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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2007-07-15 23:41:47 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-16 09:05:51 -0700
commit35426128adaacf8cdabc2482598252d488b7ccb9 (patch)
tree492831903703126e883c9eb82c61f49e81c230fb
parentdb0ef08efa1bb94ba9a9e44c255d9058df5fde8d (diff)
downloadlinux-bcache-35426128adaacf8cdabc2482598252d488b7ccb9.tar.zst
genericserial: remove bogus optimisation check and dead code paths
We've been using the 'new locking' for a long time now so it seems pointless keeping the old one around. Remove it and undo the macros it uses back into real code for readability. Remove the bogus 'no termios change' checks. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Morten Helgesen <morten@sourcepoet.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/char/generic_serial.c120
1 files changed, 3 insertions, 117 deletions
diff --git a/drivers/char/generic_serial.c b/drivers/char/generic_serial.c
index 8ea02755b1c9..8facf3e25c49 100644
--- a/drivers/char/generic_serial.c
+++ b/drivers/char/generic_serial.c
@@ -43,16 +43,6 @@ static int gs_debug;
#define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __FUNCTION__)
#define func_exit() gs_dprintk (GS_DEBUG_FLOW, "gs: exit %s\n", __FUNCTION__)
-#define NEW_WRITE_LOCKING 1
-#if NEW_WRITE_LOCKING
-#define DECL /* Nothing */
-#define LOCKIT mutex_lock(& port->port_write_mutex);
-#define RELEASEIT mutex_unlock(&port->port_write_mutex);
-#else
-#define DECL unsigned long flags;
-#define LOCKIT save_flags (flags);cli ()
-#define RELEASEIT restore_flags (flags)
-#endif
#define RS_EVENT_WRITE_WAKEUP 1
@@ -62,7 +52,6 @@ module_param(gs_debug, int, 0644);
void gs_put_char(struct tty_struct * tty, unsigned char ch)
{
struct gs_port *port;
- DECL
func_enter ();
@@ -75,11 +64,11 @@ void gs_put_char(struct tty_struct * tty, unsigned char ch)
if (! (port->flags & ASYNC_INITIALIZED)) return;
/* Take a lock on the serial tranmit buffer! */
- LOCKIT;
+ mutex_lock(& port->port_write_mutex);
if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
/* Sorry, buffer is full, drop character. Update statistics???? -- REW */
- RELEASEIT;
+ mutex_unlock(&port->port_write_mutex);
return;
}
@@ -87,13 +76,11 @@ void gs_put_char(struct tty_struct * tty, unsigned char ch)
port->xmit_head &= SERIAL_XMIT_SIZE - 1;
port->xmit_cnt++; /* Characters in buffer */
- RELEASEIT;
+ mutex_unlock(&port->port_write_mutex);
func_exit ();
}
-#ifdef NEW_WRITE_LOCKING
-
/*
> Problems to take into account are:
> -1- Interrupts that empty part of the buffer.
@@ -166,90 +153,6 @@ int gs_write(struct tty_struct * tty,
func_exit ();
return total;
}
-#else
-/*
-> Problems to take into account are:
-> -1- Interrupts that empty part of the buffer.
-> -2- page faults on the access to userspace.
-> -3- Other processes that are also trying to do a "write".
-*/
-
-int gs_write(struct tty_struct * tty,
- const unsigned char *buf, int count)
-{
- struct gs_port *port;
- int c, total = 0;
- int t;
- unsigned long flags;
-
- func_enter ();
-
- /* The standard serial driver returns 0 in this case.
- That sounds to me as "No error, I just didn't get to writing any
- bytes. Feel free to try again."
- The "official" way to write n bytes from buf is:
-
- for (nwritten = 0;nwritten < n;nwritten += rv) {
- rv = write (fd, buf+nwritten, n-nwritten);
- if (rv < 0) break; // Error: bail out. //
- }
-
- which will loop endlessly in this case. The manual page for write
- agrees with me. In practise almost everybody writes
- "write (fd, buf,n);" but some people might have had to deal with
- incomplete writes in the past and correctly implemented it by now...
- */
-
- if (!tty) return -EIO;
-
- port = tty->driver_data;
- if (!port || !port->xmit_buf)
- return -EIO;
-
- local_save_flags(flags);
- while (1) {
- cli();
- c = count;
-
- /* This is safe because we "OWN" the "head". Noone else can
- change the "head": we own the port_write_mutex. */
- /* Don't overrun the end of the buffer */
- t = SERIAL_XMIT_SIZE - port->xmit_head;
- if (t < c) c = t;
-
- /* This is safe because the xmit_cnt can only decrease. This
- would increase "t", so we might copy too little chars. */
- /* Don't copy past the "head" of the buffer */
- t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
- if (t < c) c = t;
-
- /* Can't copy more? break out! */
- if (c <= 0) {
- local_restore_flags(flags);
- break;
- }
- memcpy(port->xmit_buf + port->xmit_head, buf, c);
- port->xmit_head = ((port->xmit_head + c) &
- (SERIAL_XMIT_SIZE-1));
- port->xmit_cnt += c;
- local_restore_flags(flags);
- buf += c;
- count -= c;
- total += c;
- }
-
- if (port->xmit_cnt &&
- !tty->stopped &&
- !tty->hw_stopped &&
- !(port->flags & GS_TX_INTEN)) {
- port->flags |= GS_TX_INTEN;
- port->rd->enable_tx_interrupts (port);
- }
- func_exit ();
- return total;
-}
-
-#endif
@@ -737,23 +640,6 @@ void gs_set_termios (struct tty_struct * tty,
gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
}
- /* This is an optimization that is only allowed for dumb cards */
- /* Smart cards require knowledge of iflags and oflags too: that
- might change hardware cooking mode.... */
- if (old_termios) {
- if( (tiosp->c_iflag == old_termios->c_iflag)
- && (tiosp->c_oflag == old_termios->c_oflag)
- && (tiosp->c_cflag == old_termios->c_cflag)
- && (tiosp->c_lflag == old_termios->c_lflag)
- && (tiosp->c_line == old_termios->c_line)
- && (memcmp(tiosp->c_cc, old_termios->c_cc, NCC) == 0)) {
- gs_dprintk(GS_DEBUG_TERMIOS, "gs_set_termios: optimized away\n");
- return /* 0 */;
- }
- } else
- gs_dprintk(GS_DEBUG_TERMIOS, "gs_set_termios: no old_termios: "
- "no optimization\n");
-
if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
if(tiosp->c_iflag != old_termios->c_iflag) printk("c_iflag changed\n");
if(tiosp->c_oflag != old_termios->c_oflag) printk("c_oflag changed\n");