Re: [PATCH 23/23] vfs: Teach readahead to use the file_hotplug_lock

Badari Pulavarty
2009-06-03T23:25:43Z

On Mon, 2009-06-01 at 14:50 -0700, Eric W. Biederman wrote:
> From: Eric W. Biederman <ebiederm@maxwell.aristanetworks.com>
>
> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
> ---
> mm/filemap.c | 25 ++++++++++++++++---------
> 1 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 379ff0b..5016aa5 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1402,16 +1402,23 @@ SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count)
>
> ret = -EBADF;
> file = fget(fd);
> - if (file) {
> - if (file->f_mode & FMODE_READ) {
> - struct address_space *mapping = file->f_mapping;
> - pgoff_t start = offset >> PAGE_CACHE_SHIFT;
> - pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
> - unsigned long len = end - start + 1;
> - ret = do_readahead(mapping, file, start, len);
> - }
> - fput(file);
> + if (!file)
> + goto out;
> +
> + if (!(file->f_mode & FMODE_READ))
> + goto out_fput;
> +

To be consistent with others, don't you want to do
ret = -EIO;
here ?
> + if (file_hotplug_read_trylock(file)) {
> + struct address_space *mapping = file->f_mapping;
> + pgoff_t start = offset >> PAGE_CACHE_SHIFT;
> + pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
> + unsigned long len = end - start + 1;
> + ret = do_readahead(mapping, file, start, len);
> + file_hotplug_read_unlock(file);
> }
> +out_fput:
> + fput(file);
> +out:
> return ret;
> }
> #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS

Thanks,
Badari