Commit bfaa33b8 authored by David Howells's avatar David Howells Committed by Christian Brauner

netfs: Provide an iterator-reset function

Provide a function to reset the iterator on a subrequest.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240814203850.2240469-17-dhowells@redhat.com/ # v2
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent cd0277ed
......@@ -69,6 +69,7 @@ int netfs_buffer_append_folio(struct netfs_io_request *rreq, struct folio *folio
bool needs_put);
struct folio_queue *netfs_delete_buffer_head(struct netfs_io_request *wreq);
void netfs_clear_buffer(struct netfs_io_request *rreq);
void netfs_reset_iter(struct netfs_io_subrequest *subreq);
/*
* objects.c
......@@ -161,9 +162,6 @@ struct netfs_io_request *netfs_create_write_req(struct address_space *mapping,
void netfs_reissue_write(struct netfs_io_stream *stream,
struct netfs_io_subrequest *subreq,
struct iov_iter *source);
int netfs_advance_write(struct netfs_io_request *wreq,
struct netfs_io_stream *stream,
loff_t start, size_t len, bool to_eof);
struct netfs_io_request *netfs_begin_writethrough(struct kiocb *iocb, size_t len);
int netfs_advance_writethrough(struct netfs_io_request *wreq, struct writeback_control *wbc,
struct folio *folio, size_t copied, bool to_page_end,
......
......@@ -84,6 +84,24 @@ void netfs_clear_buffer(struct netfs_io_request *rreq)
}
}
/*
* Reset the subrequest iterator to refer just to the region remaining to be
* read. The iterator may or may not have been advanced by socket ops or
* extraction ops to an extent that may or may not match the amount actually
* read.
*/
void netfs_reset_iter(struct netfs_io_subrequest *subreq)
{
struct iov_iter *io_iter = &subreq->io_iter;
size_t remain = subreq->len - subreq->transferred;
if (io_iter->count > remain)
iov_iter_advance(io_iter, io_iter->count - remain);
else if (io_iter->count < remain)
iov_iter_revert(io_iter, remain - io_iter->count);
iov_iter_truncate(&subreq->io_iter, remain);
}
/**
* netfs_dirty_folio - Mark folio dirty and pin a cache object for writeback
* @mapping: The mapping the folio belongs to.
......
......@@ -226,9 +226,8 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
/* Determine the set of buffers we're going to use. Each
* subreq gets a subset of a single overall contiguous buffer.
*/
netfs_reset_iter(from);
source = from->io_iter;
iov_iter_revert(&source, subreq->len - source.count);
iov_iter_advance(&source, from->transferred);
source.count = len;
/* Work through the sublist. */
......
......@@ -261,7 +261,7 @@ static void netfs_issue_write(struct netfs_io_request *wreq,
* we can avoid overrunning the credits obtained (cifs) and try to parallelise
* content-crypto preparation with network writes.
*/
int netfs_advance_write(struct netfs_io_request *wreq,
static int netfs_advance_write(struct netfs_io_request *wreq,
struct netfs_io_stream *stream,
loff_t start, size_t len, bool to_eof)
{
......
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