From: Ivo Sieben Date: Mon, 28 Jan 2013 12:32:01 +0000 (+0100) Subject: tty: Use raw spin lock to protect the TTY read section X-Git-Tag: v3.9-rc1~125^2~37 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=98001214c0436c2b697d696fde3696d32620d394;p=pandora-kernel.git tty: Use raw spin lock to protect the TTY read section The "normal" spin lock that guards the N_TTY line discipline read section is replaced by a raw spin lock. On a PREEMP_RT system this prevents unwanted scheduling overhead when data is read at the same time as data is being received: while RX IRQ threaded handling is busy a TTY read call is performed from a RT priority > threaded IRQ priority. The read call tries to take the read section spin lock (held by the threaded IRQ) which blocks and causes a context switch to/from the threaded IRQ handler until the spin lock is unlocked. Signed-off-by: Ivo Sieben Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed