[PATCH v2 04/22] netfs: Remove deprecated use of PG_private_2 as a second writeback flag

[David Howells <dhowells@redhat.com>]

Remove the deprecated use of PG_private_2 in netfslib.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
---
 fs/ceph/addr.c           |  19 +-----
 fs/netfs/buffered_read.c |   8 +--
 fs/netfs/io.c            | 144 ---------------------------------------
 3 files changed, 2 insertions(+), 169 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 18ddacb00511..74bfd10b1b1a 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -498,11 +498,6 @@ const struct netfs_request_ops ceph_netfs_ops = {
 };
 
 #ifdef CONFIG_CEPH_FSCACHE
-static void ceph_set_page_fscache(struct page *page)
-{
-	folio_start_private_2(page_folio(page)); /* [DEPRECATED] */
-}
-
 static void ceph_fscache_write_terminated(void *priv, ssize_t error, bool was_async)
 {
 	struct inode *inode = priv;
@@ -520,10 +515,6 @@ static void ceph_fscache_write_to_cache(struct inode *inode, u64 off, u64 len, b
 			       ceph_fscache_write_terminated, inode, true, caching);
 }
 #else
-static inline void ceph_set_page_fscache(struct page *page)
-{
-}
-
 static inline void ceph_fscache_write_to_cache(struct inode *inode, u64 off, u64 len, bool caching)
 {
 }
@@ -715,8 +706,6 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 		len = wlen;
 
 	set_page_writeback(page);
-	if (caching)
-		ceph_set_page_fscache(page);
 	ceph_fscache_write_to_cache(inode, page_off, len, caching);
 
 	if (IS_ENCRYPTED(inode)) {
@@ -800,8 +789,6 @@ static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 		return AOP_WRITEPAGE_ACTIVATE;
 	}
 
-	folio_wait_private_2(page_folio(page)); /* [DEPRECATED] */
-
 	err = writepage_nounlock(page, wbc);
 	if (err == -ERESTARTSYS) {
 		/* direct memory reclaimer was killed by SIGKILL. return 0
@@ -1075,8 +1062,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 				unlock_page(page);
 				break;
 			}
-			if (PageWriteback(page) ||
-			    PagePrivate2(page) /* [DEPRECATED] */) {
+			if (PageWriteback(page)) {
 				if (wbc->sync_mode == WB_SYNC_NONE) {
 					doutc(cl, "%p under writeback\n", page);
 					unlock_page(page);
@@ -1084,7 +1070,6 @@ static int ceph_writepages_start(struct address_space *mapping,
 				}
 				doutc(cl, "waiting on writeback %p\n", page);
 				wait_on_page_writeback(page);
-				folio_wait_private_2(page_folio(page)); /* [DEPRECATED] */
 			}
 
 			if (!clear_page_dirty_for_io(page)) {
@@ -1269,8 +1254,6 @@ static int ceph_writepages_start(struct address_space *mapping,
 			}
 
 			set_page_writeback(page);
-			if (caching)
-				ceph_set_page_fscache(page);
 			len += thp_size(page);
 		}
 		ceph_fscache_write_to_cache(inode, offset, len, caching);
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index b3fd6e1fa322..1622cce535a3 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -464,7 +464,7 @@ int netfs_write_begin(struct netfs_inode *ctx,
 	if (!netfs_is_cache_enabled(ctx) &&
 	    netfs_skip_folio_read(folio, pos, len, false)) {
 		netfs_stat(&netfs_n_rh_write_zskip);
-		goto have_folio_no_wait;
+		goto have_folio;
 	}
 
 	rreq = netfs_alloc_request(mapping, file,
@@ -505,12 +505,6 @@ int netfs_write_begin(struct netfs_inode *ctx,
 	netfs_put_request(rreq, false, netfs_rreq_trace_put_return);
 
 have_folio:
-	if (test_bit(NETFS_ICTX_USE_PGPRIV2, &ctx->flags)) {
-		ret = folio_wait_private_2_killable(folio);
-		if (ret < 0)
-			goto error;
-	}
-have_folio_no_wait:
 	*_folio = folio;
 	_leave(" = 0");
 	return 0;
diff --git a/fs/netfs/io.c b/fs/netfs/io.c
index 60a19f96e0ce..2641238aae82 100644
--- a/fs/netfs/io.c
+++ b/fs/netfs/io.c
@@ -98,146 +98,6 @@ static void netfs_rreq_completed(struct netfs_io_request *rreq, bool was_async)
 	netfs_put_request(rreq, was_async, netfs_rreq_trace_put_complete);
 }
 
