From c0438174e8272d23fe43a5d3f23d777f5b412e87 Mon Sep 17 00:00:00 2001 From: Ralf Baechle DL5RB Date: Wed, 10 Aug 2005 10:03:20 -0700 Subject: [PATCH] [PATCH] 6pack persistence fix Fix the p-persistence CSMA algorithm which in simplex mode was starting with a slottime delay before doing anything else as if there was carrier collision resulting in bad performance on simplex links. Signed-off-by: Ralf Baechle DL5RB Acked-by: Jeff Garzik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/net/hamradio/6pack.c | 20 ++++---------------- 1 file changed, 4 insertions(+), 16 deletions(-) diff --git a/drivers/net/hamradio/6pack.c b/drivers/net/hamradio/6pack.c index e44f8e9055e..f9e3be96963 100644 --- a/drivers/net/hamradio/6pack.c +++ b/drivers/net/hamradio/6pack.c @@ -130,12 +130,11 @@ struct sixpack { #define AX25_6PACK_HEADER_LEN 0 -static void sp_start_tx_timer(struct sixpack *); static void sixpack_decode(struct sixpack *, unsigned char[], int); static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); /* - * perform the persistence/slottime algorithm for CSMA access. If the + * Perform the persistence/slottime algorithm for CSMA access. If the * persistence check was successful, write the data to the serial driver. * Note that in case of DAMA operation, the data is not sent here. */ @@ -143,7 +142,7 @@ static int encode_sixpack(unsigned char *, unsigned char *, int, unsigned char); static void sp_xmit_on_air(unsigned long channel) { struct sixpack *sp = (struct sixpack *) channel; - int actual; + int actual, when = sp->slottime; static unsigned char random; random = random * 17 + 41; @@ -159,20 +158,10 @@ static void sp_xmit_on_air(unsigned long channel) sp->tty->driver->write(sp->tty, &sp->led_state, 1); sp->status2 = 0; } else - sp_start_tx_timer(sp); + mod_timer(&sp->tx_t, jiffies + ((when + 1) * HZ) / 100); } /* ----> 6pack timer interrupt handler and friends. <---- */ -static void sp_start_tx_timer(struct sixpack *sp) -{ - int when = sp->slottime; - - del_timer(&sp->tx_t); - sp->tx_t.data = (unsigned long) sp; - sp->tx_t.function = sp_xmit_on_air; - sp->tx_t.expires = jiffies + ((when + 1) * HZ) / 100; - add_timer(&sp->tx_t); -} /* Encapsulate one AX.25 frame and stuff into a TTY queue. */ static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) @@ -243,8 +232,7 @@ static void sp_encaps(struct sixpack *sp, unsigned char *icp, int len) sp->xleft = count; sp->xhead = sp->xbuff; sp->status2 = count; - if (sp->duplex == 0) - sp_start_tx_timer(sp); + sp_xmit_on_air((unsigned long)sp); } return; -- 2.41.1