* [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning
@ 2023-02-10 23:31 David Howells
2023-02-10 23:31 ` [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
` (10 more replies)
0 siblings, 11 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:31 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel
Hi Steve,
Here's an updated version of my patchset to make the cifs/smb3 driver pass
iov_iters down to the lowest layers where they can be passed directly to
the network transport rather than passing lists of pages around.
I've dropped the patch Stefan Metzmacher objected to and the splice patch
and rebased on top of a merge of part of my iov-extract branch onto your
for-next branch. The merge is so that the same commits are used as are in
the linux-block tree. At the iov-extract-base tag point my branch makes
the following changes:
(1) Change how file read-splices are done, using ITER_BVEC (DIO read) or
page cache extraction (buffered read). ITER_PIPE is then removed.
(2) Add a function to replace iov_iter_get_pages*() that uses FOLL_PIN on
user pages (IOVEC, UBUF) and doesn't pin kernel pages (BVEC, KVEC,
XARRAY).
The series also deals with some other issues:
(*) By pinning pages, it fixes the race between concurrent DIO read and
fork, whereby the pages containing the DIO read buffer may end up
belonging to the child process and not the parent - with the result
that the parent might not see the retrieved data.
(*) cifs shouldn't take refs on pages extracted from non-user-backed
iterators (eg. KVEC). With these changes, cifs will apply the
appropriate cleanup. Note that there is the possibility the network
transport might, but that's beyond the scope of this patchset.
(*) Making it easier to transition to using folios in cifs rather than
pages by dealing with them through BVEC and XARRAY iterators.
The series starts with a couple of patches that add stuff to netfslib that
I want to use there as well as in cifs:
(1) Add a netfslib function to extract and pin pages from an ITER_IOBUF or
ITER_UBUF iterator into an ITER_BVEC iterator.
(2) Add a netfslib function to extract pages from an iterator that's of
type ITER_UBUF/IOVEC/BVEC/KVEC/XARRAY and add them to a scatterlist.
The cleanup will need to be done as for iov_iter_extract_pages().
BVEC, KVEC and XARRAY iterators can be rendered into elements that
span multiple pages.
Then a fix:
(3) Fix oops due to uncleared server->smbd_conn in reconnect
Then there are some cifs helpers that work with iterators:
(4) Add a function to walk through an ITER_BVEC/KVEC/XARRAY iterator and
add elements to an RDMA SGE list. Only the DMA addresses are stored,
and an element may span multiple pages (say if an xarray contains a
multipage folio).
(5) Add a function to walk through an ITER_BVEC/KVEC/XARRAY iterator and
pass the contents into a shash function.
(6) Add functions to walk through an ITER_XARRAY iterator and perform
various sorts of cleanup on the folios held therein, to be used on I/O
completion.
(7) Add a function to read from the transport TCP socket directly into an
iterator.
Then come the patches that actually do the work of iteratorising cifs:
(8) The main patch. Replace page lists with iterators. It extracts the
pages from ITER_UBUF and ITER_IOVEC iterators to an ITER_BVEC
iterator, pinning or getting refs on them, before passing them down as
the I/O may be done from a worker thread.
The iterator is extracted into a scatterlist in order to talk to the
crypto interface or to do RDMA.
(9) In the cifs RDMA code, extract the iterator into an RDMA SGE[] list,
removing the scatterlist intermediate - at least for smbd_send().
There appear to be other ways for cifs to talk to the RDMA layer that
don't go through that that I haven't managed to work out.
(10) Remove a chunk of now-unused code.
(11) Allow DIO to/from KVEC-type iterators.
I've pushed the patches here also:
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=iov-cifs
David
Link: https://lore.kernel.org/r/166697254399.61150.1256557652599252121.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/20230131182855.4027499-1-dhowells@redhat.com/ # v1
David Howells (11):
netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator
netfs: Add a function to extract an iterator into a scatterlist
cifs: Add a function to build an RDMA SGE list from an iterator
cifs: Add a function to Hash the contents of an iterator
cifs: Add some helper functions
cifs: Add a function to read into an iter from a socket
cifs: Change the I/O paths to use an iterator rather than a page list
cifs: Build the RDMA SGE list directly from an iterator
cifs: Remove unused code
cifs: DIO to/from KVEC-type iterators should now work
cifs: Fix problem with encrypted RDMA data read
fs/cifs/Kconfig | 1 +
fs/cifs/cifsencrypt.c | 172 +++-
fs/cifs/cifsfs.h | 3 +
fs/cifs/cifsglob.h | 66 +-
fs/cifs/cifsproto.h | 11 +-
fs/cifs/cifssmb.c | 15 +-
fs/cifs/connect.c | 14 +
fs/cifs/file.c | 1750 ++++++++++++++++++-----------------------
fs/cifs/fscache.c | 22 +-
fs/cifs/fscache.h | 10 +-
fs/cifs/misc.c | 128 +--
fs/cifs/smb2ops.c | 365 ++++-----
fs/cifs/smb2pdu.c | 53 +-
fs/cifs/smbdirect.c | 535 ++++++++-----
fs/cifs/smbdirect.h | 7 +-
fs/cifs/transport.c | 54 +-
fs/netfs/Makefile | 1 +
fs/netfs/iterator.c | 372 +++++++++
include/linux/netfs.h | 8 +
mm/vmalloc.c | 1 +
20 files changed, 1914 insertions(+), 1674 deletions(-)
create mode 100644 fs/netfs/iterator.c
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
@ 2023-02-10 23:31 ` David Howells
2023-02-10 23:31 ` [PATCH 02/11] netfs: Add a function to extract an iterator into a scatterlist David Howells
` (9 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:31 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French, linux-cachefs
Add a function to extract the pages from a user-space supplied iterator
(UBUF- or IOVEC-type) into a BVEC-type iterator, retaining the pages by
getting a pin on them (as FOLL_PIN) as we go.
This is useful in three situations:
(1) A userspace thread may have a sibling that unmaps or remaps the
process's VM during the operation, changing the assignment of the
pages and potentially causing an error. Retaining the pages keeps
some pages around, even if this occurs; futher, we find out at the
point of extraction if EFAULT is going to be incurred.
(2) Pages might get swapped out/discarded if not retained, so we want to
retain them to avoid the reload causing a deadlock due to a DIO
from/to an mmapped region on the same file.
(3) The iterator may get passed to sendmsg() by the filesystem. If a
fault occurs, we may get a short write to a TCP stream that's then
tricky to recover from.
We don't deal with other types of iterator here, leaving it to other
mechanisms to retain the pages (eg. PG_locked, PG_writeback and the pipe
lock).
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: linux-cachefs@redhat.com
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
fs/netfs/Makefile | 1 +
fs/netfs/iterator.c | 103 ++++++++++++++++++++++++++++++++++++++++++
include/linux/netfs.h | 4 ++
3 files changed, 108 insertions(+)
create mode 100644 fs/netfs/iterator.c
diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile
index f684c0cd1ec5..386d6fb92793 100644
--- a/fs/netfs/Makefile
+++ b/fs/netfs/Makefile
@@ -3,6 +3,7 @@
netfs-y := \
buffered_read.o \
io.o \
+ iterator.o \
main.o \
objects.o
diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
new file mode 100644
index 000000000000..6f0d79080abc
--- /dev/null
+++ b/fs/netfs/iterator.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Iterator helpers.
+ *
+ * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/netfs.h>
+#include "internal.h"
+
+/**
+ * netfs_extract_user_iter - Extract the pages from a user iterator into a bvec
+ * @orig: The original iterator
+ * @orig_len: The amount of iterator to copy
+ * @new: The iterator to be set up
+ * @extraction_flags: Flags to qualify the request
+ *
+ * Extract the page fragments from the given amount of the source iterator and
+ * build up a second iterator that refers to all of those bits. This allows
+ * the original iterator to disposed of.
+ *
+ * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA be
+ * allowed on the pages extracted.
+ *
+ * On success, the number of elements in the bvec is returned, the original
+ * iterator will have been advanced by the amount extracted.
+ *
+ * The iov_iter_extract_mode() function should be used to query how cleanup
+ * should be performed.
+ */
+ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
+ struct iov_iter *new,
+ iov_iter_extraction_t extraction_flags)
+{
+ struct bio_vec *bv = NULL;
+ struct page **pages;
+ unsigned int cur_npages;
+ unsigned int max_pages;
+ unsigned int npages = 0;
+ unsigned int i;
+ ssize_t ret;
+ size_t count = orig_len, offset, len;
+ size_t bv_size, pg_size;
+
+ if (WARN_ON_ONCE(!iter_is_ubuf(orig) && !iter_is_iovec(orig)))
+ return -EIO;
+
+ max_pages = iov_iter_npages(orig, INT_MAX);
+ bv_size = array_size(max_pages, sizeof(*bv));
+ bv = kvmalloc(bv_size, GFP_KERNEL);
+ if (!bv)
+ return -ENOMEM;
+
+ /* Put the page list at the end of the bvec list storage. bvec
+ * elements are larger than page pointers, so as long as we work
+ * 0->last, we should be fine.
