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authorTakashi Iwai <tiwai@suse.de>2017-07-06 12:34:40 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-13 14:09:46 -0700
commit55681470154567b4a8a30ec8b35a8ebd5a4f3608 (patch)
treeb6c5cd72f83d031a51e7c901811c4416d04083ed
parent10863607c242e970cfc14c42b35689737c397fe4 (diff)
downloadlinux-linaro-stable-55681470154567b4a8a30ec8b35a8ebd5a4f3608.tar.gz
ALSA: msnd: Optimize / harden DSP and MIDI loops
commit 20e2b791796bd68816fa115f12be5320de2b8021 upstream. The ISA msnd drivers have loops fetching the ring-buffer head, tail and size values inside the loops. Such codes are inefficient and fragile. This patch optimizes it, and also adds the sanity check to avoid the endless loops. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196131 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196133 Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: grygorii tertychnyi <gtertych@cisco.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--sound/isa/msnd/msnd_midi.c30
-rw-r--r--sound/isa/msnd/msnd_pinnacle.c23
2 files changed, 27 insertions, 26 deletions
diff --git a/sound/isa/msnd/msnd_midi.c b/sound/isa/msnd/msnd_midi.c
index ffc67fd..58e59cd 100644
--- a/sound/isa/msnd/msnd_midi.c
+++ b/sound/isa/msnd/msnd_midi.c
@@ -120,24 +120,24 @@ void snd_msndmidi_input_read(void *mpuv)
unsigned long flags;
struct snd_msndmidi *mpu = mpuv;
void *pwMIDQData = mpu->dev->mappedbase + MIDQ_DATA_BUFF;
+ u16 head, tail, size;
spin_lock_irqsave(&mpu->input_lock, flags);
- while (readw(mpu->dev->MIDQ + JQS_wTail) !=
- readw(mpu->dev->MIDQ + JQS_wHead)) {
- u16 wTmp, val;
- val = readw(pwMIDQData + 2 * readw(mpu->dev->MIDQ + JQS_wHead));
-
- if (test_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER,
- &mpu->mode))
- snd_rawmidi_receive(mpu->substream_input,
- (unsigned char *)&val, 1);
-
- wTmp = readw(mpu->dev->MIDQ + JQS_wHead) + 1;
- if (wTmp > readw(mpu->dev->MIDQ + JQS_wSize))
- writew(0, mpu->dev->MIDQ + JQS_wHead);
- else
- writew(wTmp, mpu->dev->MIDQ + JQS_wHead);
+ head = readw(mpu->dev->MIDQ + JQS_wHead);
+ tail = readw(mpu->dev->MIDQ + JQS_wTail);
+ size = readw(mpu->dev->MIDQ + JQS_wSize);
+ if (head > size || tail > size)
+ goto out;
+ while (head != tail) {
+ unsigned char val = readw(pwMIDQData + 2 * head);
+
+ if (test_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER, &mpu->mode))
+ snd_rawmidi_receive(mpu->substream_input, &val, 1);
+ if (++head > size)
+ head = 0;
+ writew(head, mpu->dev->MIDQ + JQS_wHead);
}
+ out:
spin_unlock_irqrestore(&mpu->input_lock, flags);
}
EXPORT_SYMBOL(snd_msndmidi_input_read);
diff --git a/sound/isa/msnd/msnd_pinnacle.c b/sound/isa/msnd/msnd_pinnacle.c
index 4c07266..a31ea6c 100644
--- a/sound/isa/msnd/msnd_pinnacle.c
+++ b/sound/isa/msnd/msnd_pinnacle.c
@@ -170,23 +170,24 @@ static irqreturn_t snd_msnd_interrupt(int irq, void *dev_id)
{
struct snd_msnd *chip = dev_id;
void *pwDSPQData = chip->mappedbase + DSPQ_DATA_BUFF;
+ u16 head, tail, size;
/* Send ack to DSP */
/* inb(chip->io + HP_RXL); */
/* Evaluate queued DSP messages */
- while (readw(chip->DSPQ + JQS_wTail) != readw(chip->DSPQ + JQS_wHead)) {
- u16 wTmp;
-
- snd_msnd_eval_dsp_msg(chip,
- readw(pwDSPQData + 2 * readw(chip->DSPQ + JQS_wHead)));
-
- wTmp = readw(chip->DSPQ + JQS_wHead) + 1;
- if (wTmp > readw(chip->DSPQ + JQS_wSize))
- writew(0, chip->DSPQ + JQS_wHead);
- else
- writew(wTmp, chip->DSPQ + JQS_wHead);
+ head = readw(chip->DSPQ + JQS_wHead);
+ tail = readw(chip->DSPQ + JQS_wTail);
+ size = readw(chip->DSPQ + JQS_wSize);
+ if (head > size || tail > size)
+ goto out;
+ while (head != tail) {
+ snd_msnd_eval_dsp_msg(chip, readw(pwDSPQData + 2 * head));
+ if (++head > size)
+ head = 0;
+ writew(head, chip->DSPQ + JQS_wHead);
}
+ out:
/* Send ack to DSP */
inb(chip->io + HP_RXL);
return IRQ_HANDLED;