lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 9 Mar 2010 10:14:13 -0500 (EST)
From:	Alan Stern <stern@...land.harvard.edu>
To:	Jason Wessel <jason.wessel@...driver.com>
cc:	gregkh@...e.de, <linux-usb@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Alan Cox <alan@...ux.intel.com>,
	Oliver Neukum <oliver@...kum.org>
Subject: Re: [PATCH 4/6] usb-serial: optimize sysrq function calls

On Tue, 9 Mar 2010, Jason Wessel wrote:

> There is no need to have external function calls for the sysrq
> functions.  The compiler can inline the sysrq calls such that they are
> entirely a NOP if CONFIG_MAGIC_SYSRQ is not set.

This is not the best way to do what you want.  Keep 
usb_serial_handle_sysrq_char() and usb_serial_handle_break() as 
out-of-line routines in generic.c, but make them conditional on 
CONFIG_MAGIC_SYSRQ.  Then in the header file, depending on whether or 
not CONFIG_MAGIC_SYSRQ is defined, either put the usual extern function 
declarations or else put do-nothing inline definitions.

The advantage of keeping the functions out-of-line is the reduced
amount of code space (since the bodies aren't replicated every place
they get used).  This way you keep that advantage while still getting
the NOP implementation if CONFIG_MAGIC_SYSRQ isn't set.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