+ */
+ pg_size = array_size(max_pages, sizeof(*pages));
+ pages = (void *)bv + bv_size - pg_size;
+
+ while (count && npages < max_pages) {
+ ret = iov_iter_extract_pages(orig, &pages, count,
+ max_pages - npages, extraction_flags,
+ &offset);
+ if (ret < 0) {
+ pr_err("Couldn't get user pages (rc=%zd)\n", ret);
+ break;
+ }
+
+ if (ret > count) {
+ pr_err("get_pages rc=%zd more than %zu\n", ret, count);
+ break;
+ }
+
+ count -= ret;
+ ret += offset;
+ cur_npages = DIV_ROUND_UP(ret, PAGE_SIZE);
+
+ if (npages + cur_npages > max_pages) {
+ pr_err("Out of bvec array capacity (%u vs %u)\n",
+ npages + cur_npages, max_pages);
+ break;
+ }
+
+ for (i = 0; i < cur_npages; i++) {
+ len = ret > PAGE_SIZE ? PAGE_SIZE : ret;
+ bv[npages + i].bv_page = *pages++;
+ bv[npages + i].bv_offset = offset;
+ bv[npages + i].bv_len = len - offset;
+ ret -= len;
+ offset = 0;
+ }
+
+ npages += cur_npages;
+ }
+
+ iov_iter_bvec(new, orig->data_source, bv, npages, orig_len - count);
+ return npages;
+}
+EXPORT_SYMBOL_GPL(netfs_extract_user_iter);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 4c76ddfb6a67..b11a84f6c32b 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -17,6 +17,7 @@
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
+#include <linux/uio.h>
enum netfs_sreq_ref_trace;
@@ -296,6 +297,9 @@ void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
bool was_async, enum netfs_sreq_ref_trace what);
void netfs_stats_show(struct seq_file *);
+ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
+ struct iov_iter *new,
+ iov_iter_extraction_t extraction_flags);
/**
* netfs_inode - Get the netfs inode context from the inode
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 02/11] netfs: Add a function to extract an iterator into a scatterlist
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
2023-02-10 23:31 ` [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
@ 2023-02-10 23:31 ` David Howells
2023-02-10 23:31 ` [PATCH 03/11] cifs: Add a function to build an RDMA SGE list from an iterator David Howells
` (8 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:31 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French, linux-cachefs
Provide a function for filling in a scatterlist from the list of pages
contained in an iterator.
If the iterator is UBUF- or IOBUF-type, the pages have a pin taken on them
(as FOLL_PIN).
If the iterator is BVEC-, KVEC- or XARRAY-type, no pin is taken on the
pages and it is left to the caller to manage their lifetime. It cannot be
assumed that a ref can be validly taken, particularly in the case of a KVEC
iterator.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: linux-cachefs@redhat.com
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
fs/netfs/iterator.c | 269 ++++++++++++++++++++++++++++++++++++++++++
include/linux/netfs.h | 4 +
mm/vmalloc.c | 1 +
3 files changed, 274 insertions(+)
diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 6f0d79080abc..49e674846b78 100644
--- a/fs/netfs/iterator.c
+++ b/fs/netfs/iterator.c
@@ -7,7 +7,9 @@
#include <linux/export.h>
#include <linux/slab.h>
+#include <linux/mm.h>
#include <linux/uio.h>
+#include <linux/scatterlist.h>
#include <linux/netfs.h>
#include "internal.h"
@@ -101,3 +103,270 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
return npages;
}
EXPORT_SYMBOL_GPL(netfs_extract_user_iter);
+
+/*
+ * Extract and pin a list of up to sg_max pages from UBUF- or IOVEC-class
+ * iterators, and add them to the scatterlist.
+ */
+static ssize_t netfs_extract_user_to_sg(struct iov_iter *iter,
+ ssize_t maxsize,
+ struct sg_table *sgtable,
+ unsigned int sg_max,
+ iov_iter_extraction_t extraction_flags)
+{
+ struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+ struct page **pages;
+ unsigned int npages;
+ ssize_t ret = 0, res;
+ size_t len, off;
+
+ /* We decant the page list into the tail of the scatterlist */
+ pages = (void *)sgtable->sgl + array_size(sg_max, sizeof(struct scatterlist));
+ pages -= sg_max;
+
+ do {
+ res = iov_iter_extract_pages(iter, &pages, maxsize, sg_max,
+ extraction_flags, &off);
+ if (res < 0)
+ goto failed;
+
+ len = res;
+ maxsize -= len;
+ ret += len;
+ npages = DIV_ROUND_UP(off + len, PAGE_SIZE);
+ sg_max -= npages;
+
+ for (; npages < 0; npages--) {
+ struct page *page = *pages;
+ size_t seg = min_t(size_t, PAGE_SIZE - off, len);
+
+ *pages++ = NULL;
+ sg_set_page(sg, page, len, off);
+ sgtable->nents++;
+ sg++;
+ len -= seg;
+ off = 0;
+ }
+ } while (maxsize > 0 && sg_max > 0);
+
+ return ret;
+
+failed:
+ while (sgtable->nents > sgtable->orig_nents)
+ put_page(sg_page(&sgtable->sgl[--sgtable->nents]));
+ return res;
+}
+
+/*
+ * Extract up to sg_max pages from a BVEC-type iterator and add them to the
+ * scatterlist. The pages are not pinned.
+ */
+static ssize_t netfs_extract_bvec_to_sg(struct iov_iter *iter,
+ ssize_t maxsize,
+ struct sg_table *sgtable,
+ unsigned int sg_max,
+ iov_iter_extraction_t extraction_flags)
+{
+ const struct bio_vec *bv = iter->bvec;
+ struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+ 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;
+
+ sg_set_page(sg, bv[i].bv_page, len, off);
+ sgtable->nents++;
+ sg++;
+ sg_max--;
+
+ ret += len;
+ maxsize -= len;
+ if (maxsize <= 0 || sg_max == 0)
+ break;
+ start = 0;
+ }
+
+ if (ret > 0)
+ iov_iter_advance(iter, ret);
+ return ret;
+}
+
+/*
+ * Extract up to sg_max pages from a KVEC-type iterator and add them to the
+ * scatterlist. This can deal with vmalloc'd buffers as well as kmalloc'd or
+ * static buffers. The pages are not pinned.
+ */
+static ssize_t netfs_extract_kvec_to_sg(struct iov_iter *iter,
+ ssize_t maxsize,
+ struct sg_table *sgtable,
+ unsigned int sg_max,
+ iov_iter_extraction_t extraction_flags)
+{
+ const struct kvec *kv = iter->kvec;
+ struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+ 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;
+ ret += 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(kaddr);
+
+ sg_set_page(sg, page, len, off);
+ sgtable->nents++;
+ sg++;
+ sg_max--;
+
+ len -= seg;
+ kaddr += PAGE_SIZE;
+ off = 0;
+ } while (len > 0 && sg_max > 0);
+
+ if (maxsize <= 0 || sg_max == 0)
+ break;
+ start = 0;
+ }
+
+ if (ret > 0)
+ iov_iter_advance(iter, ret);
+ return ret;
+}
+
+/*
+ * Extract up to sg_max folios from an XARRAY-type iterator and add them to
+ * the scatterlist. The pages are not pinned.
+ */
+static ssize_t netfs_extract_xarray_to_sg(struct iov_iter *iter,
+ ssize_t maxsize,
+ struct sg_table *sgtable,
+ unsigned int sg_max,
+ iov_iter_extraction_t extraction_flags)
+{
+ struct scatterlist *sg = sgtable->sgl + sgtable->nents;
+ 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 offset, 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;
+
+ offset = offset_in_folio(folio, start);
+ len = min_t(size_t, maxsize, folio_size(folio) - offset);
+
+ sg_set_page(sg, folio_page(folio, 0), len, offset);
+ sgtable->nents++;
+ sg++;
+ sg_max--;
+
+ maxsize -= len;
+ ret += len;
+ if (maxsize <= 0 || sg_max == 0)
+ break;
+ }
+
+ rcu_read_unlock();
+ if (ret > 0)
+ iov_iter_advance(iter, ret);
+ return ret;
+}
+
+/**
+ * netfs_extract_iter_to_sg - Extract pages from an iterator and add ot an sglist
+ * @iter: The iterator to extract from
+ * @maxsize: The amount of iterator to copy
+ * @sgtable: The scatterlist table to fill in
+ * @sg_max: Maximum number of elements in @sgtable that may be filled
+ * @extraction_flags: Flags to qualify the request
+ *
+ * Extract the page fragments from the given amount of the source iterator and
+ * add them to a scatterlist that refers to all of those bits, to a maximum
+ * addition of @sg_max elements.
+ *
+ * The pages referred to by UBUF- and IOVEC-type iterators are extracted and
+ * pinned; BVEC-, KVEC- and XARRAY-type are extracted but aren't pinned; PIPE-
+ * and DISCARD-type are not supported.
+ *
+ * No end mark is placed on the scatterlist; that's left to the caller.
+ *
+ * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA
+ * be allowed on the pages extracted.
+ *
+ * If successul, @sgtable->nents is updated to include the number of elements
+ * added and the number of bytes added is returned. @sgtable->orig_nents is
+ * left unaltered.
+ *
+ * The iov_iter_extract_mode() function should be used to query how cleanup
+ * should be performed.
