libceph: make recv path in secure mode work the same as send path

The recv path of secure mode is intertwined with that of crc mode.
While it's slightly more efficient that way (the ciphertext is read
into the destination buffer and decrypted in place, thus avoiding
two potentially heavy memory allocations for the bounce buffer and
the corresponding sg array), it isn't really amenable to changes.
Sacrifice that edge and align with the send path which always uses
a full-sized bounce buffer (currently there is no other way -- if
the kernel crypto API ever grows support for streaming (piecewise)
en/decryption for GCM [1], we would be able to easily take advantage
of that on both sides).

[1] https://lore.kernel.org/all/20141225202830.GA18794@gondor.apana.org.au/Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>

include/linux/ceph/messenger.h

@@ -383,6 +383,10 @@ struct ceph_connection_v2_info {
 	struct ceph_gcm_nonce in_gcm_nonce;
 	struct ceph_gcm_nonce out_gcm_nonce;
 
+	struct page **in_enc_pages;
+	int in_enc_page_cnt;
+	int in_enc_resid;
+	int in_enc_i;
 	struct page **out_enc_pages;
 	int out_enc_page_cnt;
 	int out_enc_resid;