Re: [PATCH v2] fs: ocfs2: Adding new return type vm_fault_t

From: Souptick Joarder
Date: Wed May 30 2018 - 07:40:12 EST


On Wed, May 23, 2018 at 9:02 PM, Souptick Joarder <jrdr.linux@xxxxxxxxx> wrote:
> Use new return type vm_fault_t for fault handler. For
> now, this is just documenting that the function returns
> a VM_FAULT value rather than an errno. Once all instances
> are converted, vm_fault_t will become a distinct type.
>
> Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")
>
> vmf_error() is the newly introduce inline function
> in 4.18.
>
> Fix one checkpatch.pl warning by replacing BUG_ON()
> with WARN_ON()
>
> Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
> Reviewed-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> ---
> fs/ocfs2/mmap.c | 44 ++++++++++++++++++++------------------------
> 1 file changed, 20 insertions(+), 24 deletions(-)
>
> diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
> index fb9a20e..036177e 100644
> --- a/fs/ocfs2/mmap.c
> +++ b/fs/ocfs2/mmap.c
> @@ -44,11 +44,11 @@
> #include "ocfs2_trace.h"
>
>
> -static int ocfs2_fault(struct vm_fault *vmf)
> +static vm_fault_t ocfs2_fault(struct vm_fault *vmf)
> {
> struct vm_area_struct *vma = vmf->vma;
> sigset_t oldset;
> - int ret;
> + vm_fault_t ret;
>
> ocfs2_block_signals(&oldset);
> ret = filemap_fault(vmf);
> @@ -59,10 +59,11 @@ static int ocfs2_fault(struct vm_fault *vmf)
> return ret;
> }
>
> -static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
> - struct page *page)
> +static vm_fault_t __ocfs2_page_mkwrite(struct file *file,
> + struct buffer_head *di_bh, struct page *page)
> {
> - int ret = VM_FAULT_NOPAGE;
> + int err;
> + vm_fault_t ret = VM_FAULT_NOPAGE;
> struct inode *inode = file_inode(file);
> struct address_space *mapping = inode->i_mapping;
> loff_t pos = page_offset(page);
> @@ -105,15 +106,12 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
> if (page->index == last_index)
> len = ((size - 1) & ~PAGE_MASK) + 1;
>
> - ret = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_MMAP,
> + err = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_MMAP,
> &locked_page, &fsdata, di_bh, page);
> - if (ret) {
> - if (ret != -ENOSPC)
> - mlog_errno(ret);
> - if (ret == -ENOMEM)
> - ret = VM_FAULT_OOM;
> - else
> - ret = VM_FAULT_SIGBUS;
> + if (err) {
> + if (err != -ENOSPC)
> + mlog_errno(err);
> + ret = vmf_error(err);
> goto out;
> }
>
> @@ -121,20 +119,21 @@ static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
> ret = VM_FAULT_NOPAGE;
> goto out;
> }
> - ret = ocfs2_write_end_nolock(mapping, pos, len, len, fsdata);
> - BUG_ON(ret != len);
> + err = ocfs2_write_end_nolock(mapping, pos, len, len, fsdata);
> + WARN_ON(err != len);
> ret = VM_FAULT_LOCKED;
> out:
> return ret;
> }
>
> -static int ocfs2_page_mkwrite(struct vm_fault *vmf)
> +static vm_fault_t ocfs2_page_mkwrite(struct vm_fault *vmf)
> {
> struct page *page = vmf->page;
> struct inode *inode = file_inode(vmf->vma->vm_file);
> struct buffer_head *di_bh = NULL;
> sigset_t oldset;
> - int ret;
> + int err;
> + vm_fault_t ret;
>
> sb_start_pagefault(inode->i_sb);
> ocfs2_block_signals(&oldset);
> @@ -144,13 +143,10 @@ static int ocfs2_page_mkwrite(struct vm_fault *vmf)
> * node. Taking the data lock will also ensure that we don't
> * attempt page truncation as part of a downconvert.
> */
> - ret = ocfs2_inode_lock(inode, &di_bh, 1);
> - if (ret < 0) {
> - mlog_errno(ret);
> - if (ret == -ENOMEM)
> - ret = VM_FAULT_OOM;
> - else
> - ret = VM_FAULT_SIGBUS;
> + err = ocfs2_inode_lock(inode, &di_bh, 1);
> + if (err < 0) {
> + mlog_errno(err);
> + ret = vmf_error(err);
> goto out;
> }
>
> --
> 1.9.1
>

Any comment for this patch ? We would like to
get this patch in queue for 4.18.