read() called twice for /proc files

[Tim Hockin <thockin@sun.com>]

woops!  sent too early!

Is there a general solution to the case of read() being called minimum
twice for a file in /proc?  I have a small file in /proc, whose data takes
a fair time to generate.  My read() handler gets called once for the data,
and once so I can return 0 to terminate read().

This results in the actual read taking twice as long.  Perhaps I am missing
something...

What if the proc generic stuff used file->private_data as an EOF flag.  It
seems really bizarre that the read loop loops until return 0 or eof is
set.  We promptly throw away the EOF information that the read() handler
set.

Would it break anything?  Is there something I am not seeing in the larger
picture?

-- 
Tim Hockin
Systems Software Engineer
Sun Microsystems, Cobalt Server Appliances
thockin@sun.com