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/*
* mq.c
*
* Created on: Jun 26, 2019
* Author: fred
*/
#include <net/sock.h>
#include "mq.h"
#include "block.h"
#define DNBD3_CMD_REQUEUED 1
//static void dnbd3_config_put(struct dnbd3_device_t *dev)
//{
// if (refcount_dec_and_mutex_lock(&dev->config_refs,
// &dev->config_lock)) {
//
// dev->tag_set.timeout = 0;
// dev->disk->queue->limits.discard_granularity = 0;
// dev->disk->queue->limits.discard_alignment = 0;
// blk_queue_max_discard_sectors(dev->disk->queue, UINT_MAX);
// blk_queue_flag_clear(QUEUE_FLAG_DISCARD, dev->disk->queue);
//
// mutex_unlock(&dev->config_lock);
// nbd_put(dev);
// module_put(THIS_MODULE);
// }
//}
#define dnbd3_priv_to_cmd(req) ((req)->cmd_flags >> REQ_FLAG_BITS)
static int dnbd3_send_cmd(struct dnbd3_device_t *dev, struct dnbd3_cmd *cmd, int index)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
dnbd3_request_t dnbd3_request;
dnbd3_reply_t dnbd3_reply;
struct msghdr msg;
struct kvec iov;
struct req_iterator iter;
struct bio_vec bvec_inst;
struct bio_vec *bvec = &bvec_inst;
sigset_t blocked, oldset;
void *kaddr;
int result;
init_msghdr(msg);
dnbd3_request.magic = dnbd3_packet_magic;
switch (req_op(req)) {
case REQ_OP_DISCARD:
printk(KERN_DEBUG "dnbd3: request operation discard on device %d\n", dev->minor);
break;
case REQ_OP_FLUSH:
printk(KERN_DEBUG "dnbd3: request operation flush on device %d\n", dev->minor);
break;
case REQ_OP_WRITE:
printk(KERN_DEBUG "dnbd3: request operation write on device %d\n", dev->minor);
break;
case REQ_OP_READ:
printk(KERN_DEBUG "dnbd3: request operation read on device %d\n", dev->minor);
dnbd3_request.cmd = CMD_GET_BLOCK;
dnbd3_request.offset = blk_rq_pos(req) << 9; // *512
dnbd3_request.size = blk_rq_bytes(req); // bytes left to complete entire request
break;
case REQ_OP_DRV_IN:
printk(KERN_DEBUG "dnbd3: request operation driver in on device %d\n", dev->minor);
dnbd3_request.cmd = dnbd3_priv_to_cmd(req);
dnbd3_request.size = 0;
break;
default:
return -EIO;
}
dnbd3_request.handle = (uint64_t)(uintptr_t)req; // Double cast to prevent warning on 32bit
fixup_request(dnbd3_request);
iov.iov_base = &dnbd3_request;
iov.iov_len = sizeof(dnbd3_request);
if (kernel_sendmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_request)) != sizeof(dnbd3_request)) {
printk(KERN_ERR "dnbd3: connection to server lost\n");
result = -EAGAIN;
goto error;
}
// receive net reply
iov.iov_base = &dnbd3_reply;
iov.iov_len = sizeof(dnbd3_reply);
result = kernel_recvmsg(dev->sock, &msg, &iov, 1, sizeof(dnbd3_reply), msg.msg_flags);
if (!result) {
printk(KERN_ERR "dnbd3: connection to server lost\n");
result = -EIO;
goto error;
}
fixup_reply(dnbd3_reply);
// check error
if (dnbd3_reply.magic != dnbd3_packet_magic) {
printk(KERN_ERR "dnbd3: wrong magic packet\n");
result = -EIO;
goto error;
}
// if (dnbd3_reply.cmd == 0) {
// printk(KERN_ERR "dnbd3: command was 0\n");
// result = -EIO;
// goto error;
// }
if (dnbd3_reply.cmd != CMD_GET_BLOCK) {
printk(KERN_ERR "dnbd3: command was %d\n", dnbd3_reply.cmd);
result = -EIO;
goto error;
}
rq_for_each_segment(bvec_inst, req, iter) {
siginitsetinv(&blocked, sigmask(SIGKILL));
sigprocmask(SIG_SETMASK, &blocked, &oldset);
kaddr = kmap(bvec->bv_page) + bvec->bv_offset;
iov.iov_base = kaddr;
