scif_rma_list.c
/*
* Intel MIC Platform Software Stack (MPSS)
*
* Copyright(c) 2015 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, 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.
*
* Intel SCIF driver.
*
*/
#include "scif_main.h"
#include <linux/mmu_notifier.h>
#include <linux/highmem.h>
/*
* scif_insert_tcw:
*
* Insert a temp window to the temp registration list sorted by va_for_temp.
* RMA lock must be held.
*/
void scif_insert_tcw(struct scif_window *window, struct list_head *head)
{
struct scif_window *curr = NULL;
struct scif_window *prev = list_entry(head, struct scif_window, list);
struct list_head *item;
INIT_LIST_HEAD(&window->list);
/* Compare with tail and if the entry is new tail add it to the end */
if (!list_empty(head)) {
curr = list_entry(head->prev, struct scif_window, list);
if (curr->va_for_temp < window->va_for_temp) {
list_add_tail(&window->list, head);
return;
}
}
list_for_each(item, head) {
curr = list_entry(item, struct scif_window, list);
if (curr->va_for_temp > window->va_for_temp)
break;
prev = curr;
}
list_add(&window->list, &prev->list);
}
/*
* scif_insert_window:
*
* Insert a window to the self registration list sorted by offset.
* RMA lock must be held.
*/
void scif_insert_window(struct scif_window *window, struct list_head *head)
{
struct scif_window *curr = NULL, *prev = NULL;
struct list_head *item;
INIT_LIST_HEAD(&window->list);
list_for_each(item, head) {
curr = list_entry(item, struct scif_window, list);
if (curr->offset > window->offset)
break;
prev = curr;
}
if (!prev)
list_add(&window->list, head);
else
list_add(&window->list, &prev->list);
scif_set_window_ref(window, window->nr_pages);
}
/*
* scif_query_tcw:
*
* Query the temp cached registration list of ep for an overlapping window
* in case of permission mismatch, destroy the previous window. if permissions
* match and overlap is partial, destroy the window but return the new range
* RMA lock must be held.
*/
int scif_query_tcw(struct scif_endpt *ep, struct scif_rma_req *req)
{
struct list_head *item, *temp, *head = req->head;
struct scif_window *window;
u64 start_va_window, start_va_req = req->va_for_temp;
u64 end_va_window, end_va_req = start_va_req + req->nr_bytes;
if (!req->nr_bytes)
return -EINVAL;
/*
* Avoid traversing the entire list to find out that there
* is no entry that matches
*/
if (!list_empty(head)) {
window = list_last_entry(head, struct scif_window, list);
end_va_window = window->va_for_temp +
(window->nr_pages << PAGE_SHIFT);
if (start_va_req > end_va_window)
return -ENXIO;
}
list_for_each_safe(item, temp, head) {
window = list_entry(item, struct scif_window, list);
start_va_window = window->va_for_temp;
end_va_window = window->va_for_temp +
(window->nr_pages << PAGE_SHIFT);
if (start_va_req < start_va_window &&
end_va_req < start_va_window)
break;
if (start_va_req >= end_va_window)
continue;
if ((window->prot & req->prot) == req->prot) {
if (start_va_req >= start_va_window &&
end_va_req <= end_va_window) {
*req->out_window = window;
return 0;
}
/* expand window */
if (start_va_req < start_va_window) {
req->nr_bytes +=
start_va_window - start_va_req;
req->va_for_temp = start_va_window;
}
if (end_va_req >= end_va_window)
req->nr_bytes += end_va_window - end_va_req;
}
/* Destroy the old window to create a new one */
__scif_rma_destroy_tcw_helper(window);
break;
}
return -ENXIO;
}
/*
* scif_query_window:
*
* Query the registration list and check if a valid contiguous
* range of windows exist.
* RMA lock must be held.
