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serial: fix off by one errors
In zs_console_putchar() occurs: if (zs_transmit_drain(zport, irq)) write_zsdata(zport, ch); However if in zs_transmit_drain() no empty Tx Buffer occurs, limit reaches -1 => true, and the write still occurs. This patch changes postfix to prefix decrements in this and similar functions to prevent similar mistakes in the future. This decreases the iterations with one but the chosen loop count was arbitrary anyway. In sunhv limit reaches -1, not 0, so the test is off by one. Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Maciej W. Rozycki <macro@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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parent
607c268ef9
commit
52e3632ea6
3 changed files with 7 additions and 7 deletions
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@ -204,7 +204,7 @@ static int sbd_receive_drain(struct sbd_port *sport)
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{
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int loops = 10000;
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while (sbd_receive_ready(sport) && loops--)
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while (sbd_receive_ready(sport) && --loops)
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read_sbdchn(sport, R_DUART_RX_HOLD);
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return loops;
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}
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@ -218,7 +218,7 @@ static int __maybe_unused sbd_transmit_drain(struct sbd_port *sport)
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{
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int loops = 10000;
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while (!sbd_transmit_ready(sport) && loops--)
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while (!sbd_transmit_ready(sport) && --loops)
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udelay(2);
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return loops;
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}
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@ -232,7 +232,7 @@ static int sbd_line_drain(struct sbd_port *sport)
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{
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int loops = 10000;
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while (!sbd_transmit_empty(sport) && loops--)
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while (!sbd_transmit_empty(sport) && --loops)
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udelay(2);
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return loops;
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}
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@ -461,7 +461,7 @@ static void sunhv_console_write_paged(struct console *con, const char *s, unsign
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break;
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udelay(1);
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}
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if (limit <= 0)
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if (limit < 0)
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break;
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page_bytes -= written;
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ra += written;
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@ -231,7 +231,7 @@ static int zs_receive_drain(struct zs_port *zport)
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{
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int loops = 10000;
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while ((read_zsreg(zport, R0) & Rx_CH_AV) && loops--)
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while ((read_zsreg(zport, R0) & Rx_CH_AV) && --loops)
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read_zsdata(zport);
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return loops;
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}
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@ -241,7 +241,7 @@ static int zs_transmit_drain(struct zs_port *zport, int irq)
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struct zs_scc *scc = zport->scc;
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int loops = 10000;
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while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && loops--) {
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while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && --loops) {
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zs_spin_unlock_cond_irq(&scc->zlock, irq);
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udelay(2);
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zs_spin_lock_cond_irq(&scc->zlock, irq);
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@ -254,7 +254,7 @@ static int zs_line_drain(struct zs_port *zport, int irq)
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struct zs_scc *scc = zport->scc;
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int loops = 10000;
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while (!(read_zsreg(zport, R1) & ALL_SNT) && loops--) {
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while (!(read_zsreg(zport, R1) & ALL_SNT) && --loops) {
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zs_spin_unlock_cond_irq(&scc->zlock, irq);
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udelay(2);
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zs_spin_lock_cond_irq(&scc->zlock, irq);
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