| Date | Mon, 27 Jul 2020 03:55:07 +0100 | From | Al Viro <> | Subject | Re: [PATCH 17/23] initramfs: switch initramfs unpacking to struct file based APIs |
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On Tue, Jul 14, 2020 at 09:04:21PM +0200, Christoph Hellwig wrote:
> - ssize_t rv = ksys_write(fd, p, count); > + ssize_t rv = kernel_write(file, p, count, &file->f_pos);
No. Sure, that'll work for ramfs with nobody else playing with those. However, this is the wrong way to do such things; do *NOT* pass the address of file->f_pos to anything. The few places that still do that are wrong.
As a general rule, ->read() and ->write() instances should never be given &file->f_pos. Address of a local variable - sure, no problem. Copy it back into ->f_pos when they are done? Also fine. But not this,
Keep that offset in a variable (static in file, argument of xwrite(), whatever).
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