[PATCH 5/7] nfs: fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests

Christoph Hellwig
2024-07-01T05:27:25Z

Fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests to
prepare for future changes to this code, and move the helpers to write.c
as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/nfs/pagelist.c | 77 ----------------------------------------
fs/nfs/write.c | 67 ++++++++++++++++++++++++++++++++--
include/linux/nfs_page.h | 1 -
3 files changed, 64 insertions(+), 81 deletions(-)

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index e48cc69a2361aa..fa7971072900b3 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -187,83 +187,6 @@ nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
}
EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);

-/*
- * nfs_unroll_locks - unlock all newly locked reqs and wait on @req
- * @head: head request of page group, must be holding head lock
- * @req: request that couldn't lock and needs to wait on the req bit lock
- *
- * This is a helper function for nfs_lock_and_join_requests
- * returns 0 on success, < 0 on error.
- */
-static void
-nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
-{
- struct nfs_page *tmp;
-
- /* relinquish all the locks successfully grabbed this run */
- for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
- if (!kref_read(&tmp->wb_kref))
- continue;
- nfs_unlock_and_release_request(tmp);
- }
-}
-
-/*
- * nfs_page_group_lock_subreq - try to lock a subrequest
- * @head: head request of page group
- * @subreq: request to lock
- *
- * This is a helper function for nfs_lock_and_join_requests which
- * must be called with the head request and page group both locked.
- * On error, it returns with the page group unlocked.
- */
-static int
-nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
-{
- int ret;
-
- if (!kref_get_unless_zero(&subreq->wb_kref))
- return 0;
- while (!nfs_lock_request(subreq)) {
- nfs_page_group_unlock(head);
- ret = nfs_wait_on_request(subreq);
- if (!ret)
- ret = nfs_page_group_lock(head);
- if (ret < 0) {
- nfs_unroll_locks(head, subreq);
- nfs_release_request(subreq);
- return ret;
- }
- }
- return 0;
-}
-
-/*
- * nfs_page_group_lock_subrequests - try to lock the subrequests
- * @head: head request of page group
- *
- * This is a helper function for nfs_lock_and_join_requests which
- * must be called with the head request locked.
- */
-int nfs_page_group_lock_subrequests(struct nfs_page *head)
-{
- struct nfs_page *subreq;
- int ret;
-
- ret = nfs_page_group_lock(head);
- if (ret < 0)
- return ret;
- /* lock each request in the page group */
- for (subreq = head->wb_this_page; subreq != head;
- subreq = subreq->wb_this_page) {
- ret = nfs_page_group_lock_subreq(head, subreq);
- if (ret < 0)
- return ret;
- }
- nfs_page_group_unlock(head);
- return 0;
-}
-
/*
* nfs_page_set_headlock - set the request PG_HEADLOCK
* @req: request that is to be locked
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 2b139493168d87..3ba298ebb0be14 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -476,6 +476,57 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
}

+/*
+ * nfs_unroll_locks - unlock all newly locked reqs and wait on @req
+ * @head: head request of page group, must be holding head lock
+ * @req: request that couldn't lock and needs to wait on the req bit lock
+ *
+ * This is a helper function for nfs_lock_and_join_requests
+ * returns 0 on success, < 0 on error.
+ */
+static void
+nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req)
+{
+ struct nfs_page *tmp;
+
+ /* relinquish all the locks successfully grabbed this run */
+ for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) {
+ if (!kref_read(&tmp->wb_kref))
+ continue;
+ nfs_unlock_and_release_request(tmp);
+ }
+}
+
+/*
+ * nfs_page_group_lock_subreq - try to lock a subrequest
+ * @head: head request of page group
+ * @subreq: request to lock
+ *
+ * This is a helper function for nfs_lock_and_join_requests which
+ * must be called with the head request and page group both locked.
+ * On error, it returns with the page group unlocked.
+ */
+static int
+nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq)
+{
+ int ret;
+
+ if (!kref_get_unless_zero(&subreq->wb_kref))
+ return 0;
+ while (!nfs_lock_request(subreq)) {
+ nfs_page_group_unlock(head);
+ ret = nfs_wait_on_request(subreq);
+ if (!ret)
+ ret = nfs_page_group_lock(head);
+ if (ret < 0) {
+ nfs_unroll_locks(head, subreq);
+ nfs_release_request(subreq);
+ return ret;
+ }
+ }
+ return 0;
+}
+
/*
* nfs_lock_and_join_requests - join all subreqs to the head req
* @folio: the folio used to lookup the "page group" of nfs_page structures
@@ -494,7 +545,7 @@ void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)
{
struct inode *inode = folio->mapping->host;
- struct nfs_page *head;
+ struct nfs_page *head, *subreq;
struct nfs_commit_info cinfo;
int ret;

@@ -524,11 +575,21 @@ static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)
if (ret < 0)
goto out_unlock;

- /* lock each request in the page group */
- ret = nfs_page_group_lock_subrequests(head);
+ ret = nfs_page_group_lock(head);
if (ret < 0)
goto out_unlock;

+ /* lock each request in the page group */
+ for (subreq = head->wb_this_page;
+ subreq != head;
+ subreq = subreq->wb_this_page) {
+ ret = nfs_page_group_lock_subreq(head, subreq);
+ if (ret < 0)
+ goto out_unlock;
+ }
+
+ nfs_page_group_unlock(head);
+
nfs_init_cinfo_from_inode(&cinfo, inode);
nfs_join_page_group(head, &cinfo, inode);
return head;
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index e799d93626f117..63eed97a18ade9 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -155,7 +155,6 @@ extern size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
extern int nfs_wait_on_request(struct nfs_page *);
extern void nfs_unlock_request(struct nfs_page *req);
extern void nfs_unlock_and_release_request(struct nfs_page *);
-extern int nfs_page_group_lock_subrequests(struct nfs_page *head);
extern void nfs_join_page_group(struct nfs_page *head,
struct nfs_commit_info *cinfo,
struct inode *inode);
--
2.43.0