afs: Eliminate afs_read

Now that directory and symlink reads go through netfslib, the afs_read
struct is mostly redundant with almost all data duplicated in the
netfs_io_request and netfs_io_subrequest structs that are also available
any time we're doing a fetch.

Eliminate afs_read by moving the one field we still need there to the
afs_call struct (we may be given a different amount of data than what we
asked for and have to track what remains of that) and using the
netfs_io_subrequest directly instead.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-24-dhowells@redhat.com
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

1 files changed, 26 insertions, 29 deletions

diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 784f7daab112..d9d224c95454 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -301,19 +301,19 @@ void afs_fs_fetch_status(struct afs_operation *op)
 static int afs_deliver_fs_fetch_data(struct afs_call *call)
 {
 	struct afs_operation *op = call->op;
+	struct netfs_io_subrequest *subreq = op->fetch.subreq;
 	struct afs_vnode_param *vp = &op->file[0];
-	struct afs_read *req = op->fetch.req;
 	const __be32 *bp;
 	size_t count_before;
 	int ret;
 
 	_enter("{%u,%zu,%zu/%llu}",
 	       call->unmarshall, call->iov_len, iov_iter_count(call->iter),
-	       req->actual_len);
+	       call->remaining);
 
 	switch (call->unmarshall) {
 	case 0:
-		req->actual_len = 0;
+		call->remaining = 0;
 		call->unmarshall++;
 		if (call->operation_ID == FSFETCHDATA64) {
 			afs_extract_to_tmp64(call);
@@ -323,8 +323,8 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
 		}
 		fallthrough;
 
-		/* Extract the returned data length into
-		 * ->actual_len.  This may indicate more or less data than was
+		/* Extract the returned data length into ->remaining.
+		 * This may indicate more or less data than was
 		 * requested will be returned.
 		 */
 	case 1:
@@ -333,42 +333,41 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
 		if (ret < 0)
 			return ret;
 
-		req->actual_len = be64_to_cpu(call->tmp64);
-		_debug("DATA length: %llu", req->actual_len);
+		call->remaining = be64_to_cpu(call->tmp64);
+		_debug("DATA length: %llu", call->remaining);
 
-		if (req->actual_len == 0)
+		if (call->remaining == 0)
 			goto no_more_data;
 
-		call->iter = req->iter;
-		call->iov_len = min(req->actual_len, req->len);
+		call->iter = &subreq->io_iter;
+		call->iov_len = umin(call->remaining, subreq->len - subreq->transferred);
 		call->unmarshall++;
 		fallthrough;
 
 		/* extract the returned data */
 	case 2:
 		count_before = call->iov_len;
-		_debug("extract data %zu/%llu", count_before, req->actual_len);
+		_debug("extract data %zu/%llu", count_before, call->remaining);
 
 		ret = afs_extract_data(call, true);
-		if (req->subreq) {
-			req->subreq->transferred += count_before - call->iov_len;
-			netfs_read_subreq_progress(req->subreq);
-		}
+		subreq->transferred += count_before - call->iov_len;
+		call->remaining -= count_before - call->iov_len;
+		netfs_read_subreq_progress(subreq);
 		if (ret < 0)
 			return ret;
 
 		call->iter = &call->def_iter;
-		if (req->actual_len <= req->len)
+		if (call->remaining)
 			goto no_more_data;
 
 		/* Discard any excess data the server gave us */
-		afs_extract_discard(call, req->actual_len - req->len);
+		afs_extract_discard(call, call->remaining);
 		call->unmarshall = 3;
 		fallthrough;
 
 	case 3:
 		_debug("extract discard %zu/%llu",
-		       iov_iter_count(call->iter), req->actual_len - req->len);
+		       iov_iter_count(call->iter), call->remaining);
 
 		ret = afs_extract_data(call, true);
 		if (ret < 0)
@@ -390,8 +389,8 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
 		xdr_decode_AFSCallBack(&bp, call, &vp->scb);
 		xdr_decode_AFSVolSync(&bp, &op->volsync);
 
-		req->data_version = vp->scb.status.data_version;
-		req->file_size = vp->scb.status.size;
+		if (subreq->start + subreq->transferred >= vp->scb.status.size)
+			__set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags);
 
 		call->unmarshall++;
 		fallthrough;
@@ -426,8 +425,8 @@ static const struct afs_call_type afs_RXFSFetchData64 = {
  */
 static void afs_fs_fetch_data64(struct afs_operation *op)
 {
+	struct netfs_io_subrequest *subreq = op->fetch.subreq;
 	struct afs_vnode_param *vp = &op->file[0];
-	struct afs_read *req = op->fetch.req;
 	struct afs_call *call;
 	__be32 *bp;
 
@@ -443,10 +442,10 @@ static void afs_fs_fetch_data64(struct afs_operation *op)
 	bp[1] = htonl(vp->fid.vid);
 	bp[2] = htonl(vp->fid.vnode);
 	bp[3] = htonl(vp->fid.unique);
-	bp[4] = htonl(upper_32_bits(req->pos));
-	bp[5] = htonl(lower_32_bits(req->pos));
+	bp[4] = htonl(upper_32_bits(subreq->start + subreq->transferred));
+	bp[5] = htonl(lower_32_bits(subreq->start + subreq->transferred));
 	bp[6] = 0;
-	bp[7] = htonl(lower_32_bits(req->len));
+	bp[7] = htonl(lower_32_bits(subreq->len   - subreq->transferred));
 
 	call->fid = vp->fid;
 	trace_afs_make_fs_call(call, &vp->fid);
@@ -458,9 +457,9 @@ static void afs_fs_fetch_data64(struct afs_operation *op)
  */
 void afs_fs_fetch_data(struct afs_operation *op)
 {
+	struct netfs_io_subrequest *subreq = op->fetch.subreq;
 	struct afs_vnode_param *vp = &op->file[0];
 	struct afs_call *call;
-	struct afs_read *req = op->fetch.req;
 	__be32 *bp;
 
 	if (test_bit(AFS_SERVER_FL_HAS_FS64, &op->server->flags))
@@ -472,16 +471,14 @@ void afs_fs_fetch_data(struct afs_operation *op)
 	if (!call)
 		return afs_op_nomem(op);
 
-	req->call_debug_id = call->debug_id;
-
 	/* marshall the parameters */
 	bp = call->request;
 	bp[0] = htonl(FSFETCHDATA);
 	bp[1] = htonl(vp->fid.vid);
 	bp[2] = htonl(vp->fid.vnode);
 	bp[3] = htonl(vp->fid.unique);
-	bp[4] = htonl(lower_32_bits(req->pos));
-	bp[5] = htonl(lower_32_bits(req->len));
+	bp[4] = htonl(lower_32_bits(subreq->start + subreq->transferred));
+	bp[5] = htonl(lower_32_bits(subreq->len   + subreq->transferred));
 
 	call->fid = vp->fid;
 	trace_afs_make_fs_call(call, &vp->fid);