![Takashi Iwai](/assets/img/avatar_default.png)
A kernel WARNING in snd_rawmidi_transmit_ack() is triggered by syzkaller fuzzer: WARNING: CPU: 1 PID: 20739 at sound/core/rawmidi.c:1136 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82999e2d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 [<ffffffff81352089>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482 [<ffffffff813522b9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515 [<ffffffff84f80bd5>] snd_rawmidi_transmit_ack+0x275/0x400 sound/core/rawmidi.c:1136 [<ffffffff84fdb3c1>] snd_virmidi_output_trigger+0x4b1/0x5a0 sound/core/seq/seq_virmidi.c:163 [< inline >] snd_rawmidi_output_trigger sound/core/rawmidi.c:150 [<ffffffff84f87ed9>] snd_rawmidi_kernel_write1+0x549/0x780 sound/core/rawmidi.c:1223 [<ffffffff84f89fd3>] snd_rawmidi_write+0x543/0xb30 sound/core/rawmidi.c:1273 [<ffffffff817b0323>] __vfs_write+0x113/0x480 fs/read_write.c:528 [<ffffffff817b1db7>] vfs_write+0x167/0x4a0 fs/read_write.c:577 [< inline >] SYSC_write fs/read_write.c:624 [<ffffffff817b50a1>] SyS_write+0x111/0x220 fs/read_write.c:616 [<ffffffff86336c36>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 Also a similar warning is found but in another path: Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82be2c0d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 [<ffffffff81355139>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482 [<ffffffff81355369>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515 [<ffffffff8527e69a>] rawmidi_transmit_ack+0x24a/0x3b0 sound/core/rawmidi.c:1133 [<ffffffff8527e851>] snd_rawmidi_transmit_ack+0x51/0x80 sound/core/rawmidi.c:1163 [<ffffffff852d9046>] snd_virmidi_output_trigger+0x2b6/0x570 sound/core/seq/seq_virmidi.c:185 [< inline >] snd_rawmidi_output_trigger sound/core/rawmidi.c:150 [<ffffffff85285a0b>] snd_rawmidi_kernel_write1+0x4bb/0x760 sound/core/rawmidi.c:1252 [<ffffffff85287b73>] snd_rawmidi_write+0x543/0xb30 sound/core/rawmidi.c:1302 [<ffffffff817ba5f3>] __vfs_write+0x113/0x480 fs/read_write.c:528 [<ffffffff817bc087>] vfs_write+0x167/0x4a0 fs/read_write.c:577 [< inline >] SYSC_write fs/read_write.c:624 [<ffffffff817bf371>] SyS_write+0x111/0x220 fs/read_write.c:616 [<ffffffff86660276>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 In the former case, the reason is that virmidi has an open code calling snd_rawmidi_transmit_ack() with the value calculated outside the spinlock. We may use snd_rawmidi_transmit() in a loop just for consuming the input data, but even there, there is a race between snd_rawmidi_transmit_peek() and snd_rawmidi_tranmit_ack(). Similarly in the latter case, it calls snd_rawmidi_transmit_peek() and snd_rawmidi_tranmit_ack() separately without protection, so they are racy as well. The patch tries to address these issues by the following ways: - Introduce the unlocked versions of snd_rawmidi_transmit_peek() and snd_rawmidi_transmit_ack() to be called inside the explicit lock. - Rewrite snd_rawmidi_transmit() to be race-free (the former case). - Make the split calls (the latter case) protected in the rawmidi spin lock. BugLink: http://lkml.kernel.org/r/CACT4Y+YPq1+cYLkadwjWa5XjzF1_Vki1eHnVn-Lm0hzhSpu5PA@mail.gmail.com BugLink: http://lkml.kernel.org/r/CACT4Y+acG4iyphdOZx47Nyq_VHGbpJQK-6xNpiqUjaZYqsXOGw@mail.gmail.com Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
555 lines
14 KiB
C
555 lines
14 KiB
C
/*
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* Virtual Raw MIDI client on Sequencer
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*
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* Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,
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* Jaroslav Kysela <perex@perex.cz>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/*
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* Virtual Raw MIDI client
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*
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* The virtual rawmidi client is a sequencer client which associate
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* a rawmidi device file. The created rawmidi device file can be
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* accessed as a normal raw midi, but its MIDI source and destination
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* are arbitrary. For example, a user-client software synth connected
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* to this port can be used as a normal midi device as well.
