[RFC 13/13] cifs: DIO to/from KVEC-type iterators should now work

From: David Howells <dhowells@redhat.com>
To: Steve French <smfrench@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Shyam Prasad N <nspmangalore@gmail.com>,
	Rohith Surabattula <rohiths.msft@gmail.com>,
	Tom Talpey <tom@talpey.com>, Stefan Metzmacher <metze@samba.org>,
	Christoph Hellwig <hch@infradead.org>,
	Matthew Wilcox <willy@infradead.org>,
	Jeff Layton <jlayton@kernel.org>,
	linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, Steve French <sfrench@samba.org>
Subject: [RFC 13/13] cifs: DIO to/from KVEC-type iterators should now work
Date: Wed, 25 Jan 2023 21:45:43 +0000	[thread overview]
Message-ID: <20230125214543.2337639-14-dhowells@redhat.com> (raw)
In-Reply-To: <20230125214543.2337639-1-dhowells@redhat.com>

DIO to/from KVEC-type iterators should now work as the iterator is passed
down to the socket in non-RDMA/non-crypto mode and in RDMA or crypto mode
care is taken to handle vmap/vmalloc correctly and not take page refs when
building a scatterlist.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Tom Talpey <tom@talpey.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
---
 fs/cifs/file.c | 20 --------------------
 1 file changed, 20 deletions(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 89d59723bda8..98d3ad86995d 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3545,16 +3545,6 @@ static ssize_t __cifs_writev(
 	struct cifs_aio_ctx *ctx;
 	int rc;
 
-	/*
-	 * iov_iter_get_pages_alloc doesn't work with ITER_KVEC.
-	 * In this case, fall back to non-direct write function.
-	 * this could be improved by getting pages directly in ITER_KVEC
-	 */
-	if (direct && iov_iter_is_kvec(from)) {
-		cifs_dbg(FYI, "use non-direct cifs_writev for kvec I/O\n");
-		direct = false;
-	}
-
 	rc = generic_write_checks(iocb, from);
 	if (rc <= 0)
 		return rc;
@@ -4088,16 +4078,6 @@ static ssize_t __cifs_readv(
 	loff_t offset = iocb->ki_pos;
 	struct cifs_aio_ctx *ctx;
 
-	/*
-	 * iov_iter_get_pages_alloc() doesn't work with ITER_KVEC,
-	 * fall back to data copy read path
-	 * this could be improved by getting pages directly in ITER_KVEC
-	 */
-	if (direct && iov_iter_is_kvec(to)) {
-		cifs_dbg(FYI, "use non-direct cifs_user_readv for kvec I/O\n");
-		direct = false;
-	}
-
 	len = iov_iter_count(to);
 	if (!len)
 		return 0;

