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authorDavid Howells <dhowells@redhat.com>2022-01-24 22:13:24 +0100
committerSteve French <stfrench@microsoft.com>2023-02-21 01:36:02 +0100
commitd08089f649a0cfb2099c8551ac47eef0cc23fdf2 (patch)
tree1165d72f35311d1017bf84c417cee6c37b3c01d9 /fs/cifs/smb2pdu.c
parentcifs: Add a function to read into an iter from a socket (diff)
downloadlinux-d08089f649a0cfb2099c8551ac47eef0cc23fdf2.tar.xz
linux-d08089f649a0cfb2099c8551ac47eef0cc23fdf2.zip
cifs: Change the I/O paths to use an iterator rather than a page list
Currently, the cifs I/O paths hand lists of pages from the VM interface routines at the top all the way through the intervening layers to the socket interface at the bottom. This is a problem, however, for interfacing with netfslib which passes an iterator through to the ->issue_read() method (and will pass an iterator through to the ->issue_write() method in future). Netfslib takes over bounce buffering for direct I/O, async I/O and encrypted content, so cifs doesn't need to do that. Netfslib also converts IOVEC-type iterators into BVEC-type iterators if necessary. Further, cifs needs foliating - and folios may come in a variety of sizes, so a page list pointing to an array of heterogeneous pages may cause problems in places such as where crypto is done. Change the cifs I/O paths to hand iov_iter iterators all the way through instead. Notes: (1) Some old routines are #if'd out to be removed in a follow up patch so as to avoid confusing diff, thereby making the diff output easier to follow. I've removed functions that don't overlap with anything added. (2) struct smb_rqst loses rq_pages, rq_offset, rq_npages, rq_pagesz and rq_tailsz which describe the pages forming the buffer; instead there's an rq_iter describing the source buffer and an rq_buffer which is used to hold the buffer for encryption. (3) struct cifs_readdata and cifs_writedata are similarly modified to smb_rqst. The ->read_into_pages() and ->copy_into_pages() are then replaced with passing the iterator directly to the socket. The iterators are stored in these structs so that they are persistent and don't get deallocated when the function returns (unlike if they were stack variables). (4) Buffered writeback is overhauled, borrowing the code from the afs filesystem to gather up contiguous runs of folios. The XARRAY-type iterator is then used to refer directly to the pagecache and can be passed to the socket to transmit data directly from there. This includes: cifs_extend_writeback() cifs_write_back_from_locked_folio() cifs_writepages_region() cifs_writepages() (5) Pages are converted to folios. (6) Direct I/O uses netfs_extract_user_iter() to create a BVEC-type iterator from an IOBUF/UBUF-type source iterator. (7) smb2_get_aead_req() uses netfs_extract_iter_to_sg() to extract page fragments from the iterator into the scatterlists that the crypto layer prefers. (8) smb2_init_transform_rq() attached pages to smb_rqst::rq_buffer, an xarray, to use as a bounce buffer for encryption. An XARRAY-type iterator can then be used to pass the bounce buffer to lower layers. 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: Paulo Alcantara <pc@cjr.nz> cc: Jeff Layton <jlayton@kernel.org> cc: linux-cifs@vger.kernel.org Link: https://lore.kernel.org/r/164311907995.2806745.400147335497304099.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/164928620163.457102.11602306234438271112.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165211420279.3154751.15923591172438186144.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165348880385.2106726.3220789453472800240.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/165364827111.3334034.934805882842932881.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/166126396180.708021.271013668175370826.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/166697259595.61150.5982032408321852414.stgit@warthog.procyon.org.uk/ # rfc Link: https://lore.kernel.org/r/166732031756.3186319.12528413619888902872.stgit@warthog.procyon.org.uk/ # rfc Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/smb2pdu.c')
