[PATCH 19/26] cifs: Remove support for ITER_KVEC/BVEC/FOLIOQ from smb_extract_iter_to_rdma()

[Stefan Metzmacher]

Hi David,

in ksmbd-for-next smbdirect_map_sges_from_iter is also called
in the server from smb_direct_writev() =>
smbdirect_connection_send_iter() =>
smbdirect_connection_send_single_iter()

So we still need ITER_KVEC.

Thanks!
metze

Am 26.03.26 um 11:45 schrieb David Howells:
> netfslib now only presents an bvecq queue and an associated ITER_BVECQ
> iterator to the filesystem, so it isn't going to see ITER_KVEC, ITER_BVEC
> or ITER_FOLIOQ iterators.  So remove that code.
> 
> Signed-off-by: David Howells <dhowells at redhat.com>
> cc: Steve French <sfrench at samba.org>
> cc: Paulo Alcantara <pc at manguebit.org>
> cc: Shyam Prasad N <sprasad at microsoft.com>
> cc: Tom Talpey <tom at talpey.com>
> cc: linux-cifs at vger.kernel.org
> cc: netfs at lists.linux.dev
> cc: linux-fsdevel at vger.kernel.org
> ---
>   fs/smb/client/smbdirect.c | 165 --------------------------------------
>   1 file changed, 165 deletions(-)
> 
> diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c
> index f8a6be83db98..d9e026d5e9f9 100644
> --- a/fs/smb/client/smbdirect.c
> +++ b/fs/smb/client/smbdirect.c
> @@ -3142,162 +3142,6 @@ static bool smb_set_sge(struct smb_extract_to_rdma *rdma,
>   	return true;
>   }
>   
> -/*
> - * Extract page fragments from a BVEC-class iterator and add them to an RDMA
> - * element list.  The pages are not pinned.
> - */
> -static ssize_t smb_extract_bvec_to_rdma(struct iov_iter *iter,
> -					struct smb_extract_to_rdma *rdma,
> -					ssize_t maxsize)
> -{
> -	const struct bio_vec *bv = iter->bvec;
> -	unsigned long start = iter->iov_offset;
> -	unsigned int i;
> -	ssize_t ret = 0;
> -
> -	for (i = 0; i < iter->nr_segs; i++) {
> -		size_t off, len;
> -
> -		len = bv[i].bv_len;
> -		if (start >= len) {
> -			start -= len;
> -			continue;
> -		}
> -
> -		len = min_t(size_t, maxsize, len - start);
> -		off = bv[i].bv_offset + start;
> -
> -		if (!smb_set_sge(rdma, bv[i].bv_page, off, len))
> -			return -EIO;
> -
> -		ret += len;
> -		maxsize -= len;
> -		if (rdma->nr_sge >= rdma->max_sge || maxsize <= 0)
> -			break;
> -		start = 0;
> -	}
> -
> -	if (ret > 0)
> -		iov_iter_advance(iter, ret);
> -	return ret;
> -}
> -
> -/*
> - * Extract fragments from a KVEC-class iterator and add them to an RDMA list.
> - * This can deal with vmalloc'd buffers as well as kmalloc'd or static buffers.
> - * The pages are not pinned.
> - */
> -static ssize_t smb_extract_kvec_to_rdma(struct iov_iter *iter,
> -					struct smb_extract_to_rdma *rdma,
> -					ssize_t maxsize)
> -{
> -	const struct kvec *kv = iter->kvec;
> -	unsigned long start = iter->iov_offset;
> -	unsigned int i;
> -	ssize_t ret = 0;
> -
> -	for (i = 0; i < iter->nr_segs; i++) {
> -		struct page *page;
> -		unsigned long kaddr;
> -		size_t off, len, seg;
> -
> -		len = kv[i].iov_len;
> -		if (start >= len) {
