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Date: Thu, 22 Dec 2022 15:43:54 +0100
From: "Fabio M. De Francesco" <fmdefrancesco@...il.com>
To: Ira Weiny <ira.weiny@...el.com>
Cc: Evgeniy Dushistov <dushistov@...l.ru>,
Al Viro <viro@...iv.linux.org.uk>,
linux-kernel@...r.kernel.org, bpf@...r.kernel.org,
linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v4 2/3] fs/ufs: Change the signature of ufs_get_page()
On giovedì 22 dicembre 2022 06:13:43 CET Ira Weiny wrote:
> On Wed, Dec 21, 2022 at 06:28:01PM +0100, Fabio M. De Francesco wrote:
> > Change the signature of ufs_get_page() in order to prepare this function
> > to the conversion to the use of kmap_local_page(). Change also those call
> > sites which are required to conform its invocations to the new
> > signature.
> >
> > Cc: Ira Weiny <ira.weiny@...el.com>
> > Suggested-by: Al Viro <viro@...iv.linux.org.uk>
> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
> > ---
> >
> > fs/ufs/dir.c | 49 +++++++++++++++++++++----------------------------
> > 1 file changed, 21 insertions(+), 28 deletions(-)
> >
> > diff --git a/fs/ufs/dir.c b/fs/ufs/dir.c
> > index 69f78583c9c1..9fa86614d2d1 100644
> > --- a/fs/ufs/dir.c
> > +++ b/fs/ufs/dir.c
> > @@ -185,7 +185,7 @@ static bool ufs_check_page(struct page *page)
> >
> > return false;
> >
> > }
> >
> > -static struct page *ufs_get_page(struct inode *dir, unsigned long n)
> > +static void *ufs_get_page(struct inode *dir, unsigned long n, struct page
> > **p)>
> > {
> >
> > struct address_space *mapping = dir->i_mapping;
> > struct page *page = read_mapping_page(mapping, n, NULL);
> >
> > @@ -195,8 +195,10 @@ static struct page *ufs_get_page(struct inode *dir,
> > unsigned long n)>
> > if (!ufs_check_page(page))
> >
> > goto fail;
> >
> > }
> >
> > + *p = page;
> > + return page_address(page);
> >
> > }
> >
> > - return page;
> > + return ERR_CAST(page);
> >
> > fail:
> > ufs_put_page(page);
> >
> > @@ -227,15 +229,12 @@ ufs_next_entry(struct super_block *sb, struct
> > ufs_dir_entry *p)>
> > struct ufs_dir_entry *ufs_dotdot(struct inode *dir, struct page **p)
> > {
> >
> > - struct page *page = ufs_get_page(dir, 0);
> > - struct ufs_dir_entry *de = NULL;
> > + struct ufs_dir_entry *de = ufs_get_page(dir, 0, p);
>
> I don't know why but ufs_get_page() returning an address read really odd to
> me. But rolling around my head alternative names nothing seems better than
> this.
ufs_get_kaddr()?
> > - if (!IS_ERR(page)) {
> > - de = ufs_next_entry(dir->i_sb,
> > - (struct ufs_dir_entry
*)page_address(page));
> > - *p = page;
> > - }
> > - return de;
> > + if (!IS_ERR(de))
> > + return ufs_next_entry(dir->i_sb, de);
> > + else
> > + return NULL;
> >
> > }
> >
> > /*
> >
> > @@ -273,11 +272,10 @@ struct ufs_dir_entry *ufs_find_entry(struct inode
> > *dir, const struct qstr *qstr,>
> > start = 0;
> >
> > n = start;
> > do {
> >
> > - char *kaddr;
> > - page = ufs_get_page(dir, n);
> > - if (!IS_ERR(page)) {
> > - kaddr = page_address(page);
> > - de = (struct ufs_dir_entry *) kaddr;
> > + char *kaddr = ufs_get_page(dir, n, &page);
> > +
> > + if (!IS_ERR(kaddr)) {
> > + de = (struct ufs_dir_entry *)kaddr;
> >
> > kaddr += ufs_last_byte(dir, n) - reclen;
> > while ((char *) de <= kaddr) {
> >
> > if (ufs_match(sb, namelen, name, de))
> >
> > @@ -328,12 +326,10 @@ int ufs_add_link(struct dentry *dentry, struct inode
> > *inode)>
> > for (n = 0; n <= npages; n++) {
> >
> > char *dir_end;
> >
> > - page = ufs_get_page(dir, n);
> > - err = PTR_ERR(page);
> > - if (IS_ERR(page))
> > - goto out;
> > + kaddr = ufs_get_page(dir, n, &page);
> > + if (IS_ERR(kaddr))
> > + return PTR_ERR(kaddr);
> >
> > lock_page(page);
> >
> > - kaddr = page_address(page);
> >
> > dir_end = kaddr + ufs_last_byte(dir, n);
> > de = (struct ufs_dir_entry *)kaddr;
> > kaddr += PAGE_SIZE - reclen;
> >
> > @@ -395,7 +391,6 @@ int ufs_add_link(struct dentry *dentry, struct inode
> > *inode)>
> > /* OFFSET_CACHE */
> >
> > out_put:
> > ufs_put_page(page);
> >
> > -out:
> > return err;
> >
> > out_unlock:
> > unlock_page(page);
> >
> > @@ -429,6 +424,7 @@ ufs_readdir(struct file *file, struct dir_context
*ctx)
> >
> > unsigned chunk_mask = ~(UFS_SB(sb)->s_uspi->s_dirblksize - 1);
> > bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
> > unsigned flags = UFS_SB(sb)->s_flags;
> >
> > + struct page *page;
>
> NIT: Does page now leave the scope of the for loop?
>
Strange...
I can't say why I did so.
> > UFSD("BEGIN\n");
> >
> > @@ -439,16 +435,14 @@ ufs_readdir(struct file *file, struct dir_context
> > *ctx)
> >
> > char *kaddr, *limit;
> > struct ufs_dir_entry *de;
>
> Couldn't that be declared here?
Yes, it could :-)
> Regardless I don't think this is broken.
Since I have to submit a new version of this series, there's no problem moving
the declaration of "page" back into the loop.
> Reviewed-by: Ira Weiny <ira.weiny@...el.com>
Thanks,
Fabio
>
> > - struct page *page = ufs_get_page(inode, n);
> > -
> > - if (IS_ERR(page)) {
> > + kaddr = ufs_get_page(inode, n, &page);
> > + if (IS_ERR(kaddr)) {
> >
> > ufs_error(sb, __func__,
> >
> > "bad page in #%lu",
> > inode->i_ino);
> >
> > ctx->pos += PAGE_SIZE - offset;
> > return -EIO;
> >
> > }
> >
> > - kaddr = page_address(page);
> >
> > if (unlikely(need_revalidate)) {
> >
> > if (offset) {
> >
> > offset = ufs_validate_entry(sb, kaddr,
offset, chunk_mask);
> >
> > @@ -595,12 +589,11 @@ int ufs_empty_dir(struct inode * inode)
> >
> > for (i = 0; i < npages; i++) {
> >
> > char *kaddr;
> > struct ufs_dir_entry *de;
> >
> > - page = ufs_get_page(inode, i);
> >
> > - if (IS_ERR(page))
> > + kaddr = ufs_get_page(inode, i, &page);
> > + if (IS_ERR(kaddr))
> >
> > continue;
> >
> > - kaddr = page_address(page);
> >
> > de = (struct ufs_dir_entry *)kaddr;
> > kaddr += ufs_last_byte(inode, i) - UFS_DIR_REC_LEN(1);
> >
> > --
> > 2.39.0
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