iov.iov_len = bvec->bv_len;
if (kernel_recvmsg(dev->sock, &msg, &iov, 1, bvec->bv_len, msg.msg_flags) != bvec->bv_len) {
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL );
printk(KERN_ERR "dnbd3: could not receive form net to block layer\n");
goto error;
}
kunmap(bvec->bv_page);
sigprocmask(SIG_SETMASK, &oldset, NULL );
}
//
// __blk_end_request_all(req, 0);
blk_mq_end_request(req, 0);
dev->pending = NULL;
error:
return result;
}
static void dnbd3_requeue_cmd(struct dnbd3_cmd *cmd)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
if (!test_and_set_bit(DNBD3_CMD_REQUEUED, &cmd->flags))
blk_mq_requeue_request(req, true);
}
static int dnbd3_handle_cmd(struct dnbd3_cmd *cmd, int index)
{
struct request *req = blk_mq_rq_from_pdu(cmd);
struct dnbd3_device_t *dev = cmd->dnbd3;
int ret = -1;
printk(KERN_DEBUG "dnbd3: handle request at position %lu and size %d, device %i\n", blk_rq_pos(req), blk_rq_bytes(req), dev->minor);
if (!refcount_inc_not_zero(&dev->config_refs)) {
dev_err_ratelimited(disk_to_dev(dev->disk), "socks array is empty\n");
blk_mq_start_request(req);
return -EINVAL;
}
if (index >= 1) { // TODO use next server with good rtt for this request
printk(KERN_INFO "dnbd3: index is %d", index);
dev_err_ratelimited(disk_to_dev(dev->disk), "attempted send on invalid socket\n");
// nbd_config_put(nbd);
// TODO what to do here?
blk_mq_start_request(req);
return -EINVAL;
}
cmd->status = BLK_STS_OK;
again:
mutex_lock(&dev->socket_lock);
if (!dev->sock) {
mutex_unlock(&dev->socket_lock);
printk(KERN_DEBUG "dnbd3: not connected, try to reconnect\n");
if (!dnbd3_net_connect(dev)) {
printk(KERN_ERR "dnbd3: failed to reconnect\n");
blk_mq_start_request(req);
return -EIO;
}
goto again;
}
blk_mq_start_request(req);
if (unlikely(dev->pending && dev->pending != req)) {
dnbd3_requeue_cmd(cmd);
ret = 0;
goto out;
}
ret = dnbd3_send_cmd(dev, cmd, index);
if (ret == -EAGAIN) {
dev_err_ratelimited(disk_to_dev(dev->disk), "request send failed, requeueing\n");
dnbd3_requeue_cmd(cmd);
ret = 0;
}
out:
mutex_unlock(&dev->socket_lock);
// nbd_config_put(nbd);
return ret;
}
static blk_status_t dnbd3_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd)
{
struct dnbd3_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
int ret;
struct dnbd3_device_t *dev = cmd->dnbd3;
printk(KERN_DEBUG "dnbd3: queue request device %i\n", dev->minor);
mutex_lock(&cmd->lock);
clear_bit(DNBD3_CMD_REQUEUED, &cmd->flags);
ret = dnbd3_handle_cmd(cmd, hctx->queue_num);
if (ret < 0)
ret = BLK_STS_IOERR;
else if (!ret)
ret = BLK_STS_OK;
mutex_unlock(&cmd->lock);
return ret;
}
static void dnbd3_complete_rq(struct request *req)
{
printk(KERN_DEBUG "dnbd3: dnbd3_complete_rq\n");
}
static int dnbd3_init_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx, unsigned int numa_node)
{
struct dnbd3_cmd *cmd = blk_mq_rq_to_pdu(rq);
cmd->dnbd3 = set->driver_data;
cmd->flags = 0;
mutex_init(&cmd->lock);
return 0;
}
static enum blk_eh_timer_return dnbd3_xmit_timeout(struct request *req, bool reserved)
{
printk(KERN_DEBUG "dnbd3: dnbd3_xmit_timeout\n");
return BLK_EH_DONE;
}
struct blk_mq_ops dnbd3_mq_ops = {
.queue_rq = dnbd3_queue_rq,
.complete = dnbd3_complete_rq,
.init_request = dnbd3_init_request,
.timeout = dnbd3_xmit_timeout,
};
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