+ */
+ssize_t netfs_extract_iter_to_sg(struct iov_iter *iter, size_t maxsize,
+ struct sg_table *sgtable, unsigned int sg_max,
+ iov_iter_extraction_t extraction_flags)
+{
+ if (maxsize == 0)
+ return 0;
+
+ switch (iov_iter_type(iter)) {
+ case ITER_UBUF:
+ case ITER_IOVEC:
+ return netfs_extract_user_to_sg(iter, maxsize, sgtable, sg_max,
+ extraction_flags);
+ case ITER_BVEC:
+ return netfs_extract_bvec_to_sg(iter, maxsize, sgtable, sg_max,
+ extraction_flags);
+ case ITER_KVEC:
+ return netfs_extract_kvec_to_sg(iter, maxsize, sgtable, sg_max,
+ extraction_flags);
+ case ITER_XARRAY:
+ return netfs_extract_xarray_to_sg(iter, maxsize, sgtable, sg_max,
+ extraction_flags);
+ default:
+ pr_err("netfs_extract_iter_to_sg(%u) unsupported\n",
+ iov_iter_type(iter));
+ WARN_ON_ONCE(1);
+ return -EIO;
+ }
+}
+EXPORT_SYMBOL_GPL(netfs_extract_iter_to_sg);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index b11a84f6c32b..a1f3522daa69 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -300,6 +300,10 @@ void netfs_stats_show(struct seq_file *);
ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
struct iov_iter *new,
iov_iter_extraction_t extraction_flags);
+struct sg_table;
+ssize_t netfs_extract_iter_to_sg(struct iov_iter *iter, size_t len,
+ struct sg_table *sgtable, unsigned int sg_max,
+ iov_iter_extraction_t extraction_flags);
/**
* netfs_inode - Get the netfs inode context from the inode
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ca71de7c9d77..61f5bec0f2b6 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -656,6 +656,7 @@ int is_vmalloc_or_module_addr(const void *x)
#endif
return is_vmalloc_addr(x);
}
+EXPORT_SYMBOL_GPL(is_vmalloc_or_module_addr);
/*
* Walk a vmap address to the struct page it maps. Huge vmap mappings will
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 03/11] cifs: Add a function to build an RDMA SGE list from an iterator
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
2023-02-10 23:31 ` [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
2023-02-10 23:31 ` [PATCH 02/11] netfs: Add a function to extract an iterator into a scatterlist David Howells
@ 2023-02-10 23:31 ` David Howells
2023-02-10 23:31 ` [PATCH 04/11] cifs: Add a function to Hash the contents of " David Howells
` (7 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:31 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French, linux-rdma
Add a function to add elements onto an RDMA SGE list representing page
fragments extracted from a BVEC-, KVEC- or XARRAY-type iterator and DMA
mapped until the maximum number of elements is reached.
Nothing is done to make sure the pages remain present - that must be done
by the caller.
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
cc: linux-fsdevel@vger.kernel.org
cc: linux-rdma@vger.kernel.org
Link: https://lore.kernel.org/r/166697256704.61150.17388516338310645808.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732028840.3186319.8512284239779728860.stgit@warthog.procyon.org.uk/ # rfc
---
fs/cifs/smbdirect.c | 214 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 214 insertions(+)
diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 8c816b25ce7c..3e0aacddc291 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -44,6 +44,17 @@ static int smbd_post_send_page(struct smbd_connection *info,
static void destroy_mr_list(struct smbd_connection *info);
static int allocate_mr_list(struct smbd_connection *info);
+struct smb_extract_to_rdma {
+ struct ib_sge *sge;
+ unsigned int nr_sge;
+ unsigned int max_sge;
+ struct ib_device *device;
+ u32 local_dma_lkey;
+ enum dma_data_direction direction;
+};
+static ssize_t smb_extract_iter_to_rdma(struct iov_iter *iter, size_t len,
+ struct smb_extract_to_rdma *rdma);
+
/* SMBD version number */
#define SMBD_V1 0x0100
@@ -2490,3 +2501,206 @@ int smbd_deregister_mr(struct smbd_mr *smbdirect_mr)
return rc;
}
+
+static bool smb_set_sge(struct smb_extract_to_rdma *rdma,
+ struct page *lowest_page, size_t off, size_t len)
+{
+ struct ib_sge *sge = &rdma->sge[rdma->nr_sge];
+ u64 addr;
+
+ addr = ib_dma_map_page(rdma->device, lowest_page,
+ off, len, rdma->direction);
+ if (ib_dma_mapping_error(rdma->device, addr))
+ return false;
+
+ sge->addr = addr;
+ sge->length = len;
+ sge->lkey = rdma->local_dma_lkey;
+ rdma->nr_sge++;
+ 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;
+ }
+
+ 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(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;
+ }
+
+ 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_lock();
+ return -EIO;
+ }
+
+ maxsize -= len;
+ ret += len;
+ if (rdma->nr_sge >= rdma->max_sge || maxsize <= 0)
+ break;
+ }
+
+ rcu_read_unlock();
+ 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
+ * is appended to, up to the maximum number of elements set in the parameter
+ * block.
+ *
+ * The extracted page fragments are not pinned or ref'd in any way; if an
+ * IOVEC/UBUF-type iterator is to be used, it should be converted to a
+ * BVEC-type iterator and the pages pinned, ref'd or otherwise held in some
+ * way.
+ */
+static ssize_t smb_extract_iter_to_rdma(struct iov_iter *iter, size_t len,
+ struct smb_extract_to_rdma *rdma)
+{
+ ssize_t ret;
+ 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_XARRAY:
+ ret = smb_extract_xarray_to_rdma(iter, rdma, len);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return -EIO;
+ }
+
+ if (ret > 0) {
+ iov_iter_advance(iter, ret);
+ } else if (ret < 0) {
+ while (rdma->nr_sge > before) {
+ struct ib_sge *sge = &rdma->sge[rdma->nr_sge--];
+
+ ib_dma_unmap_single(rdma->device, sge->addr, sge->length,
+ rdma->direction);
+ sge->addr = 0;
+ }
+ }
+
+ return ret;
+}
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 04/11] cifs: Add a function to Hash the contents of an iterator
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (2 preceding siblings ...)
2023-02-10 23:31 ` [PATCH 03/11] cifs: Add a function to build an RDMA SGE list from an iterator David Howells
@ 2023-02-10 23:31 ` David Howells
2023-02-10 23:31 ` [PATCH 05/11] cifs: Add some helper functions David Howells
` (6 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:31 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French, linux-crypto
Add a function to push the contents of a BVEC-, KVEC- or XARRAY-type
iterator into a symmetric hash algorithm.
UBUF- and IOBUF-type iterators are not supported on the assumption that
either we're doing buffered I/O, in which case we won't see them, or we're
doing direct I/O, in which case the iterator will have been extracted into
a BVEC-type iterator higher up.
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: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-crypto@vger.kernel.org
Link: https://lore.kernel.org/r/166697257423.61150.12070648579830206483.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732029577.3186319.17162612653237909961.stgit@warthog.procyon.org.uk/ # rfc
---
fs/cifs/cifsencrypt.c | 144 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 144 insertions(+)
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index cbc18b4a9cb2..7be589aeb520 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -24,6 +24,150 @@
#include "../smbfs_common/arc4.h"
#include <crypto/aead.h>
+/*
+ * Hash data from a BVEC-type iterator.
+ */
+static int cifs_shash_bvec(const struct iov_iter *iter, ssize_t maxsize,
+ struct shash_desc *shash)
+{
+ const struct bio_vec *bv = iter->bvec;
+ unsigned long start = iter->iov_offset;
+ unsigned int i;
+ void *p;
+ int ret;
+
+ 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;
+
+ p = kmap_local_page(bv[i].bv_page);
+ ret = crypto_shash_update(shash, p + off, len);
+ kunmap_local(p);
+ if (ret < 0)
+ return ret;
+
+ maxsize -= len;
+ if (maxsize <= 0)
+ break;
+ start = 0;
+ }
+
+ return 0;
+}
+
+/*
+ * Hash data from a KVEC-type iterator.
+ */
+static int cifs_shash_kvec(const struct iov_iter *iter, ssize_t maxsize,
+ struct shash_desc *shash)
+{
+ const struct kvec *kv = iter->kvec;
+ unsigned long start = iter->iov_offset;
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < iter->nr_segs; i++) {
+ size_t len;
+
+ len = kv[i].iov_len;
+ if (start >= len) {
+ start -= len;
+ continue;
+ }
+
+ len = min_t(size_t, maxsize, len - start);
+ ret = crypto_shash_update(shash, kv[i].iov_base + start, len);
+ if (ret < 0)
+ return ret;
+ maxsize -= len;
+
+ if (maxsize <= 0)
+ break;
+ start = 0;
+ }
+
+ return 0;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Pass the data from an iterator into a hash.
+ */
+static int cifs_shash_iter(const struct iov_iter *iter, size_t maxsize,
+ struct shash_desc *shash)
+{
+ if (maxsize == 0)
+ return 0;
+
+ switch (iov_iter_type(iter)) {
+ case ITER_BVEC:
+ return cifs_shash_bvec(iter, maxsize, shash);
+ case ITER_KVEC:
+ return cifs_shash_kvec(iter, maxsize, shash);
+ case ITER_XARRAY:
+ return cifs_shash_xarray(iter, maxsize, shash);
+ default:
+ pr_err("cifs_shash_iter(%u) unsupported\n", iov_iter_type(iter));
+ WARN_ON_ONCE(1);
+ return -EIO;
+ }
+}
+
int __cifs_calc_signature(struct smb_rqst *rqst,
struct TCP_Server_Info *server, char *signature,
struct shash_desc *shash)
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 05/11] cifs: Add some helper functions
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (3 preceding siblings ...)
2023-02-10 23:31 ` [PATCH 04/11] cifs: Add a function to Hash the contents of " David Howells
@ 2023-02-10 23:31 ` David Howells
2023-02-10 23:32 ` [PATCH 06/11] cifs: Add a function to read into an iter from a socket David Howells
` (5 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:31 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French
Add some helper functions to manipulate the folio marks by iterating
through a list of folios held in an xarray rather than using a page list.
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: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
Link: https://lore.kernel.org/r/164928616583.457102.15157033997163988344.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165211418840.3154751.3090684430628501879.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165348878940.2106726.204291614267188735.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165364825674.3334034.3356201708659748648.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/166126394799.708021.10637797063862600488.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/166697258147.61150.9940790486999562110.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732030314.3186319.9209944805565413627.stgit@warthog.procyon.org.uk/ # rfc
---
fs/cifs/cifsfs.h | 3 ++
fs/cifs/file.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 96 insertions(+)
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 63a0ac2b9355..492d6f47a751 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -110,6 +110,9 @@ extern int cifs_file_strict_mmap(struct file *file, struct vm_area_struct *vma);
extern const struct file_operations cifs_dir_ops;
extern int cifs_dir_open(struct inode *inode, struct file *file);
extern int cifs_readdir(struct file *file, struct dir_context *ctx);
+extern void cifs_pages_written_back(struct inode *inode, loff_t start, unsigned int len);
+extern void cifs_pages_write_failed(struct inode *inode, loff_t start, unsigned int len);
+extern void cifs_pages_write_redirty(struct inode *inode, loff_t start, unsigned int len);
/* Functions related to dir entries */
extern const struct dentry_operations cifs_dentry_ops;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 1c3b4ed1de94..5421aa5e35cc 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -36,6 +36,99 @@
#include "cifs_ioctl.h"
#include "cached_dir.h"
+/*
+ * Completion of write to server.
