4 files changed, 124 insertions, 2 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 09522af227f17..b97692854966e 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -348,6 +348,13 @@ unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
 }
 EXPORT_SYMBOL(__bitmap_weight_and);
 
+unsigned int __bitmap_weight_andnot(const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	return BITMAP_WEIGHT(bitmap1[idx] & ~bitmap2[idx], bits);
+}
+EXPORT_SYMBOL(__bitmap_weight_andnot);
+
 void __bitmap_set(unsigned long *map, unsigned int start, int len)
 {
 	unsigned long *p = map + BIT_WORD(start);
diff --git a/lib/dynamic_queue_limits.c b/lib/dynamic_queue_limits.c
index fde0aa2441480..a1389db1c30a3 100644
--- a/lib/dynamic_queue_limits.c
+++ b/lib/dynamic_queue_limits.c
@@ -10,10 +10,77 @@
 #include <linux/dynamic_queue_limits.h>
 #include <linux/compiler.h>
 #include <linux/export.h>
+#include <trace/events/napi.h>
 
 #define POSDIFF(A, B) ((int)((A) - (B)) > 0 ? (A) - (B) : 0)
 #define AFTER_EQ(A, B) ((int)((A) - (B)) >= 0)
 
+static void dql_check_stall(struct dql *dql)
+{
+	unsigned short stall_thrs;
+	unsigned long now;
+
+	stall_thrs = READ_ONCE(dql->stall_thrs);
+	if (!stall_thrs)
+		return;
+
+	now = jiffies;
+	/* Check for a potential stall */
+	if (time_after_eq(now, dql->last_reap + stall_thrs)) {
+		unsigned long hist_head, t, start, end;
+
+		/* We are trying to detect a period of at least @stall_thrs
+		 * jiffies without any Tx completions, but during first half
+		 * of which some Tx was posted.
+		 */
+dqs_again:
+		hist_head = READ_ONCE(dql->history_head);
+		/* pairs with smp_wmb() in dql_queued() */
+		smp_rmb();
+
+		/* Get the previous entry in the ring buffer, which is the
+		 * oldest sample.
+		 */
+		start = (hist_head - DQL_HIST_LEN + 1) * BITS_PER_LONG;
+
+		/* Advance start to continue from the last reap time */
+		if (time_before(start, dql->last_reap + 1))
+			start = dql->last_reap + 1;
+
+		/* Newest sample we should have already seen a completion for */
+		end = hist_head * BITS_PER_LONG + (BITS_PER_LONG - 1);
+
+		/* Shrink the search space to [start, (now - start_thrs/2)] if
+		 * `end` is beyond the stall zone
+		 */
+		if (time_before(now, end + stall_thrs / 2))
+			end = now - stall_thrs / 2;
+
+		/* Search for the queued time in [t, end] */
+		for (t = start; time_before_eq(t, end); t++)
+			if (test_bit(t % (DQL_HIST_LEN * BITS_PER_LONG),
+				     dql->history))
+				break;
+
+		/* Variable t contains the time of the queue */
+		if (!time_before_eq(t, end))
+			goto no_stall;
+
+		/* The ring buffer was modified in the meantime, retry */
+		if (hist_head != READ_ONCE(dql->history_head))
+			goto dqs_again;
+
+		dql->stall_cnt++;
+		dql->stall_max = max_t(unsigned short, dql->stall_max, now - t);
+
+		trace_dql_stall_detected(dql->stall_thrs, now - t,
+					 dql->last_reap, dql->history_head,
+					 now, dql->history);
+	}
+no_stall:
+	dql->last_reap = now;
+}
+
 /* Records completed count and recalculates the queue limit */
 void dql_completed(struct dql *dql, unsigned int count)
 {
@@ -110,6 +177,8 @@ void dql_completed(struct dql *dql, unsigned int count)
 	dql->prev_last_obj_cnt = dql->last_obj_cnt;
 	dql->num_completed = completed;
 	dql->prev_num_queued = num_queued;
+
+	dql_check_stall(dql);
 }
 EXPORT_SYMBOL(dql_completed);
 