*/
int scif_query_window(struct scif_rma_req *req)
{
struct list_head *item;
struct scif_window *window;
s64 end_offset, offset = req->offset;
u64 tmp_min, nr_bytes_left = req->nr_bytes;
if (!req->nr_bytes)
return -EINVAL;
list_for_each(item, req->head) {
window = list_entry(item, struct scif_window, list);
end_offset = window->offset +
(window->nr_pages << PAGE_SHIFT);
if (offset < window->offset)
/* Offset not found! */
return -ENXIO;
if (offset >= end_offset)
continue;
/* Check read/write protections. */
if ((window->prot & req->prot) != req->prot)
return -EPERM;
if (nr_bytes_left == req->nr_bytes)
/* Store the first window */
*req->out_window = window;
tmp_min = min((u64)end_offset - offset, nr_bytes_left);
nr_bytes_left -= tmp_min;
offset += tmp_min;
/*
* Range requested encompasses
* multiple windows contiguously.
*/
if (!nr_bytes_left) {
/* Done for partial window */
if (req->type == SCIF_WINDOW_PARTIAL ||
req->type == SCIF_WINDOW_SINGLE)
return 0;
/* Extra logic for full windows */
if (offset == end_offset)
/* Spanning multiple whole windows */
return 0;
/* Not spanning multiple whole windows */
return -ENXIO;
}
if (req->type == SCIF_WINDOW_SINGLE)
break;
}
dev_err(scif_info.mdev.this_device,
"%s %d ENXIO\n", __func__, __LINE__);
return -ENXIO;
}
/*
* scif_rma_list_unregister:
*
* Traverse the self registration list starting from window:
* 1) Call scif_unregister_window(..)
* RMA lock must be held.
*/
int scif_rma_list_unregister(struct scif_window *window,
s64 offset, int nr_pages)
{
struct scif_endpt *ep = (struct scif_endpt *)window->ep;
struct list_head *head = &ep->rma_info.reg_list;
s64 end_offset;
int err = 0;
int loop_nr_pages;
struct scif_window *_window;
list_for_each_entry_safe_from(window, _window, head, list) {
end_offset = window->offset + (window->nr_pages << PAGE_SHIFT);
loop_nr_pages = min((int)((end_offset - offset) >> PAGE_SHIFT),
nr_pages);
err = scif_unregister_window(window);
if (err)
return err;
nr_pages -= loop_nr_pages;
offset += (loop_nr_pages << PAGE_SHIFT);
if (!nr_pages)
break;
}
return 0;
}
/*
* scif_unmap_all_window:
*
* Traverse all the windows in the self registration list and:
* 1) Delete any DMA mappings created
*/
void scif_unmap_all_windows(scif_epd_t epd)
{
struct list_head *item, *tmp;
struct scif_window *window;
struct scif_endpt *ep = (struct scif_endpt *)epd;
struct list_head *head = &ep->rma_info.reg_list;
mutex_lock(&ep->rma_info.rma_lock);
list_for_each_safe(item, tmp, head) {
window = list_entry(item, struct scif_window, list);
scif_unmap_window(ep->remote_dev, window);
}
mutex_unlock(&ep->rma_info.rma_lock);
}
/*
* scif_unregister_all_window:
*
* Traverse all the windows in the self registration list and:
* 1) Call scif_unregister_window(..)
* RMA lock must be held.
*/
int scif_unregister_all_windows(scif_epd_t epd)
{
struct list_head *item, *tmp;
struct scif_window *window;
struct scif_endpt *ep = (struct scif_endpt *)epd;
struct list_head *head = &ep->rma_info.reg_list;
int err = 0;
mutex_lock(&ep->rma_info.rma_lock);
retry:
item = NULL;
tmp = NULL;
list_for_each_safe(item, tmp, head) {
window = list_entry(item, struct scif_window, list);
ep->rma_info.async_list_del = 0;
err = scif_unregister_window(window);
if (err)
dev_err(scif_info.mdev.this_device,
"%s %d err %d\n",
__func__, __LINE__, err);
/*
* Need to restart list traversal if there has been
* an asynchronous list entry deletion.
*/
if (READ_ONCE(ep->rma_info.async_list_del))
goto retry;
}
mutex_unlock(&ep->rma_info.rma_lock);
if (!list_empty(&ep->rma_info.mmn_list)) {
spin_lock(&scif_info.rmalock);
list_add_tail(&ep->mmu_list, &scif_info.mmu_notif_cleanup);
spin_unlock(&scif_info.rmalock);
schedule_work(&scif_info.mmu_notif_work);
}
return err;
}