From: Paul Fulghum Allow receive and write_wakeup callbacks to be called at hard interrupt context and/or with interrupts disabled (removes softirq warning). This mirrors changes by Paul Mackerras to ppp_async.c for the same purpose. Patch has been previously posted for comments and has been tested with success by multiple persons. Signed-off-by: Andrew Morton --- 25-akpm/drivers/net/ppp_synctty.c | 161 +++++++++++++++++++++----------------- 1 files changed, 92 insertions(+), 69 deletions(-) diff -puN drivers/net/ppp_synctty.c~ppp_syncttyc-receive-write_wakeup-fix drivers/net/ppp_synctty.c --- 25/drivers/net/ppp_synctty.c~ppp_syncttyc-receive-write_wakeup-fix Wed Jun 16 14:45:10 2004 +++ 25-akpm/drivers/net/ppp_synctty.c Wed Jun 16 14:45:10 2004 @@ -29,7 +29,7 @@ * PPP driver, written by Michael Callahan and Al Longyear, and * subsequently hacked by Paul Mackerras. * - * ==FILEVERSION 20020125== + * ==FILEVERSION 20040616== */ #include @@ -65,7 +65,9 @@ struct syncppp { struct sk_buff *tpkt; unsigned long last_xmit; - struct sk_buff *rpkt; + struct sk_buff_head rqueue; + + struct tasklet_struct tsk; atomic_t refcnt; struct semaphore dead_sem; @@ -88,6 +90,7 @@ static struct sk_buff* ppp_sync_txmunge( static int ppp_sync_send(struct ppp_channel *chan, struct sk_buff *skb); static int ppp_sync_ioctl(struct ppp_channel *chan, unsigned int cmd, unsigned long arg); +static void ppp_sync_process(unsigned long arg); static int ppp_sync_push(struct syncppp *ap); static void ppp_sync_flush_output(struct syncppp *ap); static void ppp_sync_input(struct syncppp *ap, const unsigned char *buf, @@ -217,6 +220,9 @@ ppp_sync_open(struct tty_struct *tty) ap->xaccm[3] = 0x60000000U; ap->raccm = ~0U; + skb_queue_head_init(&ap->rqueue); + tasklet_init(&ap->tsk, ppp_sync_process, (unsigned long) ap); + atomic_set(&ap->refcnt, 1); init_MUTEX_LOCKED(&ap->dead_sem); @@ -267,10 +273,10 @@ ppp_sync_close(struct tty_struct *tty) */ if (!atomic_dec_and_test(&ap->refcnt)) down(&ap->dead_sem); + tasklet_kill(&ap->tsk); ppp_unregister_channel(&ap->chan); - if (ap->rpkt != 0) - kfree_skb(ap->rpkt); + skb_queue_purge(&ap->rqueue); if (ap->tpkt != 0) kfree_skb(ap->tpkt); kfree(ap); @@ -369,17 +375,24 @@ ppp_sync_room(struct tty_struct *tty) return 65535; } +/* + * This can now be called from hard interrupt level as well + * as soft interrupt level or mainline. + */ static void ppp_sync_receive(struct tty_struct *tty, const unsigned char *buf, - char *flags, int count) + char *cflags, int count) { struct syncppp *ap = sp_get(tty); + unsigned long flags; if (ap == 0) return; - spin_lock_bh(&ap->recv_lock); - ppp_sync_input(ap, buf, flags, count); - spin_unlock_bh(&ap->recv_lock); + spin_lock_irqsave(&ap->recv_lock, flags); + ppp_sync_input(ap, buf, cflags, count); + spin_unlock_irqrestore(&ap->recv_lock, flags); + if (skb_queue_len(&ap->rqueue)) + tasklet_schedule(&ap->tsk); sp_put(ap); if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) && tty->driver->unthrottle) @@ -394,8 +407,8 @@ ppp_sync_wakeup(struct tty_struct *tty) clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); if (ap == 0) return; - if (ppp_sync_push(ap)) - ppp_output_wakeup(&ap->chan); + set_bit(XMIT_WAKEUP, &ap->xmit_flags); + tasklet_schedule(&ap->tsk); sp_put(ap); } @@ -449,9 +462,9 @@ ppp_sync_ioctl(struct ppp_channel *chan, if (get_user(val, (int *) arg)) break; ap->flags = val & ~SC_RCV_BITS; - spin_lock_bh(&ap->recv_lock); + spin_lock_irq(&ap->recv_lock); ap->rbits = val & SC_RCV_BITS; - spin_unlock_bh(&ap->recv_lock); + spin_unlock_irq(&ap->recv_lock); err = 0; break; @@ -512,6 +525,32 @@ ppp_sync_ioctl(struct ppp_channel *chan, } /* + * This is called at softirq level to deliver received packets + * to the ppp_generic code, and to tell the ppp_generic code + * if we can accept more output now. + */ +static void ppp_sync_process(unsigned long arg) +{ + struct syncppp *ap = (struct syncppp *) arg; + struct sk_buff *skb; + + /* process received packets */ + while ((skb = skb_dequeue(&ap->rqueue)) != NULL) { + if (skb->len == 0) { + /* zero length buffers indicate error */ + ppp_input_error(&ap->chan, 0); + kfree_skb(skb); + } + else + ppp_input(&ap->chan, skb); + } + + /* try to push more stuff out */ + if (test_bit(XMIT_WAKEUP, &ap->xmit_flags) && ppp_sync_push(ap)) + ppp_output_wakeup(&ap->chan); +} + +/* * Procedures for encapsulation and framing. */ @@ -600,7 +639,6 @@ ppp_sync_push(struct syncppp *ap) struct tty_struct *tty = ap->tty; int tty_stuffed = 0; - set_bit(XMIT_WAKEUP, &ap->xmit_flags); if (!spin_trylock_bh(&ap->xmit_lock)) return 0; for (;;) { @@ -667,15 +705,44 @@ ppp_sync_flush_output(struct syncppp *ap * Receive-side routines. */ -static inline void -process_input_packet(struct syncppp *ap) +/* called when the tty driver has data for us. + * + * Data is frame oriented: each call to ppp_sync_input is considered + * a whole frame. If the 1st flag byte is non-zero then the whole + * frame is considered to be in error and is tossed. + */ +static void +ppp_sync_input(struct syncppp *ap, const unsigned char *buf, + char *flags, int count) { struct sk_buff *skb; unsigned char *p; - int code = 0; - skb = ap->rpkt; - ap->rpkt = 0; + if (count == 0) + return; + + if (ap->flags & SC_LOG_INPKT) + ppp_print_buffer ("receive buffer", buf, count); + + /* stuff the chars in the skb */ + if ((skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2)) == 0) { + printk(KERN_ERR "PPPsync: no memory (input pkt)\n"); + goto err; + } + /* Try to get the payload 4-byte aligned */ + if (buf[0] != PPP_ALLSTATIONS) + skb_reserve(skb, 2 + (buf[0] & 1)); + + if (flags != 0 && *flags) { + /* error flag set, ignore frame */ + goto err; + } else if (count > skb_tailroom(skb)) { + /* packet overflowed MRU */ + goto err; + } + + p = skb_put(skb, count); + memcpy(p, buf, count); /* strip address/control field if present */ p = skb->data; @@ -693,59 +760,15 @@ process_input_packet(struct syncppp *ap) } else if (skb->len < 2) goto err; - /* pass to generic layer */ - ppp_input(&ap->chan, skb); + /* queue the frame to be processed */ + skb_queue_tail(&ap->rqueue, skb); return; - err: - kfree_skb(skb); - ppp_input_error(&ap->chan, code); -} - -/* called when the tty driver has data for us. - * - * Data is frame oriented: each call to ppp_sync_input is considered - * a whole frame. If the 1st flag byte is non-zero then the whole - * frame is considered to be in error and is tossed. - */ -static void -ppp_sync_input(struct syncppp *ap, const unsigned char *buf, - char *flags, int count) -{ - struct sk_buff *skb; - unsigned char *sp; - - if (count == 0) - return; - - /* if flag set, then error, ignore frame */ - if (flags != 0 && *flags) { - ppp_input_error(&ap->chan, *flags); - return; - } - - if (ap->flags & SC_LOG_INPKT) - ppp_print_buffer ("receive buffer", buf, count); - - /* stuff the chars in the skb */ - if ((skb = ap->rpkt) == 0) { - if ((skb = dev_alloc_skb(ap->mru + PPP_HDRLEN + 2)) == 0) { - printk(KERN_ERR "PPPsync: no memory (input pkt)\n"); - ppp_input_error(&ap->chan, 0); - return; - } - /* Try to get the payload 4-byte aligned */ - if (buf[0] != PPP_ALLSTATIONS) - skb_reserve(skb, 2 + (buf[0] & 1)); - ap->rpkt = skb; - } - if (count > skb_tailroom(skb)) { - /* packet overflowed MRU */ - ppp_input_error(&ap->chan, 1); - } else { - sp = skb_put(skb, count); - memcpy(sp, buf, count); - process_input_packet(ap); +err: + /* queue zero length packet as error indication */ + if (skb || (skb = dev_alloc_skb(0))) { + skb_trim(skb, 0); + skb_queue_tail(&ap->rqueue, skb); } } _