> -			start -= len;
> -			continue;
> -		}
> -
> -		kaddr = (unsigned long)kv[i].iov_base + start;
> -		off = kaddr & ~PAGE_MASK;
> -		len = min_t(size_t, maxsize, len - start);
> -		kaddr &= PAGE_MASK;
> -
> -		maxsize -= len;
> -		do {
> -			seg = min_t(size_t, len, PAGE_SIZE - off);
> -
> -			if (is_vmalloc_or_module_addr((void *)kaddr))
> -				page = vmalloc_to_page((void *)kaddr);
> -			else
> -				page = virt_to_page((void *)kaddr);
> -
> -			if (!smb_set_sge(rdma, page, off, seg))
> -				return -EIO;
> -
> -			ret += seg;
> -			len -= seg;
> -			kaddr += PAGE_SIZE;
> -			off = 0;
> -		} while (len > 0 && rdma->nr_sge < rdma->max_sge);
> -
> -		if (rdma->nr_sge >= rdma->max_sge || maxsize <= 0)
> -			break;
> -		start = 0;
> -	}
> -
> -	if (ret > 0)
> -		iov_iter_advance(iter, ret);
> -	return ret;
> -}
> -
> -/*
> - * Extract folio fragments from a FOLIOQ-class iterator and add them to an RDMA
> - * list.  The folios are not pinned.
> - */
> -static ssize_t smb_extract_folioq_to_rdma(struct iov_iter *iter,
> -					  struct smb_extract_to_rdma *rdma,
> -					  ssize_t maxsize)
> -{
> -	const struct folio_queue *folioq = iter->folioq;
> -	unsigned int slot = iter->folioq_slot;
> -	ssize_t ret = 0;
> -	size_t offset = iter->iov_offset;
> -
> -	BUG_ON(!folioq);
> -
> -	if (slot >= folioq_nr_slots(folioq)) {
> -		folioq = folioq->next;
> -		if (WARN_ON_ONCE(!folioq))
> -			return -EIO;
> -		slot = 0;
> -	}
> -
> -	do {
> -		struct folio *folio = folioq_folio(folioq, slot);
> -		size_t fsize = folioq_folio_size(folioq, slot);
> -
> -		if (offset < fsize) {
> -			size_t part = umin(maxsize, fsize - offset);
> -
> -			if (!smb_set_sge(rdma, folio_page(folio, 0), offset, part))
> -				return -EIO;
> -
> -			offset += part;
> -			ret += part;
> -			maxsize -= part;
> -		}
> -
> -		if (offset >= fsize) {
> -			offset = 0;
> -			slot++;
> -			if (slot >= folioq_nr_slots(folioq)) {
> -				if (!folioq->next) {
> -					WARN_ON_ONCE(ret < iter->count);
> -					break;
> -				}
> -				folioq = folioq->next;
> -				slot = 0;
> -			}
> -		}
> -	} while (rdma->nr_sge < rdma->max_sge && maxsize > 0);
> -
> -	iter->folioq = folioq;
> -	iter->folioq_slot = slot;
> -	iter->iov_offset = offset;
> -	iter->count -= ret;
> -	return ret;
> -}
> -
>   /*
>    * Extract memory fragments from a BVECQ-class iterator and add them to an RDMA
>    * list.  The folios are not pinned.
> @@ -3373,15 +3217,6 @@ static ssize_t smb_extract_iter_to_rdma(struct iov_iter *iter, size_t len,
>   	int before = rdma->nr_sge;
>   
>   	switch (iov_iter_type(iter)) {
> -	case ITER_BVEC:
> -		ret = smb_extract_bvec_to_rdma(iter, rdma, len);
> -		break;
> -	case ITER_KVEC:
> -		ret = smb_extract_kvec_to_rdma(iter, rdma, len);
> -		break;
> -	case ITER_FOLIOQ:
> -		ret = smb_extract_folioq_to_rdma(iter, rdma, len);
> -		break;
>   	case ITER_BVECQ:
>   		ret = smb_extract_bvecq_to_rdma(iter, rdma, len);
>   		break;
>