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ALSA: rawmidi: Move lock to snd_rawmidi_substream

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Having a lock in snd_rawmidi_runtime can be a problem especially when
a substream is accessed from the outside, as the runtime creation
might be racy with the external calls.  As a first step for hardening,
move the spinlock from snd_rawmidi_runtime to snd_rawmidi_substream.

This patch just replaces the lock calls, no real functional change is
put yet.

Link: https://lore.kernel.org/r/20220617144051.18985-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2022-06-17 16:40:48 +02:00
parent cd76175a2b
commit f1d4043335
2 changed files with 65 additions and 68 deletions
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2
include/sound/rawmidi.h
View File

@ -63,7 +63,6 @@ struct snd_rawmidi_runtime {
size_t xruns; /* over/underruns counter */
int buffer_ref; /* buffer reference count */
/* misc */
spinlock_t lock;
wait_queue_head_t sleep;
/* event handler (new bytes, input only) */
void (*event)(struct snd_rawmidi_substream *substream);
@ -85,6 +84,7 @@ struct snd_rawmidi_substream {
unsigned int clock_type; /* clock source to use for input framing */
int use_count; /* use counter (for output) */
size_t bytes;
spinlock_t lock;
struct snd_rawmidi *rmidi;
struct snd_rawmidi_str *pstr;
char name[32];

131
sound/core/rawmidi.c
View File

@ -102,13 +102,12 @@ static inline bool __snd_rawmidi_ready(struct snd_rawmidi_runtime *runtime)
static bool snd_rawmidi_ready(struct snd_rawmidi_substream *substream)
{
struct snd_rawmidi_runtime *runtime = substream->runtime;
unsigned long flags;
bool ready;
spin_lock_irqsave(&runtime->lock, flags);
ready = __snd_rawmidi_ready(runtime);
spin_unlock_irqrestore(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
ready = __snd_rawmidi_ready(substream->runtime);
spin_unlock_irqrestore(&substream->lock, flags);
return ready;
}
@ -130,7 +129,7 @@ static void snd_rawmidi_input_event_work(struct work_struct *work)
runtime->event(runtime->substream);
}
/* buffer refcount management: call with runtime->lock held */
/* buffer refcount management: call with substream->lock held */
static inline void snd_rawmidi_buffer_ref(struct snd_rawmidi_runtime *runtime)
{
runtime->buffer_ref++;
@ -149,7 +148,6 @@ static int snd_rawmidi_runtime_create(struct snd_rawmidi_substream *substream)
if (!runtime)
return -ENOMEM;
runtime->substream = substream;
spin_lock_init(&runtime->lock);
init_waitqueue_head(&runtime->sleep);
INIT_WORK(&runtime->event_work, snd_rawmidi_input_event_work);
runtime->event = NULL;
@ -203,20 +201,20 @@ static void __reset_runtime_ptrs(struct snd_rawmidi_runtime *runtime,
runtime->avail = is_input ? 0 : runtime->buffer_size;
}
static void reset_runtime_ptrs(struct snd_rawmidi_runtime *runtime,
static void reset_runtime_ptrs(struct snd_rawmidi_substream *substream,
bool is_input)
{
unsigned long flags;
spin_lock_irqsave(&runtime->lock, flags);
__reset_runtime_ptrs(runtime, is_input);
spin_unlock_irqrestore(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
__reset_runtime_ptrs(substream->runtime, is_input);
spin_unlock_irqrestore(&substream->lock, flags);
}
int snd_rawmidi_drop_output(struct snd_rawmidi_substream *substream)
{
snd_rawmidi_output_trigger(substream, 0);
reset_runtime_ptrs(substream->runtime, false);
reset_runtime_ptrs(substream, false);
return 0;
}
EXPORT_SYMBOL(snd_rawmidi_drop_output);
@ -256,7 +254,7 @@ EXPORT_SYMBOL(snd_rawmidi_drain_output);
int snd_rawmidi_drain_input(struct snd_rawmidi_substream *substream)
{
snd_rawmidi_input_trigger(substream, 0);
reset_runtime_ptrs(substream->runtime, true);
reset_runtime_ptrs(substream, true);
return 0;
}
EXPORT_SYMBOL(snd_rawmidi_drain_input);
@ -676,10 +674,11 @@ static int snd_rawmidi_info_select_user(struct snd_card *card,
return 0;
}