+ */
+void cifs_pages_written_back(struct inode *inode, loff_t start, unsigned int len)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct folio *folio;
+ pgoff_t end;
+
+ XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
+
+ if (!len)
+ return;
+
+ rcu_read_lock();
+
+ end = (start + len - 1) / PAGE_SIZE;
+ xas_for_each(&xas, folio, end) {
+ if (!folio_test_writeback(folio)) {
+ WARN_ONCE(1, "bad %x @%llx page %lx %lx\n",
+ len, start, folio_index(folio), end);
+ continue;
+ }
+
+ folio_detach_private(folio);
+ folio_end_writeback(folio);
+ }
+
+ rcu_read_unlock();
+}
+
+/*
+ * Failure of write to server.
+ */
+void cifs_pages_write_failed(struct inode *inode, loff_t start, unsigned int len)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct folio *folio;
+ pgoff_t end;
+
+ XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
+
+ if (!len)
+ return;
+
+ rcu_read_lock();
+
+ end = (start + len - 1) / PAGE_SIZE;
+ xas_for_each(&xas, folio, end) {
+ if (!folio_test_writeback(folio)) {
+ WARN_ONCE(1, "bad %x @%llx page %lx %lx\n",
+ len, start, folio_index(folio), end);
+ continue;
+ }
+
+ folio_set_error(folio);
+ folio_end_writeback(folio);
+ }
+
+ rcu_read_unlock();
+}
+
+/*
+ * Redirty pages after a temporary failure.
+ */
+void cifs_pages_write_redirty(struct inode *inode, loff_t start, unsigned int len)
+{
+ struct address_space *mapping = inode->i_mapping;
+ struct folio *folio;
+ pgoff_t end;
+
+ XA_STATE(xas, &mapping->i_pages, start / PAGE_SIZE);
+
+ if (!len)
+ return;
+
+ rcu_read_lock();
+
+ end = (start + len - 1) / PAGE_SIZE;
+ xas_for_each(&xas, folio, end) {
+ if (!folio_test_writeback(folio)) {
+ WARN_ONCE(1, "bad %x @%llx page %lx %lx\n",
+ len, start, folio_index(folio), end);
+ continue;
+ }
+
+ filemap_dirty_folio(folio->mapping, folio);
+ folio_end_writeback(folio);
+ }
+
+ rcu_read_unlock();
+}
+
/*
* Mark as invalid, all open files on tree connections since they
* were closed when session to server was lost.
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 06/11] cifs: Add a function to read into an iter from a socket
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (4 preceding siblings ...)
2023-02-10 23:31 ` [PATCH 05/11] cifs: Add some helper functions David Howells
@ 2023-02-10 23:32 ` David Howells
2023-02-10 23:32 ` [PATCH 08/11] cifs: Build the RDMA SGE list directly from an iterator David Howells
` (4 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:32 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French
Add a helper function to read data from a socket into the given iterator.
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: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
Link: https://lore.kernel.org/r/164928617874.457102.10021662143234315566.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165211419563.3154751.18431990381145195050.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165348879662.2106726.16881134187242702351.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165364826398.3334034.12541600783145647319.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/166126395495.708021.12328677373159554478.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/166697258876.61150.3530237818849429372.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732031039.3186319.10691316510079412635.stgit@warthog.procyon.org.uk/ # rfc
---
fs/cifs/cifsproto.h | 3 +++
fs/cifs/connect.c | 14 ++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 1207b39686fb..cb7a3fe89278 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -244,6 +244,9 @@ extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
struct page *page,
unsigned int page_offset,
unsigned int to_read);
+int cifs_read_iter_from_socket(struct TCP_Server_Info *server,
+ struct iov_iter *iter,
+ unsigned int to_read);
extern int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb);
void cifs_mount_put_conns(struct cifs_mount_ctx *mnt_ctx);
int cifs_mount_get_session(struct cifs_mount_ctx *mnt_ctx);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index b2a04b4e89a5..152b457b849f 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -765,6 +765,20 @@ cifs_read_page_from_socket(struct TCP_Server_Info *server, struct page *page,
return cifs_readv_from_socket(server, &smb_msg);
}
+int
+cifs_read_iter_from_socket(struct TCP_Server_Info *server, struct iov_iter *iter,
+ unsigned int to_read)
+{
+ struct msghdr smb_msg = { .msg_iter = *iter };
+ int ret;
+
+ iov_iter_truncate(&smb_msg.msg_iter, to_read);
+ ret = cifs_readv_from_socket(server, &smb_msg);
+ if (ret > 0)
+ iov_iter_advance(iter, ret);
+ return ret;
+}
+
static bool
is_smb_response(struct TCP_Server_Info *server, unsigned char type)
{
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 08/11] cifs: Build the RDMA SGE list directly from an iterator
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (5 preceding siblings ...)
2023-02-10 23:32 ` [PATCH 06/11] cifs: Add a function to read into an iter from a socket David Howells
@ 2023-02-10 23:32 ` David Howells
2023-02-10 23:32 ` [PATCH 09/11] cifs: Remove unused code David Howells
` (3 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:32 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French, linux-rdma
In the depths of the cifs RDMA code, extract part of an iov iterator
directly into an SGE list without going through an intermediate
scatterlist.
Note that this doesn't support extraction from an IOBUF- or UBUF-type
iterator (ie. user-supplied buffer). The assumption is that the higher
layers will extract those to a BVEC-type iterator first and do whatever is
required to stop the pages from going away.
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
cc: linux-rdma@vger.kernel.org
Link: https://lore.kernel.org/r/166697260361.61150.5064013393408112197.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732032518.3186319.1859601819981624629.stgit@warthog.procyon.org.uk/ # rfc
---
fs/cifs/smbdirect.c | 153 ++++++++++++++++++--------------------------
fs/cifs/smbdirect.h | 3 +-
2 files changed, 63 insertions(+), 93 deletions(-)
diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 0eb32bbfc467..31c4dc8212c3 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -828,16 +828,16 @@ static int smbd_post_send(struct smbd_connection *info,
return rc;
}
-static int smbd_post_send_sgl(struct smbd_connection *info,
- struct scatterlist *sgl, int data_length, int remaining_data_length)
+static int smbd_post_send_iter(struct smbd_connection *info,
+ struct iov_iter *iter,
+ int *_remaining_data_length)
{
- int num_sgs;
int i, rc;
int header_length;
+ int data_length;
struct smbd_request *request;
struct smbd_data_transfer *packet;
int new_credits;
- struct scatterlist *sg;
wait_credit:
/* Wait for send credits. A SMBD packet needs one credit */
@@ -881,6 +881,30 @@ static int smbd_post_send_sgl(struct smbd_connection *info,
}
request->info = info;
+ memset(request->sge, 0, sizeof(request->sge));
+
+ /* Fill in the data payload to find out how much data we can add */
+ if (iter) {
+ struct smb_extract_to_rdma extract = {
+ .nr_sge = 1,
+ .max_sge = SMBDIRECT_MAX_SEND_SGE,
+ .sge = request->sge,
+ .device = info->id->device,
+ .local_dma_lkey = info->pd->local_dma_lkey,
+ .direction = DMA_TO_DEVICE,
+ };
+
+ rc = smb_extract_iter_to_rdma(iter, *_remaining_data_length,
+ &extract);
+ if (rc < 0)
+ goto err_dma;
+ data_length = rc;
+ request->num_sge = extract.nr_sge;
+ *_remaining_data_length -= data_length;
+ } else {
+ data_length = 0;
+ request->num_sge = 1;
+ }
/* Fill in the packet header */
packet = smbd_request_payload(request);
@@ -902,7 +926,7 @@ static int smbd_post_send_sgl(struct smbd_connection *info,
else
packet->data_offset = cpu_to_le32(24);
packet->data_length = cpu_to_le32(data_length);
- packet->remaining_data_length = cpu_to_le32(remaining_data_length);
+ packet->remaining_data_length = cpu_to_le32(*_remaining_data_length);
packet->padding = 0;