@@ -125,6 +194,10 @@ void dql_reset(struct dql *dql)
 	dql->prev_ovlimit = 0;
 	dql->lowest_slack = UINT_MAX;
 	dql->slack_start_time = jiffies;
+
+	dql->last_reap = jiffies;
+	dql->history_head = jiffies / BITS_PER_LONG;
+	memset(dql->history, 0, sizeof(dql->history));
 }
 EXPORT_SYMBOL(dql_reset);
 
@@ -133,6 +206,7 @@ void dql_init(struct dql *dql, unsigned int hold_time)
 	dql->max_limit = DQL_MAX_LIMIT;
 	dql->min_limit = 0;
 	dql->slack_hold_time = hold_time;
+	dql->stall_thrs = 0;
 	dql_reset(dql);
 }
 EXPORT_SYMBOL(dql_init);
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 65f22c2578b06..6b2b33579f565 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -380,6 +380,47 @@ static void __init test_replace(void)
 	expect_eq_bitmap(bmap, exp3_1_0, nbits);
 }
 
+static const unsigned long sg_mask[] __initconst = {
+	BITMAP_FROM_U64(0x000000000000035aULL),
+};
+
+static const unsigned long sg_src[] __initconst = {
+	BITMAP_FROM_U64(0x0000000000000667ULL),
+};
+
+static const unsigned long sg_gather_exp[] __initconst = {
+	BITMAP_FROM_U64(0x0000000000000029ULL),
+};
+
+static const unsigned long sg_scatter_exp[] __initconst = {
+	BITMAP_FROM_U64(0x000000000000021aULL),
+};
+
+static void __init test_bitmap_sg(void)
+{
+	unsigned int nbits = 64;
+	DECLARE_BITMAP(bmap_gather, 100);
+	DECLARE_BITMAP(bmap_scatter, 100);
+	DECLARE_BITMAP(bmap_tmp, 100);
+	DECLARE_BITMAP(bmap_res, 100);
+
+	/* Simple gather call */
+	bitmap_zero(bmap_gather, 100);
+	bitmap_gather(bmap_gather, sg_src, sg_mask, nbits);
+	expect_eq_bitmap(sg_gather_exp, bmap_gather, nbits);
+
+	/* Simple scatter call */
+	bitmap_zero(bmap_scatter, 100);
+	bitmap_scatter(bmap_scatter, sg_src, sg_mask, nbits);
+	expect_eq_bitmap(sg_scatter_exp, bmap_scatter, nbits);
+
+	/* Scatter/gather relationship */
+	bitmap_zero(bmap_tmp, 100);
+	bitmap_gather(bmap_tmp, bmap_scatter, sg_mask, nbits);
+	bitmap_scatter(bmap_res, bmap_tmp, sg_mask, nbits);
+	expect_eq_bitmap(bmap_scatter, bmap_res, nbits);
+}
+
 #define PARSE_TIME	0x1
 #define NO_LEN		0x2
 
@@ -1252,6 +1293,7 @@ static void __init selftest(void)
 	test_copy();
 	test_bitmap_region();
 	test_replace();
+	test_bitmap_sg();
 	test_bitmap_arr32();
 	test_bitmap_arr64();
 	test_bitmap_parse();
diff --git a/lib/test_blackhole_dev.c b/lib/test_blackhole_dev.c
index 4c40580a99a36..f247089d63c08 100644
--- a/lib/test_blackhole_dev.c
+++ b/lib/test_blackhole_dev.c
@@ -29,7 +29,6 @@ static int __init test_blackholedev_init(void)
 {
 	struct ipv6hdr *ip6h;
 	struct sk_buff *skb;
-	struct ethhdr *ethh;
 	struct udphdr *uh;
 	int data_len;
 	int ret;
@@ -61,7 +60,7 @@ static int __init test_blackholedev_init(void)
 	ip6h->saddr = in6addr_loopback;
 	ip6h->daddr = in6addr_loopback;
 	/* Ether */
-	ethh = (struct ethhdr *)skb_push(skb, sizeof(struct ethhdr));
+	skb_push(skb, sizeof(struct ethhdr));
 	skb_set_mac_header(skb, 0);
 
 	skb->protocol = htons(ETH_P_IPV6);