user
* mode -1 is returned and errno is set to indicate the error; in kernel mode
* the negative of one of the following errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENOMEM - Insufficient kernel memory was available
*/
int scif_fence_wait(scif_epd_t epd, int mark);

/**
* scif_fence_signal() - Request a memory update on completion of RMAs
* @epd: endpoint descriptor
* @loff: local offset
* @lval: local value to write to loffset
* @roff: remote offset
* @rval: remote value to write to roffset
* @flags: flags
*
* scif_fence_signal() returns after marking the current set of all uncompleted
* RMAs initiated through the endpoint epd or marking the current set of all
* uncompleted RMAs initiated through the peer of endpoint epd.
*
* If flags includes SCIF_SIGNAL_LOCAL, then on completion of the RMAs in the
* marked set, lval is written to memory at the address corresponding to offset
* loff in the local registered address space of epd. loff must be within a
* registered window. If flags includes SCIF_SIGNAL_REMOTE, then on completion
* of the RMAs in the marked set, rval is written to memory at the address
* corresponding to offset roff in the remote registered address space of epd.
* roff must be within a remote registered window of the peer of epd. Note
* that any specified offset must be DWORD (4 byte / 32 bit) aligned.
*
* The flags argument is formed by OR'ing together the following.
* Exactly one of the following values.
* SCIF_FENCE_INIT_SELF - RMA operations initiated through endpoint
* epd are marked
* SCIF_FENCE_INIT_PEER - RMA operations initiated through the peer
* of endpoint epd are marked
* One or more of the following values.
* SCIF_SIGNAL_LOCAL - On completion of the marked set of RMAs, write lval to
* memory at the address corresponding to offset loff in the local
* registered address space of epd.
* SCIF_SIGNAL_REMOTE - On completion of the marked set of RMAs, write rval to
* memory at the address corresponding to offset roff in the remote
* registered address space of epd.
*
* Return:
* Upon successful completion, scif_fence_signal() returns 0; otherwise in
* user mode -1 is returned and errno is set to indicate the error; in kernel
* mode the negative of one of the following errors is returned.
*
* Errors:
* EBADF, ENOTTY - epd is not a valid endpoint descriptor
* ECONNRESET - Connection reset by peer
* EINVAL - flags is invalid, or loff or roff are not DWORD aligned
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - loff is invalid for the registered address of epd, or roff is invalid
* for the registered address space, of the peer of epd
*/
int scif_fence_signal(scif_epd_t epd, off_t loff, u64 lval, off_t roff,
u64 rval, int flags);

/**
* scif_get_node_ids() - Return information about online nodes
* @nodes: array in which to return online node IDs
* @len: number of entries in the nodes array
* @self: address to place the node ID of the local node
*
* scif_get_node_ids() fills in the nodes array with up to len node IDs of the
* nodes in the SCIF network. If there is not enough space in nodes, as
* indicated by the len parameter, only len node IDs are returned in nodes. The
* return value of scif_get_node_ids() is the total number of nodes currently in
* the SCIF network. By checking the return value against the len parameter,
* the user may determine if enough space for nodes was allocated.
*
* The node ID of the local node is returned at self.
*
* Return:
* Upon successful completion, scif_get_node_ids() returns the actual number of
* online nodes in the SCIF network including 'self'; otherwise in user mode
* -1 is returned and errno is set to indicate the error; in kernel mode no
* errors are returned.
*/
int scif_get_node_ids(u16 *nodes, int len, u16 *self);