log_outgoing(INFO, "credits_requested=%d credits_granted=%d data_offset=%d data_length=%d remaining_data_length=%d\n",
@@ -918,7 +942,6 @@ static int smbd_post_send_sgl(struct smbd_connection *info,
if (!data_length)
header_length = offsetof(struct smbd_data_transfer, padding);
- request->num_sge = 1;
request->sge[0].addr = ib_dma_map_single(info->id->device,
(void *)packet,
header_length,
@@ -932,23 +955,6 @@ static int smbd_post_send_sgl(struct smbd_connection *info,
request->sge[0].length = header_length;
request->sge[0].lkey = info->pd->local_dma_lkey;
- /* Fill in the packet data payload */
- num_sgs = sgl ? sg_nents(sgl) : 0;
- for_each_sg(sgl, sg, num_sgs, i) {
- request->sge[i+1].addr =
- ib_dma_map_page(info->id->device, sg_page(sg),
- sg->offset, sg->length, DMA_TO_DEVICE);
- if (ib_dma_mapping_error(
- info->id->device, request->sge[i+1].addr)) {
- rc = -EIO;
- request->sge[i+1].addr = 0;
- goto err_dma;
- }
- request->sge[i+1].length = sg->length;
- request->sge[i+1].lkey = info->pd->local_dma_lkey;
- request->num_sge++;
- }
-
rc = smbd_post_send(info, request);
if (!rc)
return 0;
@@ -987,8 +993,10 @@ static int smbd_post_send_sgl(struct smbd_connection *info,
*/
static int smbd_post_send_empty(struct smbd_connection *info)
{
+ int remaining_data_length = 0;
+
info->count_send_empty++;
- return smbd_post_send_sgl(info, NULL, 0, 0);
+ return smbd_post_send_iter(info, NULL, &remaining_data_length);
}
/*
@@ -1933,42 +1941,6 @@ int smbd_recv(struct smbd_connection *info, struct msghdr *msg)
return rc;
}
-/*
- * Send the contents of an iterator
- * @iter: The iterator to send
- * @_remaining_data_length: remaining data to send in this payload
- */
-static int smbd_post_send_iter(struct smbd_connection *info,
- struct iov_iter *iter,
- int *_remaining_data_length)
-{
- struct scatterlist sgl[SMBDIRECT_MAX_SEND_SGE - 1];
- unsigned int max_payload = info->max_send_size - sizeof(struct smbd_data_transfer);
- ssize_t rc;
-
- /* We're not expecting a user-backed iter */
- WARN_ON(iov_iter_extract_will_pin(iter));
-
- do {
- struct sg_table sgtable = { .sgl = sgl };
- size_t maxlen = min_t(size_t, *_remaining_data_length, max_payload);
-
- sg_init_table(sgtable.sgl, ARRAY_SIZE(sgl));
- rc = netfs_extract_iter_to_sg(iter, maxlen,
- &sgtable, ARRAY_SIZE(sgl), 0);
- if (rc < 0)
- break;
- if (WARN_ON_ONCE(sgtable.nents == 0))
- return -EIO;
-
- sg_mark_end(&sgl[sgtable.nents - 1]);
- *_remaining_data_length -= rc;
- rc = smbd_post_send_sgl(info, sgl, rc, *_remaining_data_length);
- } while (rc == 0 && iov_iter_count(iter) > 0);
-
- return rc;
-}
-
/*
* Send data to transport
* Each rqst is transported as a SMBDirect payload
@@ -2129,10 +2101,10 @@ static void destroy_mr_list(struct smbd_connection *info)
cancel_work_sync(&info->mr_recovery_work);
list_for_each_entry_safe(mr, tmp, &info->mr_list, list) {
if (mr->state == MR_INVALIDATED)
- ib_dma_unmap_sg(info->id->device, mr->sgl,
- mr->sgl_count, mr->dir);
+ ib_dma_unmap_sg(info->id->device, mr->sgt.sgl,
+ mr->sgt.nents, mr->dir);
ib_dereg_mr(mr->mr);
- kfree(mr->sgl);
+ kfree(mr->sgt.sgl);
kfree(mr);
}
}
@@ -2167,11 +2139,10 @@ static int allocate_mr_list(struct smbd_connection *info)
info->mr_type, info->max_frmr_depth);
goto out;
}
- smbdirect_mr->sgl = kcalloc(
- info->max_frmr_depth,
- sizeof(struct scatterlist),
- GFP_KERNEL);
- if (!smbdirect_mr->sgl) {
+ smbdirect_mr->sgt.sgl = kcalloc(info->max_frmr_depth,
+ sizeof(struct scatterlist),
+ GFP_KERNEL);
+ if (!smbdirect_mr->sgt.sgl) {
log_rdma_mr(ERR, "failed to allocate sgl\n");
ib_dereg_mr(smbdirect_mr->mr);
goto out;
@@ -2190,7 +2161,7 @@ static int allocate_mr_list(struct smbd_connection *info)
list_for_each_entry_safe(smbdirect_mr, tmp, &info->mr_list, list) {
ib_dereg_mr(smbdirect_mr->mr);
- kfree(smbdirect_mr->sgl);
+ kfree(smbdirect_mr->sgt.sgl);
kfree(smbdirect_mr);
}
return -ENOMEM;
@@ -2244,22 +2215,20 @@ static struct smbd_mr *get_mr(struct smbd_connection *info)
/*
* Transcribe the pages from an iterator into an MR scatterlist.
- * @iter: The iterator to transcribe
- * @_remaining_data_length: remaining data to send in this payload
*/
static int smbd_iter_to_mr(struct smbd_connection *info,
struct iov_iter *iter,
- struct scatterlist *sgl,
- unsigned int num_pages)
+ struct sg_table *sgt,
+ unsigned int max_sg)
{
- struct sg_table sgtable = { .sgl = sgl };
int ret;
- sg_init_table(sgl, num_pages);
+ memset(sgt->sgl, 0, max_sg * sizeof(struct scatterlist));
- ret = netfs_extract_iter_to_sg(iter, iov_iter_count(iter),
- &sgtable, num_pages, 0);
+ ret = netfs_extract_iter_to_sg(iter, iov_iter_count(iter), sgt, max_sg, 0);
WARN_ON(ret < 0);
+ if (sgt->nents > 0)
+ sg_mark_end(&sgt->sgl[sgt->nents - 1]);
return ret;
}
@@ -2296,25 +2265,27 @@ struct smbd_mr *smbd_register_mr(struct smbd_connection *info,
dir = writing ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
smbdirect_mr->dir = dir;
smbdirect_mr->need_invalidate = need_invalidate;
- smbdirect_mr->sgl_count = num_pages;
+ smbdirect_mr->sgt.nents = 0;
+ smbdirect_mr->sgt.orig_nents = 0;
- log_rdma_mr(INFO, "num_pages=0x%x count=0x%zx\n",
- num_pages, iov_iter_count(iter));
- smbd_iter_to_mr(info, iter, smbdirect_mr->sgl, num_pages);
+ log_rdma_mr(INFO, "num_pages=0x%x count=0x%zx depth=%u\n",
+ num_pages, iov_iter_count(iter), info->max_frmr_depth);
+ smbd_iter_to_mr(info, iter, &smbdirect_mr->sgt, info->max_frmr_depth);
- rc = ib_dma_map_sg(info->id->device, smbdirect_mr->sgl, num_pages, dir);
+ rc = ib_dma_map_sg(info->id->device, smbdirect_mr->sgt.sgl,
+ smbdirect_mr->sgt.nents, dir);
if (!rc) {
log_rdma_mr(ERR, "ib_dma_map_sg num_pages=%x dir=%x rc=%x\n",
num_pages, dir, rc);
goto dma_map_error;
}
- rc = ib_map_mr_sg(smbdirect_mr->mr, smbdirect_mr->sgl, num_pages,
- NULL, PAGE_SIZE);
- if (rc != num_pages) {
+ rc = ib_map_mr_sg(smbdirect_mr->mr, smbdirect_mr->sgt.sgl,
+ smbdirect_mr->sgt.nents, NULL, PAGE_SIZE);
+ if (rc != smbdirect_mr->sgt.nents) {
log_rdma_mr(ERR,
- "ib_map_mr_sg failed rc = %d num_pages = %x\n",
- rc, num_pages);
+ "ib_map_mr_sg failed rc = %d nents = %x\n",
+ rc, smbdirect_mr->sgt.nents);
goto map_mr_error;
}
@@ -2346,8 +2317,8 @@ struct smbd_mr *smbd_register_mr(struct smbd_connection *info,
/* If all failed, attempt to recover this MR by setting it MR_ERROR*/
map_mr_error:
- ib_dma_unmap_sg(info->id->device, smbdirect_mr->sgl,
- smbdirect_mr->sgl_count, smbdirect_mr->dir);
+ ib_dma_unmap_sg(info->id->device, smbdirect_mr->sgt.sgl,
+ smbdirect_mr->sgt.nents, smbdirect_mr->dir);
dma_map_error:
smbdirect_mr->state = MR_ERROR;
@@ -2414,8 +2385,8 @@ int smbd_deregister_mr(struct smbd_mr *smbdirect_mr)
if (smbdirect_mr->state == MR_INVALIDATED) {
ib_dma_unmap_sg(
- info->id->device, smbdirect_mr->sgl,
- smbdirect_mr->sgl_count,
+ info->id->device, smbdirect_mr->sgt.sgl,
+ smbdirect_mr->sgt.nents,
smbdirect_mr->dir);
smbdirect_mr->state = MR_READY;
if (atomic_inc_return(&info->mr_ready_count) == 1)
diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h
index be2cf18b7fec..83f239f376f0 100644
--- a/fs/cifs/smbdirect.h
+++ b/fs/cifs/smbdirect.h
@@ -288,8 +288,7 @@ struct smbd_mr {
struct list_head list;
enum mr_state state;
struct ib_mr *mr;
- struct scatterlist *sgl;
- int sgl_count;
+ struct sg_table sgt;
enum dma_data_direction dir;
union {
struct ib_reg_wr wr;
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 09/11] cifs: Remove unused code
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (6 preceding siblings ...)
2023-02-10 23:32 ` [PATCH 08/11] cifs: Build the RDMA SGE list directly from an iterator David Howells
@ 2023-02-10 23:32 ` David Howells
2023-02-10 23:32 ` [PATCH 10/11] cifs: DIO to/from KVEC-type iterators should now work David Howells
` (2 subsequent siblings)
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:32 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French
Remove a bunch of functions that are no longer used and are commented out
after the conversion to use iterators throughout the I/O path.
