[PATCH v4 08/12] nfs: drop usage of folio_file_pos

[Kairui Song]

From: Kairui Song <kasong@xxxxxxxxxxx>

folio_file_pos is only needed for mixed usage of page cache and
swap cache, for pure page cache usage, the caller can just use
folio_pos instead.

After commit e1209d3a7a67 ("mm: introduce ->swap_rw and use it for
reads from SWP_FS_OPS swap-space"), swap cache should never be exposed
to nfs.

So remove the usage of folio_file_pos in following NFS functions / helpers:

- nfs_vm_page_mkwrite

  It's only used by nfs_file_vm_ops.page_mkwrite

- trace event helper: nfs_folio_event
- trace event helper: nfs_folio_event_done

  These two are used through DEFINE_NFS_FOLIO_EVENT and
  DEFINE_NFS_FOLIO_EVENT_DONE, which defined following events:

  - trace_nfs_aop_readpage{_done}: only called by nfs_read_folio
  - trace_nfs_writeback_folio: only called by nfs_wb_folio
  - trace_nfs_invalidate_folio: only called by nfs_invalidate_folio
  - trace_nfs_launder_folio_done: only called by nfs_launder_folio

  None of them could possibly be used on swap cache folio,
  nfs_read_folio only called by:
  .write_begin -> nfs_read_folio
  .read_folio

  nfs_wb_folio only called by nfs mapping:
  .release_folio -> nfs_wb_folio
  .launder_folio -> nfs_wb_folio
  .write_begin -> nfs_read_folio -> nfs_wb_folio
  .read_folio -> nfs_wb_folio
  .write_end -> nfs_update_folio -> nfs_writepage_setup -> nfs_setup_write_request -> nfs_try_to_update_request -> nfs_wb_folio
  .page_mkwrite -> nfs_update_folio -> nfs_writepage_setup -> nfs_setup_write_request -> nfs_try_to_update_request -> nfs_wb_folio
  .write_begin -> nfs_flush_incompatible -> nfs_wb_folio
  .page_mkwrite -> nfs_vm_page_mkwrite -> nfs_flush_incompatible -> nfs_wb_folio

  nfs_invalidate_folio is only called by .invalidate_folio.
  nfs_launder_folio is only called by .launder_folio

- nfs_grow_file
- nfs_update_folio

  nfs_grow_file is only called by nfs_update_folio, and all
  possible callers of them are:

  .write_end -> nfs_update_folio
  .page_mkwrite -> nfs_update_folio

- nfs_wb_folio_cancel

  .invalidate_folio -> nfs_wb_folio_cancel

Also, seeing from the swap side, swap_rw is now the only interface calling
into fs, the offset info is always in iocb.ki_pos now.

So we can remove all these folio_file_pos call safely.

Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Cc: Anna Schumaker <anna@xxxxxxxxxx>
Cc: linux-nfs@xxxxxxxxxxxxxxx
---
 fs/nfs/file.c     | 2 +-
 fs/nfs/nfstrace.h | 4 ++--
 fs/nfs/write.c    | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 407c6e15afe2..02741c32e114 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -588,7 +588,7 @@ static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
 
 	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
 		 filp, filp->f_mapping->host->i_ino,
-		 (long long)folio_file_pos(folio));
+		 (long long)folio_pos(folio));
 
 	sb_start_pagefault(inode->i_sb);
 
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index afedb449b54f..d249741452e1 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -960,7 +960,7 @@ DECLARE_EVENT_CLASS(nfs_folio_event,
 			__entry->fileid = nfsi->fileid;
 			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
 			__entry->version = inode_peek_iversion_raw(inode);
-			__entry->offset = folio_file_pos(folio);
+			__entry->offset = folio_pos(folio);
 			__entry->count = nfs_folio_length(folio);
 		),
 
@@ -1008,7 +1008,7 @@ DECLARE_EVENT_CLASS(nfs_folio_event_done,
 			__entry->fileid = nfsi->fileid;
 			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
 			__entry->version = inode_peek_iversion_raw(inode);
-			__entry->offset = folio_file_pos(folio);
+			__entry->offset = folio_pos(folio);
 			__entry->count = nfs_folio_length(folio);
 			__entry->ret = ret;
 		),
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 5de85d725fb9..fc782d889449 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -281,7 +281,7 @@ static void nfs_grow_file(struct folio *folio, unsigned int offset,
 	end_index = ((i_size - 1) >> folio_shift(folio)) << folio_order(folio);
 	if (i_size > 0 && folio_index(folio) < end_index)
 		goto out;
-	end = folio_file_pos(folio) + (loff_t)offset + (loff_t)count;
+	end = folio_pos(folio) + (loff_t)offset + (loff_t)count;
 	if (i_size >= end)
 		goto out;
 	trace_nfs_size_grow(inode, end);
@@ -1362,7 +1362,7 @@ int nfs_update_folio(struct file *file, struct folio *folio,
 	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 
 	dprintk("NFS:       nfs_update_folio(%pD2 %d@%lld)\n", file, count,
-		(long long)(folio_file_pos(folio) + offset));
+		(long long)(folio_pos(folio) + offset));
 
 	if (!count)
 		goto out;
@@ -2073,7 +2073,7 @@ int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
  */
 int nfs_wb_folio(struct inode *inode, struct folio *folio)
 {
-	loff_t range_start = folio_file_pos(folio);
+	loff_t range_start = folio_pos(folio);
 	loff_t range_end = range_start + (loff_t)folio_size(folio) - 1;
 	struct writeback_control wbc = {
 		.sync_mode = WB_SYNC_ALL,
-- 
2.44.0