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*
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* The virtual rawmidi device accepts also multiple opens. Each file
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* has its own input buffer, so that no conflict would occur. The drain
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* of input/output buffer acts only to the local buffer.
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*
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*/
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#include <linux/init.h>
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#include <linux/wait.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <sound/core.h>
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#include <sound/rawmidi.h>
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#include <sound/info.h>
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#include <sound/control.h>
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#include <sound/minors.h>
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#include <sound/seq_kernel.h>
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#include <sound/seq_midi_event.h>
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#include <sound/seq_virmidi.h>
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MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
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MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer");
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MODULE_LICENSE("GPL");
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/*
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* initialize an event record
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*/
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static void snd_virmidi_init_event(struct snd_virmidi *vmidi,
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struct snd_seq_event *ev)
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{
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memset(ev, 0, sizeof(*ev));
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ev->source.port = vmidi->port;
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switch (vmidi->seq_mode) {
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case SNDRV_VIRMIDI_SEQ_DISPATCH:
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ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
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break;
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case SNDRV_VIRMIDI_SEQ_ATTACH:
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/* FIXME: source and destination are same - not good.. */
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ev->dest.client = vmidi->client;
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ev->dest.port = vmidi->port;
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break;
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}
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ev->type = SNDRV_SEQ_EVENT_NONE;
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}
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/*
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* decode input event and put to read buffer of each opened file
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*/
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static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,
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struct snd_seq_event *ev)
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{
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struct snd_virmidi *vmidi;
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unsigned char msg[4];
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int len;
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read_lock(&rdev->filelist_lock);
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list_for_each_entry(vmidi, &rdev->filelist, list) {
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if (!vmidi->trigger)
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continue;
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if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
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if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
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continue;
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snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream);
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} else {
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len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev);
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if (len > 0)
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snd_rawmidi_receive(vmidi->substream, msg, len);
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}
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}
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read_unlock(&rdev->filelist_lock);
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return 0;
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}
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/*
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* receive an event from the remote virmidi port
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*
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* for rawmidi inputs, you can call this function from the event
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* handler of a remote port which is attached to the virmidi via
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* SNDRV_VIRMIDI_SEQ_ATTACH.
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*/
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#if 0
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int snd_virmidi_receive(struct snd_rawmidi *rmidi, struct snd_seq_event *ev)
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{
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struct snd_virmidi_dev *rdev;
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rdev = rmidi->private_data;
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return snd_virmidi_dev_receive_event(rdev, ev);
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}
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#endif /* 0 */
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/*
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* event handler of virmidi port
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*/
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static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,
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void *private_data, int atomic, int hop)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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if (!(rdev->flags & SNDRV_VIRMIDI_USE))
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return 0; /* ignored */
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return snd_virmidi_dev_receive_event(rdev, ev);
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}
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/*
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* trigger rawmidi stream for input
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*/
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static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
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{
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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if (up) {
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vmidi->trigger = 1;
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} else {
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vmidi->trigger = 0;
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}
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}
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/*
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* trigger rawmidi stream for output
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*/
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static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
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{
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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int count, res;
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unsigned char buf[32], *pbuf;
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unsigned long flags;
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if (up) {
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vmidi->trigger = 1;
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if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&
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!(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {
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while (snd_rawmidi_transmit(substream, buf,
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sizeof(buf)) > 0) {
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/* ignored */
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}
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return;
