Messages in this thread | | | Date | Fri, 23 Jun 2006 08:41:20 -0500 | From | Paul Fulghum <> | Subject | Re: [PATCH][RFC] kill TTY_DONT_FLIP |
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Alan Cox wrote: > Looks good to me on a first review.
I looked at the paths taken by n_tty_receive_buf() for how they would effect read_chan():
* tty state (put_tty_queue,eraser,finish_erasing,etc) * read wakeups * start_tty/stop_tty * put_char/opost
everything looks OK without TTY_DONT_FLIP
2.0.X relied on the BKL (and dinosaurs roamed the Earth)
2.1.X introduced TTY_DONT_FLIP to prevent read_chan and n_tty_receive_buf from executing at the same time.
2.2.15 added tty->read_lock around the N_TTY read buffer, which is the only thing needing protection in this context.
The usual progression to finer grained locking. This looks like a safe removal.
The review also revealed a spot in reset_buffer_flags() where tty->read_lock needs to be extended around modifications of canon_head, canon_data, and read_flags. I'll make a patch for that.
-- Paul Fulghum Microgate Systems, Ltd. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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