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: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
Link: https://lore.kernel.org/r/164928621823.457102.8777804402615654773.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165211421039.3154751.15199634443157779005.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165348881165.2106726.2993852968344861224.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165364827876.3334034.9331465096417303889.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/166126396915.708021.2010212654244139442.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/166697261080.61150.17513116912567922274.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/166732033255.3186319.5527423437137895940.stgit@warthog.procyon.org.uk/ # rfc
---
fs/cifs/file.c | 606 -------------------------------------------------
1 file changed, 606 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 5de37e84a751..f3cedec9d22a 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2603,314 +2603,6 @@ static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
return rc;
}
-#if 0 // TODO: Remove for iov_iter support
-static struct cifs_writedata *
-wdata_alloc_and_fillpages(pgoff_t tofind, struct address_space *mapping,
- pgoff_t end, pgoff_t *index,
- unsigned int *found_pages)
-{
- struct cifs_writedata *wdata;
-
- wdata = cifs_writedata_alloc((unsigned int)tofind,
- cifs_writev_complete);
- if (!wdata)
- return NULL;
-
- *found_pages = find_get_pages_range_tag(mapping, index, end,
- PAGECACHE_TAG_DIRTY, tofind, wdata->pages);
- return wdata;
-}
-
-static unsigned int
-wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,
- struct address_space *mapping,
- struct writeback_control *wbc,
- pgoff_t end, pgoff_t *index, pgoff_t *next, bool *done)
-{
- unsigned int nr_pages = 0, i;
- struct page *page;
-
- for (i = 0; i < found_pages; i++) {
- page = wdata->pages[i];
- /*
- * At this point we hold neither the i_pages lock nor the
- * page lock: the page may be truncated or invalidated
- * (changing page->mapping to NULL), or even swizzled
- * back from swapper_space to tmpfs file mapping
- */
-
- if (nr_pages == 0)
- lock_page(page);
- else if (!trylock_page(page))
- break;
-
- if (unlikely(page->mapping != mapping)) {
- unlock_page(page);
- break;
- }
-
- if (!wbc->range_cyclic && page->index > end) {
- *done = true;
- unlock_page(page);
- break;
- }
-
- if (*next && (page->index != *next)) {
- /* Not next consecutive page */
- unlock_page(page);
- break;
- }
-
- if (wbc->sync_mode != WB_SYNC_NONE)
- wait_on_page_writeback(page);
-
- if (PageWriteback(page) ||
- !clear_page_dirty_for_io(page)) {
- unlock_page(page);
- break;
- }
-
- /*
- * This actually clears the dirty bit in the radix tree.
- * See cifs_writepage() for more commentary.
- */
- set_page_writeback(page);
- if (page_offset(page) >= i_size_read(mapping->host)) {
- *done = true;
- unlock_page(page);
- end_page_writeback(page);
- break;
- }
-
- wdata->pages[i] = page;
- *next = page->index + 1;
- ++nr_pages;
- }
-
- /* reset index to refind any pages skipped */
- if (nr_pages == 0)
- *index = wdata->pages[0]->index + 1;
-
- /* put any pages we aren't going to use */
- for (i = nr_pages; i < found_pages; i++) {
- put_page(wdata->pages[i]);
- wdata->pages[i] = NULL;
- }
-
- return nr_pages;
-}
-
-static int
-wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
- struct address_space *mapping, struct writeback_control *wbc)
-{
- int rc;
-
- wdata->sync_mode = wbc->sync_mode;
- wdata->nr_pages = nr_pages;
- wdata->offset = page_offset(wdata->pages[0]);
- wdata->pagesz = PAGE_SIZE;
- wdata->tailsz = min(i_size_read(mapping->host) -
- page_offset(wdata->pages[nr_pages - 1]),
- (loff_t)PAGE_SIZE);
- wdata->bytes = ((nr_pages - 1) * PAGE_SIZE) + wdata->tailsz;
- wdata->pid = wdata->cfile->pid;
-
- rc = adjust_credits(wdata->server, &wdata->credits, wdata->bytes);
- if (rc)
- return rc;
-
- if (wdata->cfile->invalidHandle)
- rc = -EAGAIN;
- else
- rc = wdata->server->ops->async_writev(wdata,
- cifs_writedata_release);
-
- return rc;
-}
-
-static int
-cifs_writepage_locked(struct page *page, struct writeback_control *wbc);
-
-static int cifs_write_one_page(struct page *page, struct writeback_control *wbc,
- void *data)
-{
- struct address_space *mapping = data;
- int ret;
-
- ret = cifs_writepage_locked(page, wbc);
- unlock_page(page);
- mapping_set_error(mapping, ret);
- return ret;
-}
-
-static int cifs_writepages(struct address_space *mapping,
- struct writeback_control *wbc)
-{
- struct inode *inode = mapping->host;
- struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
- struct TCP_Server_Info *server;
- bool done = false, scanned = false, range_whole = false;
- pgoff_t end, index;
- struct cifs_writedata *wdata;
- struct cifsFileInfo *cfile = NULL;
- int rc = 0;
- int saved_rc = 0;
- unsigned int xid;
-
- /*
- * If wsize is smaller than the page cache size, default to writing
- * one page at a time.
- */
- if (cifs_sb->ctx->wsize < PAGE_SIZE)
- return write_cache_pages(mapping, wbc, cifs_write_one_page,
- mapping);
-
- xid = get_xid();
- if (wbc->range_cyclic) {
- index = mapping->writeback_index; /* Start from prev offset */
- end = -1;
- } else {
- index = wbc->range_start >> PAGE_SHIFT;
- end = wbc->range_end >> PAGE_SHIFT;
- if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
- range_whole = true;
- scanned = true;
- }
- server = cifs_pick_channel(cifs_sb_master_tcon(cifs_sb)->ses);
-
-retry:
- while (!done && index <= end) {
- unsigned int i, nr_pages, found_pages, wsize;
- pgoff_t next = 0, tofind, saved_index = index;
- struct cifs_credits credits_on_stack;
- struct cifs_credits *credits = &credits_on_stack;
- int get_file_rc = 0;
-
- if (cfile)
- cifsFileInfo_put(cfile);
-
- rc = cifs_get_writable_file(CIFS_I(inode), FIND_WR_ANY, &cfile);
-
- /* in case of an error store it to return later */
- if (rc)
- get_file_rc = rc;
-
- rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->wsize,
- &wsize, credits);
- if (rc != 0) {
- done = true;
- break;
- }
-
- tofind = min((wsize / PAGE_SIZE) - 1, end - index) + 1;
-
- wdata = wdata_alloc_and_fillpages(tofind, mapping, end, &index,
- &found_pages);
- if (!wdata) {
- rc = -ENOMEM;
- done = true;
- add_credits_and_wake_if(server, credits, 0);
- break;
- }
-
- if (found_pages == 0) {
- kref_put(&wdata->refcount, cifs_writedata_release);
- add_credits_and_wake_if(server, credits, 0);
- break;
- }
-
- nr_pages = wdata_prepare_pages(wdata, found_pages, mapping, wbc,
- end, &index, &next, &done);
-
- /* nothing to write? */
- if (nr_pages == 0) {
- kref_put(&wdata->refcount, cifs_writedata_release);
- add_credits_and_wake_if(server, credits, 0);
- continue;
- }
-
- wdata->credits = credits_on_stack;
- wdata->cfile = cfile;
- wdata->server = server;
- cfile = NULL;
-
- if (!wdata->cfile) {
- cifs_dbg(VFS, "No writable handle in writepages rc=%d\n",
- get_file_rc);
- if (is_retryable_error(get_file_rc))
- rc = get_file_rc;
- else
- rc = -EBADF;
- } else
- rc = wdata_send_pages(wdata, nr_pages, mapping, wbc);
-
- for (i = 0; i < nr_pages; ++i)
- unlock_page(wdata->pages[i]);
-
- /* send failure -- clean up the mess */
- if (rc != 0) {
- add_credits_and_wake_if(server, &wdata->credits, 0);
- for (i = 0; i < nr_pages; ++i) {
- if (is_retryable_error(rc))
- redirty_page_for_writepage(wbc,
- wdata->pages[i]);
- else
- SetPageError(wdata->pages[i]);
- end_page_writeback(wdata->pages[i]);
- put_page(wdata->pages[i]);
- }
- if (!is_retryable_error(rc))
- mapping_set_error(mapping, rc);
- }
- kref_put(&wdata->refcount, cifs_writedata_release);
-
- if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN) {
- index = saved_index;
- continue;
- }
-
- /* Return immediately if we received a signal during writing */
- if (is_interrupt_error(rc)) {
- done = true;
- break;
- }
-
- if (rc != 0 && saved_rc == 0)
- saved_rc = rc;
-
- wbc->nr_to_write -= nr_pages;
- if (wbc->nr_to_write <= 0)
- done = true;
-
- index = next;
- }
-
- if (!scanned && !done) {
- /*
- * We hit the last page and there is more work to be done: wrap
- * back to the start of the file
- */
- scanned = true;
- index = 0;
- goto retry;
- }
-
- if (saved_rc != 0)
- rc = saved_rc;
-
- if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
- mapping->writeback_index = index;
-
- if (cfile)
- cifsFileInfo_put(cfile);
- free_xid(xid);
- /* Indication to update ctime and mtime as close is deferred */
- set_bit(CIFS_INO_MODIFIED_ATTR, &CIFS_I(inode)->flags);
- return rc;
-}
-#endif
-
/*
* Extend the region to be written back to include subsequent contiguously
* dirty pages if possible, but don't sleep while doing so.
