dm crypt: use unbound workqueue for request processing

Use unbound workqueue by default so that work is automatically balanced
between available CPUs.  The original behavior of encrypting using the
same cpu that IO was submitted on can still be enabled by setting the
optional 'same_cpu_crypt' table argument.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 34 insertions, 15 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 08981be..5063c90 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -108,7 +108,7 @@ struct iv_tcw_private {
  * Crypt: maps a linear range of a block device
  * and encrypts / decrypts at the same time.
  */
-enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
+enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID, DM_CRYPT_SAME_CPU };
 
 /*
  * The fields in here must be read only after initialization.
@@ -1688,7 +1688,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	char dummy;
 
 	static struct dm_arg _args[] = {
-		{0, 1, "Invalid number of feature args"},
+		{0, 2, "Invalid number of feature args"},
 	};
 
 	if (argc < 5) {
@@ -1788,15 +1788,23 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		if (ret)
 			goto bad;
 
-		opt_string = dm_shift_arg(&as);
+		while (opt_params--) {
+			opt_string = dm_shift_arg(&as);
+			if (!opt_string) {
+				ti->error = "Not enough feature arguments";
+				goto bad;
+			}
 
-		if (opt_params == 1 && opt_string &&
-		    !strcasecmp(opt_string, "allow_discards"))
-			ti->num_discard_bios = 1;
-		else if (opt_params) {
-			ret = -EINVAL;
-			ti->error = "Invalid feature arguments";
-			goto bad;
+			if (!strcasecmp(opt_string, "allow_discards"))
+				ti->num_discard_bios = 1;
+
+			else if (!strcasecmp(opt_string, "same_cpu_crypt"))
+				set_bit(DM_CRYPT_SAME_CPU, &cc->flags);
+
+			else {
+				ti->error = "Invalid feature arguments";
+				goto bad;
+			}
 		}
 	}
 
@@ -1807,8 +1815,11 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
-	cc->crypt_queue = alloc_workqueue("kcryptd",
-					  WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
+	if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
+		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
+	else
+		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
+						  num_online_cpus());
 	if (!cc->crypt_queue) {
 		ti->error = "Couldn't create kcryptd queue";
 		goto bad;
@@ -1860,6 +1871,7 @@ static void crypt_status(struct dm_target *ti, status_type_t type,
 {
 	struct crypt_config *cc = ti->private;
 	unsigned i, sz = 0;
+	int num_feature_args = 0;
 
 	switch (type) {
 	case STATUSTYPE_INFO:
@@ -1878,8 +1890,15 @@ static void crypt_status(struct dm_target *ti, status_type_t type,
 		DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
 				cc->dev->name, (unsigned long long)cc->start);
 
-		if (ti->num_discard_bios)
-			DMEMIT(" 1 allow_discards");
+		num_feature_args += !!ti->num_discard_bios;
+		num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags);
+		if (num_feature_args) {
+			DMEMIT(" %d", num_feature_args);
+			if (ti->num_discard_bios)
+				DMEMIT(" allow_discards");
+			if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
+				DMEMIT(" same_cpu_crypt");
+		}
 
 		break;
 	}
@@ -1976,7 +1995,7 @@ static int crypt_iterate_devices(struct dm_target *ti,
 
 static struct target_type crypt_target = {
 	.name   = "crypt",
-	.version = {1, 13, 0},
+	.version = {1, 14, 0},
 	.module = THIS_MODULE,
 	.ctr    = crypt_ctr,
 	.dtr    = crypt_dtr,