static int resize_runtime_buffer(struct snd_rawmidi_runtime *runtime,
static int resize_runtime_buffer(struct snd_rawmidi_substream *substream,
struct snd_rawmidi_params *params,
bool is_input)
{
struct snd_rawmidi_runtime *runtime = substream->runtime;
char *newbuf, *oldbuf;
unsigned int framing = params->mode & SNDRV_RAWMIDI_MODE_FRAMING_MASK;
@ -693,9 +692,9 @@ static int resize_runtime_buffer(struct snd_rawmidi_runtime *runtime,
newbuf = kvzalloc(params->buffer_size, GFP_KERNEL);
if (!newbuf)
return -ENOMEM;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
if (runtime->buffer_ref) {
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
kvfree(newbuf);
return -EBUSY;
}
@ -703,7 +702,7 @@ static int resize_runtime_buffer(struct snd_rawmidi_runtime *runtime,
runtime->buffer = newbuf;
runtime->buffer_size = params->buffer_size;
__reset_runtime_ptrs(runtime, is_input);
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
kvfree(oldbuf);
}
runtime->avail_min = params->avail_min;
@ -717,7 +716,7 @@ int snd_rawmidi_output_params(struct snd_rawmidi_substream *substream,
return -EBUSY;
snd_rawmidi_drain_output(substream);
substream->active_sensing = !params->no_active_sensing;
return resize_runtime_buffer(substream->runtime, params, false);
return resize_runtime_buffer(substream, params, false);
}
EXPORT_SYMBOL(snd_rawmidi_output_params);
@ -735,7 +734,7 @@ int snd_rawmidi_input_params(struct snd_rawmidi_substream *substream,
if (framing > SNDRV_RAWMIDI_MODE_FRAMING_TSTAMP)
return -EINVAL;
snd_rawmidi_drain_input(substream);
err = resize_runtime_buffer(substream->runtime, params, true);
err = resize_runtime_buffer(substream, params, true);
if (err < 0)
return err;
@ -752,9 +751,9 @@ static int snd_rawmidi_output_status(struct snd_rawmidi_substream *substream,
memset(status, 0, sizeof(*status));
status->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
status->avail = runtime->avail;
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
return 0;
}
@ -765,11 +764,11 @@ static int snd_rawmidi_input_status(struct snd_rawmidi_substream *substream,
memset(status, 0, sizeof(*status));
status->stream = SNDRV_RAWMIDI_STREAM_INPUT;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
status->avail = runtime->avail;
status->xruns = runtime->xruns;
runtime->xruns = 0;
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
return 0;
}
@ -1074,7 +1073,7 @@ int snd_rawmidi_receive(struct snd_rawmidi_substream *substream,
return -EINVAL;
}
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
if (substream->framing == SNDRV_RAWMIDI_MODE_FRAMING_TSTAMP) {
result = receive_with_tstamp_framing(substream, buffer, count, &ts64);
} else if (count == 1) { /* special case, faster code */
@ -1121,7 +1120,7 @@ int snd_rawmidi_receive(struct snd_rawmidi_substream *substream,
else if (__snd_rawmidi_ready(runtime))
wake_up(&runtime->sleep);
}
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return result;
}
EXPORT_SYMBOL(snd_rawmidi_receive);
@ -1136,7 +1135,7 @@ static long snd_rawmidi_kernel_read1(struct snd_rawmidi_substream *substream,
unsigned long appl_ptr;
int err = 0;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
snd_rawmidi_buffer_ref(runtime);
while (count > 0 && runtime->avail) {
count1 = runtime->buffer_size - runtime->appl_ptr;
@ -1154,11 +1153,11 @@ static long snd_rawmidi_kernel_read1(struct snd_rawmidi_substream *substream,
if (kernelbuf)
memcpy(kernelbuf + result, runtime->buffer + appl_ptr, count1);
if (userbuf) {
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
if (copy_to_user(userbuf + result,
runtime->buffer + appl_ptr, count1))
err = -EFAULT;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
if (err)
goto out;
}
@ -1167,7 +1166,7 @@ static long snd_rawmidi_kernel_read1(struct snd_rawmidi_substream *substream,
}
out:
snd_rawmidi_buffer_unref(runtime);
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return result > 0 ? result : err;
}