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}
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if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
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if (snd_seq_kernel_client_dispatch(vmidi->client, &vmidi->event, in_atomic(), 0) < 0)
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return;
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vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
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}
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spin_lock_irqsave(&substream->runtime->lock, flags);
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while (1) {
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count = __snd_rawmidi_transmit_peek(substream, buf, sizeof(buf));
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if (count <= 0)
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break;
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pbuf = buf;
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while (count > 0) {
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res = snd_midi_event_encode(vmidi->parser, pbuf, count, &vmidi->event);
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if (res < 0) {
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snd_midi_event_reset_encode(vmidi->parser);
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continue;
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}
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__snd_rawmidi_transmit_ack(substream, res);
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pbuf += res;
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count -= res;
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if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
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if (snd_seq_kernel_client_dispatch(vmidi->client, &vmidi->event, in_atomic(), 0) < 0)
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goto out;
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vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
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}
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}
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}
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out:
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spin_unlock_irqrestore(&substream->runtime->lock, flags);
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} else {
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vmidi->trigger = 0;
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}
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}
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/*
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* open rawmidi handle for input
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*/
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static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
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struct snd_rawmidi_runtime *runtime = substream->runtime;
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struct snd_virmidi *vmidi;
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unsigned long flags;
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vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
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if (vmidi == NULL)
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return -ENOMEM;
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vmidi->substream = substream;
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if (snd_midi_event_new(0, &vmidi->parser) < 0) {
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kfree(vmidi);
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return -ENOMEM;
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}
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vmidi->seq_mode = rdev->seq_mode;
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vmidi->client = rdev->client;
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vmidi->port = rdev->port;
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runtime->private_data = vmidi;
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write_lock_irqsave(&rdev->filelist_lock, flags);
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list_add_tail(&vmidi->list, &rdev->filelist);
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write_unlock_irqrestore(&rdev->filelist_lock, flags);
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vmidi->rdev = rdev;
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return 0;
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}
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/*
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* open rawmidi handle for output
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*/
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static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
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struct snd_rawmidi_runtime *runtime = substream->runtime;
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struct snd_virmidi *vmidi;
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vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
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if (vmidi == NULL)
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return -ENOMEM;
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vmidi->substream = substream;
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if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) {
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kfree(vmidi);
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return -ENOMEM;
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}
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vmidi->seq_mode = rdev->seq_mode;
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vmidi->client = rdev->client;
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vmidi->port = rdev->port;
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snd_virmidi_init_event(vmidi, &vmidi->event);
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vmidi->rdev = rdev;
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runtime->private_data = vmidi;
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return 0;
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}
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/*
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* close rawmidi handle for input
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*/
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static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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write_lock_irq(&rdev->filelist_lock);
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list_del(&vmidi->list);
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write_unlock_irq(&rdev->filelist_lock);
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snd_midi_event_free(vmidi->parser);
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substream->runtime->private_data = NULL;
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kfree(vmidi);
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return 0;
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}
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/*
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* close rawmidi handle for output
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*/
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static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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snd_midi_event_free(vmidi->parser);
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substream->runtime->private_data = NULL;
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kfree(vmidi);
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return 0;
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}
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/*
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* subscribe callback - allow output to rawmidi device
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*/
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static int snd_virmidi_subscribe(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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if (!try_module_get(rdev->card->module))
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return -EFAULT;
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rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE;
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return 0;
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}
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/*
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* unsubscribe callback - disallow output to rawmidi device
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*/
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static int snd_virmidi_unsubscribe(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE;
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module_put(rdev->card->module);
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return 0;
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}
