Re: [PATCH 7/11] 2.6.18-mm3 pktcdvd: make procfs interface optional

From: Peter Osterlund
Date: Thu Oct 05 2006 - 16:00:45 EST


"Thomas Maier" <balagi@xxxxxxxxxxx> writes:

> this patch makes the procfs interface optional and groups
> the procfs functions together.
> New kernel config parameter: CDROM_PKTCDVD_PROCINTF

Given the fact that Linus doesn't allow breaking user space tools
unless absolutely necessary, I don't think it makes sense to be able
to disable the character device control code.

The /proc/driver/pktcdvd/pktcdvd? file only contains debugging stuff
though, and the main reason it's not already in debugfs is that
debugfs didn't exist when Jens wrote this driver.

Therefore a patch that unconditionally moves
/proc/driver/pktcdvd/pktcdvd? to debugfs would make a lot of sense.

Also, the current change has another problem:

static int pkt_seq_show(struct seq_file *m, void *p)
+{
+ struct pktcdvd_device *pd = m->private;
+ char buf[1024];
+
+ pkt_print_info(pd, buf, sizeof(buf));
+ seq_printf(m, "%s", buf);
+ return 0;
+}

This wastes 1K stack space, and it can corrupt the stack if the
pkt_print_info() function wants to write more than 1K data.

Unconditionally moving to debugfs would remove the need for the
pkt_print_info() function so the buf array wouldn't be needed any
more.

--
Peter Osterlund - petero2@xxxxxxxxx
http://web.telia.com/~u89404340
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