@@ -3506,49 +3198,6 @@ int cifs_flush(struct file *file, fl_owner_t id)
return rc;
}
-#if 0 // TODO: Remove for iov_iter support
-static int
-cifs_write_allocate_pages(struct page **pages, unsigned long num_pages)
-{
- int rc = 0;
- unsigned long i;
-
- for (i = 0; i < num_pages; i++) {
- pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
- if (!pages[i]) {
- /*
- * save number of pages we have already allocated and
- * return with ENOMEM error
- */
- num_pages = i;
- rc = -ENOMEM;
- break;
- }
- }
-
- if (rc) {
- for (i = 0; i < num_pages; i++)
- put_page(pages[i]);
- }
- return rc;
-}
-
-static inline
-size_t get_numpages(const size_t wsize, const size_t len, size_t *cur_len)
-{
- size_t num_pages;
- size_t clen;
-
- clen = min_t(const size_t, len, wsize);
- num_pages = DIV_ROUND_UP(clen, PAGE_SIZE);
-
- if (cur_len)
- *cur_len = clen;
-
- return num_pages;
-}
-#endif
-
static void
cifs_uncached_writedata_release(struct kref *refcount)
{
@@ -3581,50 +3230,6 @@ cifs_uncached_writev_complete(struct work_struct *work)
kref_put(&wdata->refcount, cifs_uncached_writedata_release);
}
-#if 0 // TODO: Remove for iov_iter support
-static int
-wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
- size_t *len, unsigned long *num_pages)
-{
- size_t save_len, copied, bytes, cur_len = *len;
- unsigned long i, nr_pages = *num_pages;
-
- save_len = cur_len;
- for (i = 0; i < nr_pages; i++) {
- bytes = min_t(const size_t, cur_len, PAGE_SIZE);
- copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from);
- cur_len -= copied;
- /*
- * If we didn't copy as much as we expected, then that
- * may mean we trod into an unmapped area. Stop copying
- * at that point. On the next pass through the big
- * loop, we'll likely end up getting a zero-length
- * write and bailing out of it.
- */
- if (copied < bytes)
- break;
- }
- cur_len = save_len - cur_len;
- *len = cur_len;
-
- /*
- * If we have no data to send, then that probably means that
- * the copy above failed altogether. That's most likely because
- * the address in the iovec was bogus. Return -EFAULT and let
- * the caller free anything we allocated and bail out.
- */
- if (!cur_len)
- return -EFAULT;
-
- /*
- * i + 1 now represents the number of pages we actually used in
- * the copy phase above.
- */
- *num_pages = i + 1;
- return 0;
-}
-#endif
-
static int
cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
struct cifs_aio_ctx *ctx)
@@ -4211,83 +3816,6 @@ cifs_uncached_readv_complete(struct work_struct *work)
kref_put(&rdata->refcount, cifs_readdata_release);
}
-#if 0 // TODO: Remove for iov_iter support
-
-static int
-uncached_fill_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, struct iov_iter *iter,
- unsigned int len)
-{
- int result = 0;
- unsigned int i;
- unsigned int nr_pages = rdata->nr_pages;
- unsigned int page_offset = rdata->page_offset;
-
- rdata->got_bytes = 0;
- rdata->tailsz = PAGE_SIZE;
- for (i = 0; i < nr_pages; i++) {
- struct page *page = rdata->pages[i];
- size_t n;
- unsigned int segment_size = rdata->pagesz;
-
- if (i == 0)
- segment_size -= page_offset;
- else
- page_offset = 0;
-
-
- if (len <= 0) {
- /* no need to hold page hostage */
- rdata->pages[i] = NULL;
- rdata->nr_pages--;
- put_page(page);
- continue;
- }
-
- n = len;
- if (len >= segment_size)
- /* enough data to fill the page */
- n = segment_size;
- else
- rdata->tailsz = len;
- len -= n;
-
- if (iter)
- result = copy_page_from_iter(
- page, page_offset, n, iter);
-#ifdef CONFIG_CIFS_SMB_DIRECT
- else if (rdata->mr)
- result = n;
-#endif
- else
- result = cifs_read_page_from_socket(
- server, page, page_offset, n);
- if (result < 0)
- break;
-
- rdata->got_bytes += result;
- }
-
- return result != -ECONNABORTED && rdata->got_bytes > 0 ?
- rdata->got_bytes : result;
-}
-
-static int
-cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, unsigned int len)
-{
- return uncached_fill_pages(server, rdata, NULL, len);
-}
-
-static int
-cifs_uncached_copy_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata,
- struct iov_iter *iter)
-{
- return uncached_fill_pages(server, rdata, iter, iter->count);
-}
-#endif
-
static int cifs_resend_rdata(struct cifs_readdata *rdata,
struct list_head *rdata_list,
struct cifs_aio_ctx *ctx)
@@ -4897,140 +4425,6 @@ int cifs_file_mmap(struct file *file, struct vm_area_struct *vma)
return rc;
}
-#if 0 // TODO: Remove for iov_iter support
-
-static void
-cifs_readv_complete(struct work_struct *work)
-{
- unsigned int i, got_bytes;
- struct cifs_readdata *rdata = container_of(work,
- struct cifs_readdata, work);
-
- got_bytes = rdata->got_bytes;
- for (i = 0; i < rdata->nr_pages; i++) {
- struct page *page = rdata->pages[i];
-
- if (rdata->result == 0 ||
- (rdata->result == -EAGAIN && got_bytes)) {
- flush_dcache_page(page);
- SetPageUptodate(page);
- } else
- SetPageError(page);
-
- if (rdata->result == 0 ||
- (rdata->result == -EAGAIN && got_bytes))
- cifs_readpage_to_fscache(rdata->mapping->host, page);
-
- unlock_page(page);
-
- got_bytes -= min_t(unsigned int, PAGE_SIZE, got_bytes);
-
- put_page(page);
- rdata->pages[i] = NULL;
- }
- kref_put(&rdata->refcount, cifs_readdata_release);
-}
-
-static int
-readpages_fill_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, struct iov_iter *iter,
- unsigned int len)
-{
- int result = 0;
- unsigned int i;
- u64 eof;
- pgoff_t eof_index;
- unsigned int nr_pages = rdata->nr_pages;
- unsigned int page_offset = rdata->page_offset;
-
- /* determine the eof that the server (probably) has */
- eof = CIFS_I(rdata->mapping->host)->server_eof;
- eof_index = eof ? (eof - 1) >> PAGE_SHIFT : 0;
- cifs_dbg(FYI, "eof=%llu eof_index=%lu\n", eof, eof_index);
-
- rdata->got_bytes = 0;
- rdata->tailsz = PAGE_SIZE;
- for (i = 0; i < nr_pages; i++) {
- struct page *page = rdata->pages[i];
- unsigned int to_read = rdata->pagesz;
- size_t n;
-
- if (i == 0)
- to_read -= page_offset;
- else
- page_offset = 0;
-
- n = to_read;
-
- if (len >= to_read) {
- len -= to_read;
- } else if (len > 0) {
- /* enough for partial page, fill and zero the rest */
- zero_user(page, len + page_offset, to_read - len);
- n = rdata->tailsz = len;
- len = 0;
- } else if (page->index > eof_index) {
- /*
- * The VFS will not try to do readahead past the
- * i_size, but it's possible that we have outstanding
- * writes with gaps in the middle and the i_size hasn't
- * caught up yet. Populate those with zeroed out pages
- * to prevent the VFS from repeatedly attempting to
- * fill them until the writes are flushed.
- */
- zero_user(page, 0, PAGE_SIZE);
- flush_dcache_page(page);
- SetPageUptodate(page);
- unlock_page(page);
- put_page(page);
- rdata->pages[i] = NULL;
- rdata->nr_pages--;
- continue;
- } else {
- /* no need to hold page hostage */
- unlock_page(page);
- put_page(page);
- rdata->pages[i] = NULL;
- rdata->nr_pages--;
- continue;
- }
-
- if (iter)
- result = copy_page_from_iter(
- page, page_offset, n, iter);
-#ifdef CONFIG_CIFS_SMB_DIRECT
- else if (rdata->mr)
- result = n;
-#endif
- else
- result = cifs_read_page_from_socket(
- server, page, page_offset, n);
- if (result < 0)
- break;
-
- rdata->got_bytes += result;
- }
-
- return result != -ECONNABORTED && rdata->got_bytes > 0 ?
- rdata->got_bytes : result;
-}
-
-static int
-cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, unsigned int len)
-{
- return readpages_fill_pages(server, rdata, NULL, len);
-}
-
-static int
-cifs_readpages_copy_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata,
- struct iov_iter *iter)
-{
- return readpages_fill_pages(server, rdata, iter, iter->count);
-}
-#endif
-
/*
* Unlock a bunch of folios in the pagecache.
*/
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 10/11] cifs: DIO to/from KVEC-type iterators should now work
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (7 preceding siblings ...)
2023-02-10 23:32 ` [PATCH 09/11] cifs: Remove unused code David Howells
@ 2023-02-10 23:32 ` David Howells
2023-02-10 23:32 ` [PATCH 11/11] cifs: Fix problem with encrypted RDMA data read David Howells
2023-02-12 23:39 ` David Howells
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:32 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French
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 f3cedec9d22a..a5d54ae6aaa6 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3546,16 +3546,6 @@ 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;
@@ -4089,16 +4079,6 @@ 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;
^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 11/11] cifs: Fix problem with encrypted RDMA data read
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (8 preceding siblings ...)
2023-02-10 23:32 ` [PATCH 10/11] cifs: DIO to/from KVEC-type iterators should now work David Howells
@ 2023-02-10 23:32 ` David Howells
2023-02-12 23:39 ` David Howells
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-10 23:32 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel, Long Li,
Namjae Jeon
When the cifs client is talking to the ksmbd server by RDMA and the ksmbd
server has "smb3 encryption = yes" in its config file, the normal PDU
stream is encrypted, but the directly-delivered data isn't in the stream
(and isn't encrypted), but is rather delivered by DDP/RDMA packets (at
least with IWarp).
Currently, the direct delivery fails with:
buf can not contain only a part of read data
WARNING: CPU: 0 PID: 4619 at fs/cifs/smb2ops.c:4731 handle_read_data+0x393/0x405
...
RIP: 0010:handle_read_data+0x393/0x405
...
smb3_handle_read_data+0x30/0x37
receive_encrypted_standard+0x141/0x224
cifs_demultiplex_thread+0x21a/0x63b
kthread+0xe7/0xef
ret_from_fork+0x22/0x30
The problem apparently stemming from the fact that it's trying to manage
the decryption, but the data isn't in the smallbuf, the bigbuf or the page
array).
