Re: [PATCH[ udevd race conditions and performance, assorted cleanups

[Greg KH <greg@kroah.com>]

On Fri, Mar 26, 2004 at 11:48:15PM -0500, Chris Friesen wrote:
> 
> This patch covers a number of areas:
> 
> 1) sysfs.h is fixed up to use the common dbg() macro.  This fixes the 
> case where DEBUG is defined but USE_LOG isn't.
> 
> 2) udevstart.c is modified to include the proper headers, rather than 
> getting them indirectly which can break depending on Makefile flags
> 
> 3) udevd.c gets some major changes:
> a) I added a pipe from the signal handler.  This fixes the race 
> conditions that I mentioned earlier.  Basically, the point of the pipe 
> is to force the select() call to return immediately if a signal handler 
> fired before we actually started the select() call.  This then lets us 
> run the appropriate code based on flags set in the signal handler proper.
> b) I added a number of flags to coalesce calls to common routines.  This 
> should make things slightly more efficient.
> c) since most calls will tend to come in with a sequence number larger 
> than what has been received, I switched msg_queue_insert() to scan the 
> msg_list backwards to improve performance.
> 
> Comments?

Thanks for doing this, applied.

greg k-h


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