Re: [PATCH] mm: do_generic_file_read() never gets a NULL 'filp'argument

From: Andrew Morton
Date: Mon Sep 22 2008 - 04:33:57 EST


On Mon, 22 Sep 2008 11:46:10 +0530 Krishna Kumar <krkumar2@xxxxxxxxxx> wrote:

> From: Krishna Kumar <krkumar2@xxxxxxxxxx>
>
> The 'filp' argument to do_generic_file_read() is never NULL.
>

How did you verify this?

NFS used to like passing NULL file*'s into VFS functions. I don't
recall whether it affected do_generic_file_read().

> mm/filemap.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff -ruNp 2.6.27-rc7-org/mm/filemap.c 2.6.27-rc7-new/mm/filemap.c
> --- 2.6.27-rc7-org/mm/filemap.c 2008-09-17 12:53:25.000000000 +0530
> +++ 2.6.27-rc7-new/mm/filemap.c 2008-09-17 12:53:59.000000000 +0530
> @@ -1186,8 +1186,7 @@ out:
> ra->prev_pos |= prev_offset;
>
> *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset;
> - if (filp)
> - file_accessed(filp);
> + file_accessed(filp);
> }
>
> int file_read_actor(read_descriptor_t *desc, struct page *page,
--
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