This can be fixed simply by inserting an extra case into handle_read_data()
that checks to see if use_rdma_mr is true, and if it is, just setting
rdata->got_bytes to the length of data delivered and allowing normal
continuation.
This can be seen in an IWarp packet trace. With the upstream code, it does
a DDP/RDMA packet, which produces the warning above and then retries,
retrieving the data inline, spread across several SMBDirect messages that
get glued together into a single PDU. With the patch applied, only the
DDP/RDMA packet is seen.
Note that this doesn't happen if the server isn't told to encrypt stuff and
it does also happen with softRoCE.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <smfrench@gmail.com>
cc: Tom Talpey <tom@talpey.com>
cc: Long Li <longli@microsoft.com>
cc: Namjae Jeon <linkinjeon@kernel.org>
cc: Stefan Metzmacher <metze@samba.org>
cc: linux-cifs@vger.kernel.org
Link: https://lore.kernel.org/r/166855224228.1998592.2212551359609792175.stgit@warthog.procyon.org.uk/ # v1
---
fs/cifs/smb2ops.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 744cd7374a43..636175850ca7 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4734,6 +4734,9 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
if (length < 0)
return length;
rdata->got_bytes = data_len;
+ } else if (use_rdma_mr) {
+ /* The data was delivered directly by RDMA. */
+ rdata->got_bytes = data_len;
} else {
/* read response payload cannot be in both buf and pages */
WARN_ONCE(1, "buf can not contain only a part of read data");
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH 11/11] cifs: Fix problem with encrypted RDMA data read
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
` (9 preceding siblings ...)
2023-02-10 23:32 ` [PATCH 11/11] cifs: Fix problem with encrypted RDMA data read David Howells
@ 2023-02-12 23:39 ` David Howells
10 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-12 23:39 UTC (permalink / raw)
To: Steve French
Cc: dhowells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel, Long Li,
Namjae Jeon
Sorry, this one shouldn't have been included. It's the one Stefan Metzmacher
objected to and provided his own changes for.
David
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator
2023-02-03 20:59 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
@ 2023-02-03 20:59 ` David Howells
0 siblings, 0 replies; 13+ messages in thread
From: David Howells @ 2023-02-03 20:59 UTC (permalink / raw)
To: Steve French
Cc: David Howells, Al Viro, Shyam Prasad N, Rohith Surabattula,
Tom Talpey, Stefan Metzmacher, Christoph Hellwig, Matthew Wilcox,
Jeff Layton, linux-cifs, linux-fsdevel, linux-kernel,
Steve French, linux-cachefs
Add a function to extract the pages from a user-space supplied iterator
(UBUF- or IOVEC-type) into a BVEC-type iterator, retaining the pages by
getting a pin on them (as FOLL_PIN) as we go.
This is useful in three situations:
(1) A userspace thread may have a sibling that unmaps or remaps the
process's VM during the operation, changing the assignment of the
pages and potentially causing an error. Retaining the pages keeps
some pages around, even if this occurs; futher, we find out at the
point of extraction if EFAULT is going to be incurred.
(2) Pages might get swapped out/discarded if not retained, so we want to
retain them to avoid the reload causing a deadlock due to a DIO
from/to an mmapped region on the same file.
(3) The iterator may get passed to sendmsg() by the filesystem. If a
fault occurs, we may get a short write to a TCP stream that's then
tricky to recover from.
We don't deal with other types of iterator here, leaving it to other
mechanisms to retain the pages (eg. PG_locked, PG_writeback and the pipe
lock).
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: linux-cachefs@redhat.com
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
fs/netfs/Makefile | 1 +
fs/netfs/iterator.c | 103 ++++++++++++++++++++++++++++++++++++++++++
include/linux/netfs.h | 4 ++
3 files changed, 108 insertions(+)
create mode 100644 fs/netfs/iterator.c
diff --git a/fs/netfs/Makefile b/fs/netfs/Makefile
index f684c0cd1ec5..386d6fb92793 100644
--- a/fs/netfs/Makefile
+++ b/fs/netfs/Makefile
@@ -3,6 +3,7 @@
netfs-y := \
buffered_read.o \
io.o \
+ iterator.o \
main.o \
objects.o
diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
new file mode 100644
index 000000000000..6f0d79080abc
--- /dev/null
+++ b/fs/netfs/iterator.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Iterator helpers.
+ *
+ * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/netfs.h>
+#include "internal.h"
+
+/**
+ * netfs_extract_user_iter - Extract the pages from a user iterator into a bvec
+ * @orig: The original iterator
+ * @orig_len: The amount of iterator to copy
+ * @new: The iterator to be set up
+ * @extraction_flags: Flags to qualify the request
+ *
+ * Extract the page fragments from the given amount of the source iterator and
+ * build up a second iterator that refers to all of those bits. This allows
+ * the original iterator to disposed of.
+ *
+ * @extraction_flags can have ITER_ALLOW_P2PDMA set to request peer-to-peer DMA be
+ * allowed on the pages extracted.
+ *
+ * On success, the number of elements in the bvec is returned, the original
+ * iterator will have been advanced by the amount extracted.
+ *
+ * The iov_iter_extract_mode() function should be used to query how cleanup
+ * should be performed.
+ */
+ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
+ struct iov_iter *new,
+ iov_iter_extraction_t extraction_flags)
+{
+ struct bio_vec *bv = NULL;
+ struct page **pages;
+ unsigned int cur_npages;
+ unsigned int max_pages;
+ unsigned int npages = 0;
+ unsigned int i;
+ ssize_t ret;
+ size_t count = orig_len, offset, len;
+ size_t bv_size, pg_size;
+
+ if (WARN_ON_ONCE(!iter_is_ubuf(orig) && !iter_is_iovec(orig)))
+ return -EIO;
+
+ max_pages = iov_iter_npages(orig, INT_MAX);
+ bv_size = array_size(max_pages, sizeof(*bv));
+ bv = kvmalloc(bv_size, GFP_KERNEL);
+ if (!bv)
+ return -ENOMEM;
+
+ /* Put the page list at the end of the bvec list storage. bvec
+ * elements are larger than page pointers, so as long as we work
+ * 0->last, we should be fine.
+ */
+ pg_size = array_size(max_pages, sizeof(*pages));
+ pages = (void *)bv + bv_size - pg_size;
+
+ while (count && npages < max_pages) {
+ ret = iov_iter_extract_pages(orig, &pages, count,
+ max_pages - npages, extraction_flags,
+ &offset);
+ if (ret < 0) {
+ pr_err("Couldn't get user pages (rc=%zd)\n", ret);
+ break;
+ }
+
+ if (ret > count) {
+ pr_err("get_pages rc=%zd more than %zu\n", ret, count);
+ break;
+ }
+
+ count -= ret;
+ ret += offset;
+ cur_npages = DIV_ROUND_UP(ret, PAGE_SIZE);
+
+ if (npages + cur_npages > max_pages) {
+ pr_err("Out of bvec array capacity (%u vs %u)\n",
+ npages + cur_npages, max_pages);
+ break;
+ }
+
+ for (i = 0; i < cur_npages; i++) {
+ len = ret > PAGE_SIZE ? PAGE_SIZE : ret;
+ bv[npages + i].bv_page = *pages++;
+ bv[npages + i].bv_offset = offset;
+ bv[npages + i].bv_len = len - offset;
+ ret -= len;
+ offset = 0;
+ }
+
+ npages += cur_npages;
+ }
+
+ iov_iter_bvec(new, orig->data_source, bv, npages, orig_len - count);
+ return npages;
+}
+EXPORT_SYMBOL_GPL(netfs_extract_user_iter);
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 4c76ddfb6a67..b11a84f6c32b 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -17,6 +17,7 @@
#include <linux/workqueue.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
+#include <linux/uio.h>
enum netfs_sreq_ref_trace;
@@ -296,6 +297,9 @@ void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
bool was_async, enum netfs_sreq_ref_trace what);
void netfs_stats_show(struct seq_file *);
+ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
+ struct iov_iter *new,
+ iov_iter_extraction_t extraction_flags);
/**
* netfs_inode - Get the netfs inode context from the inode
^ permalink raw reply related [flat|nested] 13+ messages in thread
end of thread, other threads:[~2023-02-12 23:40 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-02-10 23:31 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
2023-02-10 23:31 ` [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
2023-02-10 23:31 ` [PATCH 02/11] netfs: Add a function to extract an iterator into a scatterlist David Howells
2023-02-10 23:31 ` [PATCH 03/11] cifs: Add a function to build an RDMA SGE list from an iterator David Howells
2023-02-10 23:31 ` [PATCH 04/11] cifs: Add a function to Hash the contents of " David Howells
2023-02-10 23:31 ` [PATCH 05/11] cifs: Add some helper functions David Howells
2023-02-10 23:32 ` [PATCH 06/11] cifs: Add a function to read into an iter from a socket David Howells
2023-02-10 23:32 ` [PATCH 08/11] cifs: Build the RDMA SGE list directly from an iterator David Howells
2023-02-10 23:32 ` [PATCH 09/11] cifs: Remove unused code David Howells
2023-02-10 23:32 ` [PATCH 10/11] cifs: DIO to/from KVEC-type iterators should now work David Howells
2023-02-10 23:32 ` [PATCH 11/11] cifs: Fix problem with encrypted RDMA data read David Howells
2023-02-12 23:39 ` David Howells
-- strict thread matches above, loose matches on Subject: below --
2023-02-03 20:59 [PATCH 00/11] smb3: Use iov_iters down to the network transport and fix DIO page pinning David Howells
2023-02-03 20:59 ` [PATCH 01/11] netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator David Howells
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).