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/*
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* use callback - allow input to rawmidi device
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*/
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static int snd_virmidi_use(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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if (!try_module_get(rdev->card->module))
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return -EFAULT;
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rdev->flags |= SNDRV_VIRMIDI_USE;
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return 0;
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}
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/*
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* unuse callback - disallow input to rawmidi device
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*/
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static int snd_virmidi_unuse(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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rdev->flags &= ~SNDRV_VIRMIDI_USE;
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module_put(rdev->card->module);
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return 0;
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}
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/*
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* Register functions
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*/
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static struct snd_rawmidi_ops snd_virmidi_input_ops = {
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.open = snd_virmidi_input_open,
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.close = snd_virmidi_input_close,
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.trigger = snd_virmidi_input_trigger,
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};
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static struct snd_rawmidi_ops snd_virmidi_output_ops = {
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.open = snd_virmidi_output_open,
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.close = snd_virmidi_output_close,
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.trigger = snd_virmidi_output_trigger,
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};
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/*
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* create a sequencer client and a port
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*/
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static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)
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{
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int client;
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struct snd_seq_port_callback pcallbacks;
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struct snd_seq_port_info *pinfo;
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int err;
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if (rdev->client >= 0)
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return 0;
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pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL);
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if (!pinfo) {
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err = -ENOMEM;
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goto __error;
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}
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client = snd_seq_create_kernel_client(rdev->card, rdev->device,
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"%s %d-%d", rdev->rmidi->name,
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rdev->card->number,
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rdev->device);
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if (client < 0) {
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err = client;
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goto __error;
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}
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rdev->client = client;
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/* create a port */
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pinfo->addr.client = client;
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sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device);
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/* set all capabilities */
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pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
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pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
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pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
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pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
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| SNDRV_SEQ_PORT_TYPE_SOFTWARE
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| SNDRV_SEQ_PORT_TYPE_PORT;
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pinfo->midi_channels = 16;
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memset(&pcallbacks, 0, sizeof(pcallbacks));
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pcallbacks.owner = THIS_MODULE;
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pcallbacks.private_data = rdev;
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pcallbacks.subscribe = snd_virmidi_subscribe;
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pcallbacks.unsubscribe = snd_virmidi_unsubscribe;
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pcallbacks.use = snd_virmidi_use;
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pcallbacks.unuse = snd_virmidi_unuse;
|
|
pcallbacks.event_input = snd_virmidi_event_input;
|
|
pinfo->kernel = &pcallbacks;
|
|
err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo);
|
|
if (err < 0) {
|
|
snd_seq_delete_kernel_client(client);
|
|
rdev->client = -1;
|
|
goto __error;
|
|
}
|
|
|
|
rdev->port = pinfo->addr.port;
|
|
err = 0; /* success */
|
|
|
|
__error:
|
|
kfree(pinfo);
|
|
return err;
|
|
}
|
|
|
|
|
|
/*
|
|
* release the sequencer client
|
|
*/
|
|
static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)
|
|
{
|
|
if (rdev->client >= 0) {
|
|
snd_seq_delete_kernel_client(rdev->client);
|
|
rdev->client = -1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* register the device
|
|
*/
|
|
static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)
|
|
{
|
|
struct snd_virmidi_dev *rdev = rmidi->private_data;
|
|
int err;
|
|
|
|
switch (rdev->seq_mode) {
|
|
case SNDRV_VIRMIDI_SEQ_DISPATCH:
|
|
err = snd_virmidi_dev_attach_seq(rdev);
|
|
if (err < 0)
|
|
return err;
|
|
break;
|
|
case SNDRV_VIRMIDI_SEQ_ATTACH:
|
|
if (rdev->client == 0)
|
|
return -EINVAL;
|
|
/* should check presence of port more strictly.. */
|
|
break;
|
|
default:
|
|
pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode);
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* unregister the device
|
|
*/
|
|
static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
|
|
{
|
|
struct snd_virmidi_dev *rdev = rmidi->private_data;
|
|
|
|
if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)
|
|
snd_virmidi_dev_detach_seq(rdev);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
*
|
|
*/
|
|
static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
|
|
.dev_register = snd_virmidi_dev_register,
|
|
.dev_unregister = snd_virmidi_dev_unregister,
|
|
};
|
|
|
|
/*
|
|
* free device
|
|
*/
|
|
static void snd_virmidi_free(struct snd_rawmidi *rmidi)
|
|
{
|
|
struct snd_virmidi_dev *rdev = rmidi->private_data;
|
|
kfree(rdev);
|
|
}
|
|
|
|
/*
|
|
* create a new device
|
|
*
|
|
*/
|
|
/* exported */
|
|
int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)
|
|
{
|
|
struct snd_rawmidi *rmidi;
|
|
struct snd_virmidi_dev *rdev;
|
|
int err;
|
|
|
|
*rrmidi = NULL;
|
|
if ((err = snd_rawmidi_new(card, "VirMidi", device,
|
|
16, /* may be configurable */
|
|
16, /* may be configurable */
|
|
&rmidi)) < 0)
|
|
return err;
|
|
strcpy(rmidi->name, rmidi->id);
|
|
rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
|
|
if (rdev == NULL) {
|
|
snd_device_free(card, rmidi);
|
|
return -ENOMEM;
|
|
}
|
|
rdev->card = card;
|
|
rdev->rmidi = rmidi;
|
|
rdev->device = device;
|
|
rdev->client = -1;
|
|
rwlock_init(&rdev->filelist_lock);
|
|
INIT_LIST_HEAD(&rdev->filelist);
|
|
rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
|
|
rmidi->private_data = rdev;
|
|
rmidi->private_free = snd_virmidi_free;
|
|
rmidi->ops = &snd_virmidi_global_ops;
|
|
snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops);
|
|
snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops);
|
|
rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT |
|
|
SNDRV_RAWMIDI_INFO_OUTPUT |
|
|
SNDRV_RAWMIDI_INFO_DUPLEX;
|
|
*rrmidi = rmidi;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* ENTRY functions
|
|
*/
|
|
|
|
static int __init alsa_virmidi_init(void)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void __exit alsa_virmidi_exit(void)
|
|
{
|
|
}
|
|
|
|
module_init(alsa_virmidi_init)
|
|
module_exit(alsa_virmidi_exit)
|
|
|
|
EXPORT_SYMBOL(snd_virmidi_new);
|