/**
* scif_pin_pages() - Pin a set of pages
* @addr: Virtual address of range to pin
* @len: Length of range to pin
* @prot_flags: Page protection flags
* @map_flags: Page classification flags
* @pinned_pages: Handle to pinned pages
*
* scif_pin_pages() pins (locks in physical memory) the physical pages which
* back the range of virtual address pages starting at addr and continuing for
* len bytes. addr and len are constrained to be multiples of the page size. A
* successful scif_pin_pages() call returns a handle to pinned_pages which may
* be used in subsequent calls to scif_register_pinned_pages().
*
* The pages will remain pinned as long as there is a reference against the
* scif_pinned_pages_t value returned by scif_pin_pages() and until
* scif_unpin_pages() is called, passing the scif_pinned_pages_t value. A
* reference is added to a scif_pinned_pages_t value each time a window is
* created by calling scif_register_pinned_pages() and passing the
* scif_pinned_pages_t value. A reference is removed from a
* scif_pinned_pages_t value each time such a window is deleted.
*
* Subsequent operations which change the memory pages to which virtual
* addresses are mapped (such as mmap(), munmap()) have no effect on the
* scif_pinned_pages_t value or windows created against it.
*
* If the process will fork(), it is recommended that the registered
* virtual address range be marked with MADV_DONTFORK. Doing so will prevent
* problems due to copy-on-write semantics.
*
* The prot_flags argument is formed by OR'ing together one or more of the
* following values.
* SCIF_PROT_READ - allow read operations against the pages
* SCIF_PROT_WRITE - allow write operations against the pages
* The map_flags argument can be set as SCIF_MAP_KERNEL to interpret addr as a
* kernel space address. By default, addr is interpreted as a user space
* address.
*
* Return:
* Upon successful completion, scif_pin_pages() returns 0; otherwise the
* negative of one of the following errors is returned.
*
* Errors:
* EINVAL - prot_flags is invalid, map_flags is invalid, or offset is negative
* ENOMEM - Not enough space
*/
int scif_pin_pages(void *addr, size_t len, int prot_flags, int map_flags,
scif_pinned_pages_t *pinned_pages);

/**
* scif_unpin_pages() - Unpin a set of pages
* @pinned_pages: Handle to pinned pages to be unpinned
*
* scif_unpin_pages() prevents scif_register_pinned_pages() from registering new
* windows against pinned_pages. The physical pages represented by pinned_pages
* will remain pinned until all windows previously registered against
* pinned_pages are deleted (the window is scif_unregister()'d and all
* references to the window are removed (see scif_unregister()).
*
* pinned_pages must have been obtain from a previous call to scif_pin_pages().
* After calling scif_unpin_pages(), it is an error to pass pinned_pages to
* scif_register_pinned_pages().
*
* Return:
* Upon successful completion, scif_unpin_pages() returns 0; otherwise the
* negative of one of the following errors is returned.
*
* Errors:
* EINVAL - pinned_pages is not valid
*/
int scif_unpin_pages(scif_pinned_pages_t pinned_pages);

/**
* scif_register_pinned_pages() - Mark a memory region for remote access.
* @epd: endpoint descriptor
* @pinned_pages: Handle to pinned pages
* @offset: Registered address space offset
* @map_flags: Flags which control where pages are mapped
*
* The scif_register_pinned_pages() function opens a window, a range of whole
* pages of the registered address space of the endpoint epd, starting at
* offset po. The value of po, further described below, is a function of the
* parameters offset and pinned_pages, and the value of map_flags. Each page of
* the window represents a corresponding physical memory page of the range
* represented by pinned_pages; the length of the window is the same as the
* length of range represented by pinned_pages. A successful
* scif_register_pinned_pages() call returns po as the return value.
*
* When SCIF_MAP_FIXED is set in the map_flags argument, po will be offset
* exactly, and offset is constrained to be a multiple of the page size. The
* mapping established by scif_register_pinned_pages() will not replace any
* existing registration; an error is returned if any page of the new window
* would intersect an existing window.
*
* When SCIF_MAP_FIXED is not set, the implementation uses offset in an
* implementation-defined manner to arrive at po. The po so chosen will be an
* area of the registered address space that the implementation deems suitable
* for a mapping of the required size. An offset value of 0 is interpreted as
* granting the implementation complete freedom in selecting po, subject to
* constraints described below. A non-zero value of offset is taken to be a
* suggestion of an offset near which the mapping should be placed. When the
* implementation selects a value for po, it does not replace any extant
* window. In all cases, po will be a multiple of the page size.
*
* The physical pages which are so represented by a window are available for
* access in calls to scif_get_pages(), scif_readfrom(), scif_writeto(),
* scif_vreadfrom(), and scif_vwriteto(). While a window is registered, the
* physical pages represented by the window will not be reused by the memory
* subsystem for any other purpose. Note that the same physical page may be
* represented by multiple windows.
*
* Windows created by scif_register_pinned_pages() are unregistered by
* scif_unregister().
*
* The map_flags argument can be set to SCIF_MAP_FIXED which interprets a
* fixed offset.
*
* Return:
* Upon successful completion, scif_register_pinned_pages() returns the offset
* at which the mapping was placed (po); otherwise the negative of one of the
* following errors is returned.
*
* Errors:
* EADDRINUSE - SCIF_MAP_FIXED is set in map_flags and pages in the new window
* would intersect an existing window
* EAGAIN - The mapping could not be performed due to lack of resources
* ECONNRESET - Connection reset by peer
* EINVAL - map_flags is invalid, or SCIF_MAP_FIXED is set in map_flags, and
* offset is not a multiple of the page size, or offset is negative
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOMEM - Not enough space
* ENOTCONN - The endpoint is not connected
*/
off_t scif_register_pinned_pages(scif_epd_t epd,
scif_pinned_pages_t pinned_pages,
off_t offset, int map_flags);