-/*
- * [DEPRECATED] Deal with the completion of writing the data to the cache.  We
- * have to clear the PG_fscache bits on the folios involved and release the
- * caller's ref.
- *
- * May be called in softirq mode and we inherit a ref from the caller.
- */
-static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq,
-					  bool was_async)
-{
-	struct netfs_io_subrequest *subreq;
-	struct folio *folio;
-	pgoff_t unlocked = 0;
-	bool have_unlocked = false;
-
-	rcu_read_lock();
-
-	list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
-		XA_STATE(xas, &rreq->mapping->i_pages, subreq->start / PAGE_SIZE);
-
-		xas_for_each(&xas, folio, (subreq->start + subreq->len - 1) / PAGE_SIZE) {
-			if (xas_retry(&xas, folio))
-				continue;
-
-			/* We might have multiple writes from the same huge
-			 * folio, but we mustn't unlock a folio more than once.
-			 */
-			if (have_unlocked && folio->index <= unlocked)
-				continue;
-			unlocked = folio_next_index(folio) - 1;
-			trace_netfs_folio(folio, netfs_folio_trace_end_copy);
-			folio_end_private_2(folio);
-			have_unlocked = true;
-		}
-	}
-
-	rcu_read_unlock();
-	netfs_rreq_completed(rreq, was_async);
-}
-
-static void netfs_rreq_copy_terminated(void *priv, ssize_t transferred_or_error,
-				       bool was_async) /* [DEPRECATED] */
-{
-	struct netfs_io_subrequest *subreq = priv;
-	struct netfs_io_request *rreq = subreq->rreq;
-
-	if (IS_ERR_VALUE(transferred_or_error)) {
-		netfs_stat(&netfs_n_rh_write_failed);
-		trace_netfs_failure(rreq, subreq, transferred_or_error,
-				    netfs_fail_copy_to_cache);
-	} else {
-		netfs_stat(&netfs_n_rh_write_done);
-	}
-
-	trace_netfs_sreq(subreq, netfs_sreq_trace_write_term);
-
-	/* If we decrement nr_copy_ops to 0, the ref belongs to us. */
-	if (atomic_dec_and_test(&rreq->nr_copy_ops))
-		netfs_rreq_unmark_after_write(rreq, was_async);
-
-	netfs_put_subrequest(subreq, was_async, netfs_sreq_trace_put_terminated);
-}
-
-/*
- * [DEPRECATED] Perform any outstanding writes to the cache.  We inherit a ref
- * from the caller.
- */
-static void netfs_rreq_do_write_to_cache(struct netfs_io_request *rreq)
-{
-	struct netfs_cache_resources *cres = &rreq->cache_resources;
-	struct netfs_io_subrequest *subreq, *next, *p;
-	struct iov_iter iter;
-	int ret;
-
-	trace_netfs_rreq(rreq, netfs_rreq_trace_copy);
-
-	/* We don't want terminating writes trying to wake us up whilst we're
-	 * still going through the list.
-	 */
-	atomic_inc(&rreq->nr_copy_ops);
-
-	list_for_each_entry_safe(subreq, p, &rreq->subrequests, rreq_link) {
-		if (!test_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags)) {
-			list_del_init(&subreq->rreq_link);
-			netfs_put_subrequest(subreq, false,
-					     netfs_sreq_trace_put_no_copy);
-		}
-	}
-
-	list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
-		/* Amalgamate adjacent writes */
-		while (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) {
-			next = list_next_entry(subreq, rreq_link);
-			if (next->start != subreq->start + subreq->len)
-				break;
-			subreq->len += next->len;
-			list_del_init(&next->rreq_link);
-			netfs_put_subrequest(next, false,
-					     netfs_sreq_trace_put_merged);
-		}
-
-		ret = cres->ops->prepare_write(cres, &subreq->start, &subreq->len,
-					       subreq->len, rreq->i_size, true);
-		if (ret < 0) {
-			trace_netfs_failure(rreq, subreq, ret, netfs_fail_prepare_write);
-			trace_netfs_sreq(subreq, netfs_sreq_trace_write_skip);
-			continue;
-		}
-
-		iov_iter_xarray(&iter, ITER_SOURCE, &rreq->mapping->i_pages,
-				subreq->start, subreq->len);
-
-		atomic_inc(&rreq->nr_copy_ops);
-		netfs_stat(&netfs_n_rh_write);
-		netfs_get_subrequest(subreq, netfs_sreq_trace_get_copy_to_cache);
-		trace_netfs_sreq(subreq, netfs_sreq_trace_write);
-		cres->ops->write(cres, subreq->start, &iter,
-				 netfs_rreq_copy_terminated, subreq);
-	}
-
-	/* If we decrement nr_copy_ops to 0, the usage ref belongs to us. */
-	if (atomic_dec_and_test(&rreq->nr_copy_ops))
-		netfs_rreq_unmark_after_write(rreq, false);
-}
-
-static void netfs_rreq_write_to_cache_work(struct work_struct *work) /* [DEPRECATED] */
-{
-	struct netfs_io_request *rreq =
-		container_of(work, struct netfs_io_request, work);
-
-	netfs_rreq_do_write_to_cache(rreq);
-}
-
-static void netfs_rreq_write_to_cache(struct netfs_io_request *rreq) /* [DEPRECATED] */
-{
-	rreq->work.func = netfs_rreq_write_to_cache_work;
-	if (!queue_work(system_unbound_wq, &rreq->work))
-		BUG();
-}
-
 /*
  * Handle a short read.
  */
@@ -410,10 +270,6 @@ static void netfs_rreq_assess(struct netfs_io_request *rreq, bool was_async)
 	clear_bit_unlock(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
 	wake_up_bit(&rreq->flags, NETFS_RREQ_IN_PROGRESS);
 
-	if (test_bit(NETFS_RREQ_COPY_TO_CACHE, &rreq->flags) &&
-	    test_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags))
-		return netfs_rreq_write_to_cache(rreq);
-
 	netfs_rreq_completed(rreq, was_async);
 }