-rw-r--r--fs/cifs/smb2pdu.c53
1 files changed, 17 insertions, 36 deletions
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 4982f5e65e13..0954fedfd1bc 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -4139,10 +4139,8 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
struct smbd_buffer_descriptor_v1 *v1;
bool need_invalidate = server->dialect == SMB30_PROT_ID;
- rdata->mr = smbd_register_mr(
- server->smbd_conn, rdata->pages,
- rdata->nr_pages, rdata->page_offset,
- rdata->tailsz, true, need_invalidate);
+ rdata->mr = smbd_register_mr(server->smbd_conn, &rdata->iter,
+ true, need_invalidate);
if (!rdata->mr)
return -EAGAIN;
@@ -4199,15 +4197,9 @@ smb2_readv_callback(struct mid_q_entry *mid)
(struct smb2_hdr *)rdata->iov[0].iov_base;
struct cifs_credits credits = { .value = 0, .instance = 0 };
struct smb_rqst rqst = { .rq_iov = &rdata->iov[1],
- .rq_nvec = 1, };
-
- if (rdata->got_bytes) {
- rqst.rq_pages = rdata->pages;
- rqst.rq_offset = rdata->page_offset;
- rqst.rq_npages = rdata->nr_pages;
- rqst.rq_pagesz = rdata->pagesz;
- rqst.rq_tailsz = rdata->tailsz;
- }
+ .rq_nvec = 1,
+ .rq_iter = rdata->iter,
+ .rq_iter_size = iov_iter_count(&rdata->iter), };
WARN_ONCE(rdata->server != mid->server,
"rdata server %p != mid server %p",
@@ -4225,6 +4217,8 @@ smb2_readv_callback(struct mid_q_entry *mid)
if (server->sign && !mid->decrypted) {
int rc;
+ iov_iter_revert(&rqst.rq_iter, rdata->got_bytes);
+ iov_iter_truncate(&rqst.rq_iter, rdata->got_bytes);
rc = smb2_verify_signature(&rqst, server);
if (rc)
cifs_tcon_dbg(VFS, "SMB signature verification returned error = %d\n",
@@ -4567,7 +4561,7 @@ smb2_async_writev(struct cifs_writedata *wdata,
req->VolatileFileId = io_parms->volatile_fid;
req->WriteChannelInfoOffset = 0;
req->WriteChannelInfoLength = 0;
- req->Channel = 0;
+ req->Channel = SMB2_CHANNEL_NONE;
req->Offset = cpu_to_le64(io_parms->offset);
req->DataOffset = cpu_to_le16(
offsetof(struct smb2_write_req, Buffer));
@@ -4587,26 +4581,18 @@ smb2_async_writev(struct cifs_writedata *wdata,
*/
if (smb3_use_rdma_offload(io_parms)) {
struct smbd_buffer_descriptor_v1 *v1;
+ size_t data_size = iov_iter_count(&wdata->iter);
bool need_invalidate = server->dialect == SMB30_PROT_ID;
- wdata->mr = smbd_register_mr(
- server->smbd_conn, wdata->pages,
- wdata->nr_pages, wdata->page_offset,
- wdata->tailsz, false, need_invalidate);
+ wdata->mr = smbd_register_mr(server->smbd_conn, &wdata->iter,
+ false, need_invalidate);
if (!wdata->mr) {
rc = -EAGAIN;
goto async_writev_out;
}
req->Length = 0;
req->DataOffset = 0;
- if (wdata->nr_pages > 1)
- req->RemainingBytes =
- cpu_to_le32(
- (wdata->nr_pages - 1) * wdata->pagesz -
- wdata->page_offset + wdata->tailsz
- );
- else
- req->RemainingBytes = cpu_to_le32(wdata->tailsz);
+ req->RemainingBytes = cpu_to_le32(data_size);
req->Channel = SMB2_CHANNEL_RDMA_V1_INVALIDATE;
if (need_invalidate)
req->Channel = SMB2_CHANNEL_RDMA_V1;
@@ -4625,19 +4611,14 @@ smb2_async_writev(struct cifs_writedata *wdata,
rqst.rq_iov = iov;
rqst.rq_nvec = 1;
- rqst.rq_pages = wdata->pages;
- rqst.rq_offset = wdata->page_offset;
- rqst.rq_npages = wdata->nr_pages;
- rqst.rq_pagesz = wdata->pagesz;
- rqst.rq_tailsz = wdata->tailsz;
+ rqst.rq_iter = wdata->iter;
+ rqst.rq_iter_size = iov_iter_count(&rqst.rq_iter);
#ifdef CONFIG_CIFS_SMB_DIRECT
- if (wdata->mr) {
+ if (wdata->mr)
iov[0].iov_len += sizeof(struct smbd_buffer_descriptor_v1);
- rqst.rq_npages = 0;
- }
#endif
- cifs_dbg(FYI, "async write at %llu %u bytes\n",
- io_parms->offset, io_parms->length);
+ cifs_dbg(FYI, "async write at %llu %u bytes iter=%zx\n",
+ io_parms->offset, io_parms->length, iov_iter_count(&rqst.rq_iter));
#ifdef CONFIG_CIFS_SMB_DIRECT
/* For RDMA read, I/O size is in RemainingBytes not in Length */