Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752021Ab3GXMag (ORCPT ); Wed, 24 Jul 2013 08:30:36 -0400 Received: from mailout02.c08.mtsvc.net ([205.186.168.190]:56219 "EHLO mailout02.c08.mtsvc.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750863Ab3GXMad (ORCPT ); Wed, 24 Jul 2013 08:30:33 -0400 From: Peter Hurley To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Jiri Slaby , Peter Hurley Subject: [PATCH v3 6/9] n_tty: Remove overflow tests from receive_buf() path Date: Wed, 24 Jul 2013 08:29:54 -0400 Message-Id: <1374668997-29726-6-git-send-email-peter@hurleysoftware.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1374668997-29726-1-git-send-email-peter@hurleysoftware.com> References: <20130724001259.GA9239@kroah.com> <1374668997-29726-1-git-send-email-peter@hurleysoftware.com> X-Authenticated-User: 125194 peter@hurleysoftware.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5226 Lines: 188 Always pre-figure the space available in the read_buf and limit the inbound receive request to that amount. For compatibility reasons with the non-flow-controlled interface, n_tty_receive_buf() will continue filling read_buf until all data has been received or receive_room() returns 0. Signed-off-by: Peter Hurley --- drivers/tty/n_tty.c | 85 +++++++++++++++++++++++------------------------------ 1 file changed, 37 insertions(+), 48 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index aed1e94..0f33e0c 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -315,12 +315,9 @@ static inline void n_tty_check_unthrottle(struct tty_struct *tty) * not active. */ -static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) +static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) { - if (read_cnt(ldata) < N_TTY_BUF_SIZE) { - *read_buf_addr(ldata, ldata->read_head) = c; - ldata->read_head++; - } + *read_buf_addr(ldata, ldata->read_head++) = c; } /** @@ -1332,11 +1329,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) return; } if (c == '\n') { - if (read_cnt(ldata) >= N_TTY_BUF_SIZE) { - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } if (L_ECHO(tty) || L_ECHONL(tty)) { echo_char_raw('\n', ldata); commit_echoes(tty); @@ -1344,8 +1336,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) goto handle_newline; } if (c == EOF_CHAR(tty)) { - if (read_cnt(ldata) >= N_TTY_BUF_SIZE) - return; c = __DISABLED_CHAR; goto handle_newline; } @@ -1353,11 +1343,6 @@ n_tty_receive_char_special(struct tty_struct *tty, unsigned char c) (c == EOL2_CHAR(tty) && L_IEXTEN(tty))) { parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; - if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk)) { - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } /* * XXX are EOL_CHAR and EOL2_CHAR echoed?!? */ @@ -1387,12 +1372,6 @@ handle_newline: } parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; - if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { - /* beep if no space */ - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } if (L_ECHO(tty)) { finish_erasing(ldata); if (c == '\n') @@ -1431,14 +1410,6 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) start_tty(tty); process_echoes(tty); } - - parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; - if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - parmrk - 1)) { - /* beep if no space */ - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } if (L_ECHO(tty)) { finish_erasing(ldata); /* Record the column of first canon char. */ @@ -1447,6 +1418,7 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c) echo_char(c, tty); commit_echoes(tty); } + parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; if (parmrk) put_tty_queue(c, ldata); put_tty_queue(c, ldata); @@ -1475,13 +1447,6 @@ n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c) start_tty(tty); process_echoes(tty); } - - if (read_cnt(ldata) >= (N_TTY_BUF_SIZE - 1)) { - /* beep if no space */ - if (L_ECHO(tty)) - process_output('\a', tty); - return; - } if (L_ECHO(tty)) { finish_erasing(ldata); /* Record the column of first canon char. */ @@ -1690,8 +1655,23 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp, static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) { + int room, n; + down_read(&tty->termios_rwsem); - __receive_buf(tty, cp, fp, count); + + while (1) { + room = receive_room(tty); + n = min(count, room); + if (!n) + break; + __receive_buf(tty, cp, fp, n); + cp += n; + if (fp) + fp += n; + count -= n; + } + + tty->receive_room = room; n_tty_check_throttle(tty); up_read(&tty->termios_rwsem); } @@ -1700,22 +1680,31 @@ static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) { struct n_tty_data *ldata = tty->disc_data; - int room; + int room, n, rcvd = 0; down_read(&tty->termios_rwsem); - tty->receive_room = room = receive_room(tty); - if (!room) - ldata->no_room = 1; - count = min(count, room); - if (count) { - __receive_buf(tty, cp, fp, count); - n_tty_check_throttle(tty); + while (1) { + room = receive_room(tty); + n = min(count, room); + if (!n) { + if (!room) + ldata->no_room = 1; + break; + } + __receive_buf(tty, cp, fp, n); + cp += n; + if (fp) + fp += n; + count -= n; + rcvd += n; } + tty->receive_room = room; + n_tty_check_throttle(tty); up_read(&tty->termios_rwsem); - return count; + return rcvd; } int is_ignored(int sig) -- 1.8.1.2 -- 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/