diff options
author | 2017-03-08 23:13:28 -0800 | |
---|---|---|
committer | 2017-03-08 23:36:15 -0800 | |
commit | 52f993b8e89487ec9ee15a7fb4979e0f09a45b27 (patch) | |
tree | d65304486afe0bea4a311c783c0d72791c8c0aa2 /kernel/sound/firewire/fireworks/fireworks_hwdep.c | |
parent | c189ccac5702322ed843fe17057035b7222a59b6 (diff) |
Upgrade to 4.4.50-rt62
The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git
b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e
where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt
c) One patch has been backported thus revert the patch before applying.
filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff |patch -p1 --dry-run
Upstream status: backport
Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Diffstat (limited to 'kernel/sound/firewire/fireworks/fireworks_hwdep.c')
-rw-r--r-- | kernel/sound/firewire/fireworks/fireworks_hwdep.c | 71 |
1 files changed, 52 insertions, 19 deletions
diff --git a/kernel/sound/firewire/fireworks/fireworks_hwdep.c b/kernel/sound/firewire/fireworks/fireworks_hwdep.c index 33df8655f..2e1d9a239 100644 --- a/kernel/sound/firewire/fireworks/fireworks_hwdep.c +++ b/kernel/sound/firewire/fireworks/fireworks_hwdep.c @@ -25,6 +25,7 @@ hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained, { unsigned int length, till_end, type; struct snd_efw_transaction *t; + u8 *pull_ptr; long count = 0; if (remained < sizeof(type) + sizeof(struct snd_efw_transaction)) @@ -38,8 +39,17 @@ hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained, buf += sizeof(type); /* write into buffer as many responses as possible */ - while (efw->resp_queues > 0) { - t = (struct snd_efw_transaction *)(efw->pull_ptr); + spin_lock_irq(&efw->lock); + + /* + * When another task reaches here during this task's access to user + * space, it picks up current position in buffer and can read the same + * series of responses. + */ + pull_ptr = efw->pull_ptr; + + while (efw->push_ptr != pull_ptr) { + t = (struct snd_efw_transaction *)(pull_ptr); length = be32_to_cpu(t->length) * sizeof(__be32); /* confirm enough space for this response */ @@ -49,26 +59,39 @@ hwdep_read_resp_buf(struct snd_efw *efw, char __user *buf, long remained, /* copy from ring buffer to user buffer */ while (length > 0) { till_end = snd_efw_resp_buf_size - - (unsigned int)(efw->pull_ptr - efw->resp_buf); + (unsigned int)(pull_ptr - efw->resp_buf); till_end = min_t(unsigned int, length, till_end); - if (copy_to_user(buf, efw->pull_ptr, till_end)) + spin_unlock_irq(&efw->lock); + + if (copy_to_user(buf, pull_ptr, till_end)) return -EFAULT; - efw->pull_ptr += till_end; - if (efw->pull_ptr >= efw->resp_buf + - snd_efw_resp_buf_size) - efw->pull_ptr -= snd_efw_resp_buf_size; + spin_lock_irq(&efw->lock); + + pull_ptr += till_end; + if (pull_ptr >= efw->resp_buf + snd_efw_resp_buf_size) + pull_ptr -= snd_efw_resp_buf_size; length -= till_end; buf += till_end; count += till_end; remained -= till_end; } - - efw->resp_queues--; } + /* + * All of tasks can read from the buffer nearly simultaneously, but the + * last position for each task is different depending on the length of + * given buffer. Here, for simplicity, a position of buffer is set by + * the latest task. It's better for a listening application to allow one + * thread to read from the buffer. Unless, each task can read different + * sequence of responses depending on variation of buffer length. + */ + efw->pull_ptr = pull_ptr; + + spin_unlock_irq(&efw->lock); + return count; } @@ -76,14 +99,17 @@ static long hwdep_read_locked(struct snd_efw *efw, char __user *buf, long count, loff_t *offset) { - union snd_firewire_event event; + union snd_firewire_event event = { + .lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS, + }; - memset(&event, 0, sizeof(event)); + spin_lock_irq(&efw->lock); - event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS; event.lock_status.status = (efw->dev_lock_count > 0); efw->dev_lock_changed = false; + spin_unlock_irq(&efw->lock); + count = min_t(long, count, sizeof(event.lock_status)); if (copy_to_user(buf, &event, count)) @@ -98,10 +124,15 @@ hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, { struct snd_efw *efw = hwdep->private_data; DEFINE_WAIT(wait); + bool dev_lock_changed; + bool queued; spin_lock_irq(&efw->lock); - while ((!efw->dev_lock_changed) && (efw->resp_queues == 0)) { + dev_lock_changed = efw->dev_lock_changed; + queued = efw->push_ptr != efw->pull_ptr; + + while (!dev_lock_changed && !queued) { prepare_to_wait(&efw->hwdep_wait, &wait, TASK_INTERRUPTIBLE); spin_unlock_irq(&efw->lock); schedule(); @@ -109,15 +140,17 @@ hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count, if (signal_pending(current)) return -ERESTARTSYS; spin_lock_irq(&efw->lock); + dev_lock_changed = efw->dev_lock_changed; + queued = efw->push_ptr != efw->pull_ptr; } - if (efw->dev_lock_changed) + spin_unlock_irq(&efw->lock); + + if (dev_lock_changed) count = hwdep_read_locked(efw, buf, count, offset); - else if (efw->resp_queues > 0) + else if (queued) count = hwdep_read_resp_buf(efw, buf, count, offset); - spin_unlock_irq(&efw->lock); - return count; } @@ -160,7 +193,7 @@ hwdep_poll(struct snd_hwdep *hwdep, struct file *file, poll_table *wait) poll_wait(file, &efw->hwdep_wait, wait); spin_lock_irq(&efw->lock); - if (efw->dev_lock_changed || (efw->resp_queues > 0)) + if (efw->dev_lock_changed || efw->pull_ptr != efw->push_ptr) events = POLLIN | POLLRDNORM; else events = 0; |