@ -1196,31 +1195,31 @@ static ssize_t snd_rawmidi_read(struct file *file, char __user *buf, size_t coun
snd_rawmidi_input_trigger(substream, 1);
result = 0;
while (count > 0) {
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
while (!__snd_rawmidi_ready(runtime)) {
wait_queue_entry_t wait;
if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
return result > 0 ? result : -EAGAIN;
}
init_waitqueue_entry(&wait, current);
add_wait_queue(&runtime->sleep, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
schedule();
remove_wait_queue(&runtime->sleep, &wait);
if (rfile->rmidi->card->shutdown)
return -ENODEV;
if (signal_pending(current))
return result > 0 ? result : -ERESTARTSYS;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
if (!runtime->avail) {
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
return result > 0 ? result : -EIO;
}
}
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
count1 = snd_rawmidi_kernel_read1(substream,
(unsigned char __user *)buf,
NULL/*kernelbuf*/,
@ -1251,9 +1250,9 @@ int snd_rawmidi_transmit_empty(struct snd_rawmidi_substream *substream)
"snd_rawmidi_transmit_empty: output is not active!!!\n");
return 1;
}
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
result = runtime->avail >= runtime->buffer_size;
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return result;
}
EXPORT_SYMBOL(snd_rawmidi_transmit_empty);
@ -1322,13 +1321,12 @@ static int __snd_rawmidi_transmit_peek(struct snd_rawmidi_substream *substream,
int snd_rawmidi_transmit_peek(struct snd_rawmidi_substream *substream,
unsigned char *buffer, int count)
{
struct snd_rawmidi_runtime *runtime = substream->runtime;
int result;
unsigned long flags;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
result = __snd_rawmidi_transmit_peek(substream, buffer, count);
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return result;
}
EXPORT_SYMBOL(snd_rawmidi_transmit_peek);
@ -1375,13 +1373,12 @@ static int __snd_rawmidi_transmit_ack(struct snd_rawmidi_substream *substream,
*/
int snd_rawmidi_transmit_ack(struct snd_rawmidi_substream *substream, int count)
{
struct snd_rawmidi_runtime *runtime = substream->runtime;
int result;
unsigned long flags;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
result = __snd_rawmidi_transmit_ack(substream, count);
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return result;
}
EXPORT_SYMBOL(snd_rawmidi_transmit_ack);
@ -1399,11 +1396,10 @@ EXPORT_SYMBOL(snd_rawmidi_transmit_ack);
int snd_rawmidi_transmit(struct snd_rawmidi_substream *substream,
unsigned char *buffer, int count)
{
struct snd_rawmidi_runtime *runtime = substream->runtime;
int result;
unsigned long flags;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
if (!substream->opened)
result = -EBADFD;
else {
@ -1413,7 +1409,7 @@ int snd_rawmidi_transmit(struct snd_rawmidi_substream *substream,
else
result = __snd_rawmidi_transmit_ack(substream, count);
}
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return result;
}
EXPORT_SYMBOL(snd_rawmidi_transmit);
@ -1430,12 +1426,12 @@ int snd_rawmidi_proceed(struct snd_rawmidi_substream *substream)
unsigned long flags;
int count = 0;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
if (runtime->avail < runtime->buffer_size) {
count = runtime->buffer_size - runtime->avail;
__snd_rawmidi_transmit_ack(substream, count);
}
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return count;
}
EXPORT_SYMBOL(snd_rawmidi_proceed);
@ -1456,10 +1452,10 @@ static long snd_rawmidi_kernel_write1(struct snd_rawmidi_substream *substream,
return -EINVAL;
result = 0;
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
if (substream->append) {
if ((long)runtime->avail < count) {
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
return -EAGAIN;
}
}
@ -1481,14 +1477,14 @@ static long snd_rawmidi_kernel_write1(struct snd_rawmidi_substream *substream,
memcpy(runtime->buffer + appl_ptr,
