n_tty: Fix PARMRK over-throttling

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If PARMRK is enabled, the available read buffer space computation is
overly-pessimistic, which results in severely throttled i/o, even
in the absence of parity errors. For example, if the 4k read buffer
contains 1k processed data, the input worker will compute available
space of 333 bytes, despite 3k being available. At 1365 chars of
processed data, 0 space available is computed.

*Divide remaining space* by 3, truncating down (if left == 2, left = 0).

Reported-by: Christian Riesch <christian.riesch@omicron.at>

Conflicts:
	drivers/tty/n_tty.c

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Peter Hurley 2015-01-16 15:05:38 -05:00 • committed by Greg Kroah-Hartman

parent 70aca71f92

commit 06c49f9fa3

1 changed files with 4 additions and 8 deletions

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drivers/tty/n_tty.c

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