cifs: Don't support ITER_XARRAY

There's now no need to support ITER_XARRAY in cifs as netfslib hands down
ITER_FOLIOQ instead - and that's simpler to use with iterate_and_advance()
as it doesn't hold the RCU read lock over the step function.

This is part of the process of phasing out ITER_XARRAY.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Tom Talpey <tom@talpey.com>
cc: Enzo Matsumiya <ematsumiya@suse.de>
cc: linux-cifs@vger.kernel.org
Link: https://lore.kernel.org/r/20240814203850.2240469-26-dhowells@redhat.com/ # v2
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/smb/client/cifsencrypt.c

@@ -25,54 +25,6 @@
 #include "../common/arc4.h"
 #include <crypto/aead.h>
 
-/*
- * Hash data from an XARRAY-type iterator.
- */
-static ssize_t cifs_shash_xarray(const struct iov_iter *iter, ssize_t maxsize,
-				 struct shash_desc *shash)
-{
-	struct folio *folios[16], *folio;
-	unsigned int nr, i, j, npages;
-	loff_t start = iter->xarray_start + iter->iov_offset;
-	pgoff_t last, index = start / PAGE_SIZE;
-	ssize_t ret = 0;
-	size_t len, offset, foffset;
-	void *p;
-
-	if (maxsize == 0)
-		return 0;
-
-	last = (start + maxsize - 1) / PAGE_SIZE;
-	do {
-		nr = xa_extract(iter->xarray, (void **)folios, index, last,
-				ARRAY_SIZE(folios), XA_PRESENT);
-		if (nr == 0)
-			return -EIO;
-
-		for (i = 0; i < nr; i++) {
-			folio = folios[i];
-			npages = folio_nr_pages(folio);
-			foffset = start - folio_pos(folio);
-			offset = foffset % PAGE_SIZE;
-			for (j = foffset / PAGE_SIZE; j < npages; j++) {
-				len = min_t(size_t, maxsize, PAGE_SIZE - offset);
-				p = kmap_local_page(folio_page(folio, j));
-				ret = crypto_shash_update(shash, p, len);
-				kunmap_local(p);
-				if (ret < 0)
-					return ret;
-				maxsize -= len;
-				if (maxsize <= 0)
-					return 0;
-				start += len;
-				offset = 0;
-				index++;
-			}
-		}
-	} while (nr == ARRAY_SIZE(folios));
-	return 0;
-}
-
 static size_t cifs_shash_step(void *iter_base, size_t progress, size_t len,
 			      void *priv, void *priv2)
 {
@@ -96,9 +48,6 @@ static int cifs_shash_iter(const struct iov_iter *iter, size_t maxsize,
 	struct iov_iter tmp_iter = *iter;
 	int err = -EIO;
 
-	if (iov_iter_type(iter) == ITER_XARRAY)
-		return cifs_shash_xarray(iter, maxsize, shash);
-
 	if (iterate_and_advance_kernel(&tmp_iter, maxsize, shash, &err,
 				       cifs_shash_step) != maxsize)
 		return err;

fs/smb/client/smbdirect.c

@@ -2584,52 +2584,6 @@ static ssize_t smb_extract_folioq_to_rdma(struct iov_iter *iter,
 	return ret;
 }
 
-/*
- * Extract folio fragments from an XARRAY-class iterator and add them to an
- * RDMA list.  The folios are not pinned.
- */
-static ssize_t smb_extract_xarray_to_rdma(struct iov_iter *iter,
-					  struct smb_extract_to_rdma *rdma,
-					  ssize_t maxsize)
-{
-	struct xarray *xa = iter->xarray;
-	struct folio *folio;
-	loff_t start = iter->xarray_start + iter->iov_offset;
-	pgoff_t index = start / PAGE_SIZE;
-	ssize_t ret = 0;
-	size_t off, len;
-	XA_STATE(xas, xa, index);
-
-	rcu_read_lock();
-
-	xas_for_each(&xas, folio, ULONG_MAX) {
-		if (xas_retry(&xas, folio))
-			continue;
-		if (WARN_ON(xa_is_value(folio)))
-			break;
-		if (WARN_ON(folio_test_hugetlb(folio)))
-			break;
-
-		off = offset_in_folio(folio, start);
-		len = min_t(size_t, maxsize, folio_size(folio) - off);
-
-		if (!smb_set_sge(rdma, folio_page(folio, 0), off, len)) {
-			rcu_read_unlock();
-			return -EIO;
-		}
-
-		maxsize -= len;
-		ret += len;
-		if (rdma->nr_sge >= rdma->max_sge || maxsize <= 0)
-			break;
-	}
-
-	rcu_read_unlock();
-	if (ret > 0)
-		iov_iter_advance(iter, ret);
-	return ret;
-}
-
 /*
  * Extract page fragments from up to the given amount of the source iterator
  * and build up an RDMA list that refers to all of those bits.  The RDMA list
@@ -2657,9 +2611,6 @@ static ssize_t smb_extract_iter_to_rdma(struct iov_iter *iter, size_t len,
 	case ITER_FOLIOQ:
 		ret = smb_extract_folioq_to_rdma(iter, rdma, len);
 		break;
-	case ITER_XARRAY:
-		ret = smb_extract_xarray_to_rdma(iter, rdma, len);
-		break;
 	default:
 		WARN_ON_ONCE(1);
 		return -EIO;