/**
* scif_get_pages() - Add references to remote registered pages
* @epd: endpoint descriptor
* @offset: remote registered offset
* @len: length of range of pages
* @pages: returned scif_range structure
*
* scif_get_pages() returns the addresses of the physical pages represented by
* those pages of the registered address space of the peer of epd, starting at
* offset and continuing for len bytes. offset and len are constrained to be
* multiples of the page size.
*
* All of the pages in the specified range [offset, offset + len - 1] must be
* within a single window of the registered address space of the peer of epd.
*
* The addresses are returned as a virtually contiguous array pointed to by the
* phys_addr component of the scif_range structure whose address is returned in
* pages. The nr_pages component of scif_range is the length of the array. The
* prot_flags component of scif_range holds the protection flag value passed
* when the pages were registered.
*
* Each physical page whose address is returned by scif_get_pages() remains
* available and will not be released for reuse until the scif_range structure
* is returned in a call to scif_put_pages(). The scif_range structure returned
* by scif_get_pages() must be unmodified.
*
* It is an error to call scif_close() on an endpoint on which a scif_range
* structure of that endpoint has not been returned to scif_put_pages().
*
* Return:
* Upon successful completion, scif_get_pages() returns 0; otherwise the
* negative of one of the following errors is returned.
* Errors:
* ECONNRESET - Connection reset by peer.
* EINVAL - offset is not a multiple of the page size, or offset is negative, or
* len is not a multiple of the page size
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
* ENXIO - Offsets in the range [offset, offset + len - 1] are invalid
* for the registered address space of the peer epd
*/
int scif_get_pages(scif_epd_t epd, off_t offset, size_t len,
struct scif_range **pages);

/**
* scif_put_pages() - Remove references from remote registered pages
* @pages: pages to be returned
*
* scif_put_pages() releases a scif_range structure previously obtained by
* calling scif_get_pages(). The physical pages represented by pages may
* be reused when the window which represented those pages is unregistered.
* Therefore, those pages must not be accessed after calling scif_put_pages().
*
* Return:
* Upon successful completion, scif_put_pages() returns 0; otherwise the
* negative of one of the following errors is returned.
* Errors:
* EINVAL - pages does not point to a valid scif_range structure, or
* the scif_range structure pointed to by pages was already returned
* ENODEV - The remote node is lost or existed, but is not currently in the
* network since it may have crashed
* ENOTCONN - The endpoint is not connected
*/
int scif_put_pages(struct scif_range *pages);

/**
* scif_client_register() - Register a SCIF client
* @client: client to be registered
*
* scif_client_register() registers a SCIF client. The probe() method
* of the client is called when SCIF peer devices come online and the
* remove() method is called when the peer devices disappear.
*
* Return:
* Upon successful completion, scif_client_register() returns a non-negative
* value. Otherwise the return value is the same as subsys_interface_register()
* in the kernel.
*/
int scif_client_register(struct scif_client *client);

/**
* scif_client_unregister() - Unregister a SCIF client
* @client: client to be unregistered
*
* scif_client_unregister() unregisters a SCIF client.
*
* Return:
* None
*/
void scif_client_unregister(struct scif_client *client);

#endif /* __SCIF_H__ */
Overall Contributors
Person Tokens Prop Commits CommitProp
Sudeep Dutt 559 83.93% 2 50.00%
Ashutosh Dixit 107 16.07% 2 50.00%
Total 666 100.00% 4 100.00%
Directory: include/linux

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Created with cregit.

Person	Tokens	Prop	Commits	CommitProp
Sudeep Dutt	559	83.93%	2	50.00%
Ashutosh Dixit	107	16.07%	2	50.00%
Total	666	100.00%	4	100.00%

cregit-Linux how code gets into the kernel

Release 4.12 include/linux/scif.h

Overall Contributors