crypto: Add a new type of crypto buffer for a single mbuf.

This is intended for use in KTLS transmit where each TLS record is
described by a single mbuf that is itself queued in the socket buffer.
Using the existing CRYPTO_BUF_MBUF would result in
bus_dmamap_load_crp() walking additional mbufs in the socket buffer
that are not relevant, but generating a S/G list that potentially
exceeds the limit of the tag (while also wasting CPU cycles).

Reviewed by:	markj
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D30136

1 files changed, 21 insertions, 1 deletions

diff --git a/sys/opencrypto/cryptodev.h b/sys/opencrypto/cryptodev.h
index 862ad1d4f6e5..1adc81f2e4d3 100644
--- a/sys/opencrypto/cryptodev.h
+++ b/sys/opencrypto/cryptodev.h
@@ -354,7 +354,8 @@ enum crypto_buffer_type {
 	CRYPTO_BUF_UIO,
 	CRYPTO_BUF_MBUF,
 	CRYPTO_BUF_VMPAGE,
-	CRYPTO_BUF_LAST = CRYPTO_BUF_VMPAGE
+	CRYPTO_BUF_SINGLE_MBUF,
+	CRYPTO_BUF_LAST = CRYPTO_BUF_SINGLE_MBUF
 };
 
 /*
@@ -481,6 +482,13 @@ _crypto_use_mbuf(struct crypto_buffer *cb, struct mbuf *m)
 }
 
 static __inline void
+_crypto_use_single_mbuf(struct crypto_buffer *cb, struct mbuf *m)
+{
+	cb->cb_mbuf = m;
+	cb->cb_type = CRYPTO_BUF_SINGLE_MBUF;
+}
+
+static __inline void
 _crypto_use_vmpage(struct crypto_buffer *cb, vm_page_t *pages, int len,
     int offset)
 {
@@ -510,6 +518,12 @@ crypto_use_mbuf(struct cryptop *crp, struct mbuf *m)
 }
 
 static __inline void
+crypto_use_single_mbuf(struct cryptop *crp, struct mbuf *m)
+{
+	_crypto_use_single_mbuf(&crp->crp_buf, m);
+}
+
+static __inline void
 crypto_use_vmpage(struct cryptop *crp, vm_page_t *pages, int len, int offset)
 {
 	_crypto_use_vmpage(&crp->crp_buf, pages, len, offset);
@@ -534,6 +548,12 @@ crypto_use_output_mbuf(struct cryptop *crp, struct mbuf *m)
 }
 
 static __inline void
+crypto_use_output_single_mbuf(struct cryptop *crp, struct mbuf *m)
+{
+	_crypto_use_single_mbuf(&crp->crp_obuf, m);
+}
+
+static __inline void
 crypto_use_output_vmpage(struct cryptop *crp, vm_page_t *pages, int len,
     int offset)
 {