[KERNEL] convert to blk-mq and ktime

This converts the dnbd3 kernel module driver to use the blk-mq
infrastructure,  which allows the dnbd3 kernel module driver to be
compatible with Linux kernels in version 5.x or later. The conversion of
the implementation uses one hardware queue to preserve the existing
send/receive and load-balancing logic, but can be scaled up in the
future. In addition to that, time measurements in the implementation are
converted to ktime based accessors to replace the use of deprecated time
interfaces.

1 files changed, 18 insertions, 18 deletions

diff --git a/src/kernel/net.c b/src/kernel/net.c
index 9e48b86..337cfd7 100644
--- a/src/kernel/net.c
+++ b/src/kernel/net.c
@@ -25,13 +25,15 @@
 
 #include "serialize.h"
 
-#include <linux/time.h>
+#include <linux/ktime.h>
 #include <linux/signal.h>
 
 #ifndef MIN
 #define MIN(a,b) ((a) < (b) ? (a) : (b))
 #endif
 
+#define ktime_to_s(kt) ktime_divns(kt, NSEC_PER_SEC)
+
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 2, 0)
 #define dnbd3_sock_create(af,type,proto,sock) sock_create_kern(&init_net, (af) == HOST_IP4 ? AF_INET : AF_INET6, type, proto, sock)
 #else
@@ -203,8 +205,8 @@ int dnbd3_net_connect(dnbd3_device_t *dev)
 		if (dnbd3_sock_create(dev->cur_server.host.type, SOCK_STREAM, IPPROTO_TCP, &dev->sock) < 0)
 			error_dev("ERROR: Couldn't create socket (v6).");
 
-		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
-		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO_NEW, (char *)&timeout, sizeof(timeout));
+		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO_NEW, (char *)&timeout, sizeof(timeout));
 		dev->sock->sk->sk_allocation = GFP_NOIO;
 		if (dev->cur_server.host.type == HOST_IP4)
 		{
@@ -289,8 +291,8 @@ int dnbd3_net_connect(dnbd3_device_t *dev)
 		debug_dev("INFO: On-the-fly server change.");
 		dev->sock = dev->better_sock;
 		dev->better_sock = NULL;
-		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
-		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_SNDTIMEO_NEW, (char *)&timeout, sizeof(timeout));
+		kernel_setsockopt(dev->sock, SOL_SOCKET, SO_RCVTIMEO_NEW, (char *)&timeout, sizeof(timeout));
 	}
 
 	dev->panic = 0;
@@ -459,7 +461,7 @@ int dnbd3_net_discover(void *data)
 	uint64_t filesize;
 	uint16_t rid;
 
-	struct timeval start, end;
+	ktime_t start, end;
 	unsigned long rtt, best_rtt = 0;
 	unsigned long irqflags;
 	int i, j, isize, best_server, current_server;
@@ -565,7 +567,7 @@ int dnbd3_net_discover(void *data)
 		}
 		if (NUMBER_SERVERS > isize) {
 			for (i = 0; i < isize; ++i) {
-				j = ((start.tv_sec >> i) ^ (start.tv_usec >> j)) % NUMBER_SERVERS;
+				j = ((ktime_to_s(start) >> i) ^ (ktime_to_us(start) >> j)) % NUMBER_SERVERS;
 				if (j != i) {
 					mlen = check_order[i];
 					check_order[i] = check_order[j];
@@ -579,7 +581,7 @@ int dnbd3_net_discover(void *data)
 			i = check_order[j];
 			if (dev->alt_servers[i].host.type == 0) // Empty slot
 				continue;
-			if (!dev->panic && dev->alt_servers[i].failures > 50 && (start.tv_usec & 7) != 0) // If not in panic mode, skip server if it failed too many times
+			if (!dev->panic && dev->alt_servers[i].failures > 50 && (ktime_to_us(start) & 7) != 0) // If not in panic mode, skip server if it failed too many times
 				continue;
 			if (isize-- <= 0 && !is_same_server(&dev->cur_server, &dev->alt_servers[i]))
 				continue;
@@ -591,8 +593,8 @@ int dnbd3_net_discover(void *data)
 				sock = NULL;
 				continue;
 			}
-			kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
-			kernel_setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout, sizeof(timeout));
+			kernel_setsockopt(sock, SOL_SOCKET, SO_SNDTIMEO_NEW, (char *)&timeout, sizeof(timeout));
+			kernel_setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO_NEW, (char *)&timeout, sizeof(timeout));
 			sock->sk->sk_allocation = GFP_NOIO;
 			if (dev->alt_servers[i].host.type == HOST_IP4)
 			{
@@ -693,7 +695,7 @@ int dnbd3_net_discover(void *data)
 			iov[0].iov_len = sizeof(dnbd3_request);
 
 			// start rtt measurement
-			do_gettimeofday(&start);
+			start = ktime_get_real();
 
 			if (kernel_sendmsg(sock, &msg, iov, 1, sizeof(dnbd3_request)) <= 0)
 				error_alt("ERROR: Requesting test block failed (discover).");
@@ -715,10 +717,9 @@ int dnbd3_net_discover(void *data)
 			if (kernel_recvmsg(sock, &msg, iov, 1, dnbd3_reply.size, msg.msg_flags) != RTT_BLOCK_SIZE)
 				error_alt("ERROR: Receiving test block payload failed (discover).");
 
-			do_gettimeofday(&end); // end rtt measurement
+			end = ktime_get_real(); // end rtt measurement
 
-			dev->alt_servers[i].rtts[turn] = (unsigned long)((end.tv_sec - start.tv_sec) * 1000000ull
-			   + (end.tv_usec - start.tv_usec));
+			dev->alt_servers[i].rtts[turn] = (unsigned long) ktime_us_delta(end, start);
 
 			rtt = (dev->alt_servers[i].rtts[0] + dev->alt_servers[i].rtts[1] + dev->alt_servers[i].rtts[2]
 			   + dev->alt_servers[i].rtts[3]) / 4;
@@ -781,7 +782,7 @@ int dnbd3_net_discover(void *data)
 			continue;
 		}
 
-		do_change = ready && best_server != current_server && (start.tv_usec & 3) != 0
+		do_change = ready && best_server != current_server && (ktime_to_us(start) & 3) != 0
 				   && RTT_THRESHOLD_FACTOR(dev->cur_rtt) > best_rtt + 1500;
 
 		if (ready && !do_change) {
@@ -823,7 +824,7 @@ int dnbd3_net_discover(void *data)
 			best_sock = NULL;
 		}
 
-		if (!ready || (start.tv_usec & 15) != 0)
+		if (!ready || (ktime_to_us(start) & 15) != 0)
 			turn = (turn + 1) % 4;
 		if (turn == 2) // Set ready when we only have 2 of 4 measurements for quicker load balancing
 			ready = 1;
@@ -1032,7 +1033,7 @@ int dnbd3_net_receive(void *data)
 			}
 			spin_lock_irqsave(&dev->blk_lock, irqflags);
 			list_del_init(&blk_request->queuelist);
-			__blk_end_request_all(blk_request, 0);
+			blk_mq_end_request(blk_request, BLK_STS_OK);
 			spin_unlock_irqrestore(&dev->blk_lock, irqflags);
 			continue;
 
@@ -1120,4 +1121,3 @@ int dnbd3_net_receive(void *data)
 	dev->thread_receive = NULL;
 	return -1;
 }
-