Re: [PATCH 12/23] initrd: switch initrd loading to struct file based APIs

Al Viro
2020-07-27T01:50:48Z

On Tue, Jul 14, 2020 at 09:04:16PM +0200, Christoph Hellwig wrote:

> static int __init
> -identify_ramdisk_image(int fd, int start_block, decompress_fn *decompressor)
> +identify_ramdisk_image(struct file *file, int start_block,
> + decompress_fn *decompressor)
> {
....
> - ksys_lseek(fd, start_block * BLOCK_SIZE, 0);
> kfree(buf);
> return nblocks;
> }

You do realize that you've changed behaviour of that thing if start_block != 0?
Old one used to leave the things for subsequent reads to start at start_block * 512;
new one will ignore that. So after

> - nblocks = identify_ramdisk_image(in_fd, rd_image_start, &decompressor);
> + nblocks = identify_ramdisk_image(in_file, rd_image_start, &decompressor);

you'll have in_file->f_pos left at 0 instead of rd_image_start * 512.

... affecting this

> - if (crd_load(in_fd, out_fd, decompressor) == 0)
> + if (crd_load(in_file, out_file, decompressor) == 0)

... and this

> - ksys_read(in_fd, buf, BLOCK_SIZE);
> - ksys_write(out_fd, buf, BLOCK_SIZE);
> + kernel_read(in_file, buf, BLOCK_SIZE, &in_file->f_pos);
> + kernel_write(out_file, buf, BLOCK_SIZE, &out_file->f_pos);

FWIW, I would suggest *not* bothering with ->f_pos and using two global
(well, file-static, obviously) variables instead. And kill 'pos' in
identify_ramdisk_image() as well - use the in_pos instead.