kernelbuf + result, count1);
else if (userbuf) {
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
if (copy_from_user(runtime->buffer + appl_ptr,
userbuf + result, count1)) {
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
result = result > 0 ? result : -EFAULT;
goto __end;
}
spin_lock_irqsave(&runtime->lock, flags);
spin_lock_irqsave(&substream->lock, flags);
}
result += count1;
count -= count1;
@ -1496,7 +1492,7 @@ static long snd_rawmidi_kernel_write1(struct snd_rawmidi_substream *substream,
__end:
count1 = runtime->avail < runtime->buffer_size;
snd_rawmidi_buffer_unref(runtime);
spin_unlock_irqrestore(&runtime->lock, flags);
spin_unlock_irqrestore(&substream->lock, flags);
if (count1)
snd_rawmidi_output_trigger(substream, 1);
return result;
@ -1526,31 +1522,31 @@ static ssize_t snd_rawmidi_write(struct file *file, const char __user *buf,
return -EIO;
result = 0;
while (count > 0) {
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
while (!snd_rawmidi_ready_append(substream, count)) {
wait_queue_entry_t wait;
if (file->f_flags & O_NONBLOCK) {
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
return result > 0 ? result : -EAGAIN;
}
init_waitqueue_entry(&wait, current);
add_wait_queue(&runtime->sleep, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
timeout = schedule_timeout(30 * HZ);
remove_wait_queue(&runtime->sleep, &wait);
if (rfile->rmidi->card->shutdown)
return -ENODEV;
if (signal_pending(current))
return result > 0 ? result : -ERESTARTSYS;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
if (!runtime->avail && !timeout) {
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
return result > 0 ? result : -EIO;
}
}
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
count1 = snd_rawmidi_kernel_write1(substream, buf, NULL, count);
if (count1 < 0)
return result > 0 ? result : count1;
@ -1561,7 +1557,7 @@ static ssize_t snd_rawmidi_write(struct file *file, const char __user *buf,
count -= count1;
}
if (file->f_flags & O_DSYNC) {
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
while (runtime->avail != runtime->buffer_size) {
wait_queue_entry_t wait;
unsigned int last_avail = runtime->avail;
@ -1569,16 +1565,16 @@ static ssize_t snd_rawmidi_write(struct file *file, const char __user *buf,
init_waitqueue_entry(&wait, current);
add_wait_queue(&runtime->sleep, &wait);
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
timeout = schedule_timeout(30 * HZ);
remove_wait_queue(&runtime->sleep, &wait);
if (signal_pending(current))
return result > 0 ? result : -ERESTARTSYS;
if (runtime->avail == last_avail && !timeout)
return result > 0 ? result : -EIO;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
}
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
}
return result;
}
@ -1649,10 +1645,10 @@ static void snd_rawmidi_proc_info_read(struct snd_info_entry *entry,
" Owner PID : %d\n",
pid_vnr(substream->pid));
runtime = substream->runtime;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
buffer_size = runtime->buffer_size;
avail = runtime->avail;
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
snd_iprintf(buffer,
" Mode : %s\n"
" Buffer size : %lu\n"
@ -1676,11 +1672,11 @@ static void snd_rawmidi_proc_info_read(struct snd_info_entry *entry,
" Owner PID : %d\n",
pid_vnr(substream->pid));
runtime = substream->runtime;
spin_lock_irq(&runtime->lock);
spin_lock_irq(&substream->lock);
buffer_size = runtime->buffer_size;
avail = runtime->avail;
xruns = runtime->xruns;
spin_unlock_irq(&runtime->lock);
spin_unlock_irq(&substream->lock);
snd_iprintf(buffer,
" Buffer size : %lu\n"
" Avail : %lu\n"
@ -1732,6 +1728,7 @@ static int snd_rawmidi_alloc_substreams(struct snd_rawmidi *rmidi,
substream->number = idx;
substream->rmidi = rmidi;
substream->pstr = stream;
spin_lock_init(&substream->lock);
list_add_tail(&substream->list, &stream->substreams);
stream->substream_count++;
}