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pcm: another weird API abuse

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readv() and writev() should _not_ ignore all but the first ->iov_len,
among other things.  Really weird abuse of those syscalls - it
expects a vector element per channel, with identical lengths (it
actually assumes them to be identical - no checking is done).
readv() and writev() are really bad match for that.  Unfortunately,
userland API is userland API and we can't do anything about them.

Converted to ->read_iter/->write_iter.  Please, _please_ don't do
anything of that kind when designing new interfaces.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-04-04 00:19:32 -04:00
commit 1c65d98672
1 changed files with 20 additions and 19 deletions
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39
sound/core/pcm_native.c
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@ -3033,9 +3033,7 @@ static ssize_t snd_pcm_write(struct file *file, const char __user *buf,
return result; return result;
} }
static ssize_t snd_pcm_aio_read(struct kiocb *iocb, const struct iovec *iov, static ssize_t snd_pcm_readv(struct kiocb *iocb, struct iov_iter *to)
unsigned long nr_segs, loff_t pos)
{ {
struct snd_pcm_file *pcm_file; struct snd_pcm_file *pcm_file;
struct snd_pcm_substream *substream; struct snd_pcm_substream *substream;
@ -3052,16 +3050,18 @@ static ssize_t snd_pcm_aio_read(struct kiocb *iocb, const struct iovec *iov,
runtime = substream->runtime; runtime = substream->runtime;
if (runtime->status->state == SNDRV_PCM_STATE_OPEN) if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
return -EBADFD; return -EBADFD;
if (nr_segs > 1024 || nr_segs != runtime->channels) if (!iter_is_iovec(to))
return -EINVAL; return -EINVAL;
if (!frame_aligned(runtime, iov->iov_len)) if (to->nr_segs > 1024 || to->nr_segs != runtime->channels)
return -EINVAL; return -EINVAL;
frames = bytes_to_samples(runtime, iov->iov_len); if (!frame_aligned(runtime, to->iov->iov_len))
bufs = kmalloc(sizeof(void *) * nr_segs, GFP_KERNEL); return -EINVAL;
frames = bytes_to_samples(runtime, to->iov->iov_len);
bufs = kmalloc(sizeof(void *) * to->nr_segs, GFP_KERNEL);
if (bufs == NULL) if (bufs == NULL)
return -ENOMEM; return -ENOMEM;
for (i = 0; i < nr_segs; ++i) for (i = 0; i < to->nr_segs; ++i)
bufs[i] = iov[i].iov_base; bufs[i] = to->iov[i].iov_base;
result = snd_pcm_lib_readv(substream, bufs, frames); result = snd_pcm_lib_readv(substream, bufs, frames);
if (result > 0) if (result > 0)
result = frames_to_bytes(runtime, result); result = frames_to_bytes(runtime, result);
@ -3069,8 +3069,7 @@ static ssize_t snd_pcm_aio_read(struct kiocb *iocb, const struct iovec *iov,
return result; return result;
} }
static ssize_t snd_pcm_aio_write(struct kiocb *iocb, const struct iovec *iov, static ssize_t snd_pcm_writev(struct kiocb *iocb, struct iov_iter *from)
unsigned long nr_segs, loff_t pos)
{ {
struct snd_pcm_file *pcm_file; struct snd_pcm_file *pcm_file;
struct snd_pcm_substream *substream; struct snd_pcm_substream *substream;
@ -3087,15 +3086,17 @@ static ssize_t snd_pcm_aio_write(struct kiocb *iocb, const struct iovec *iov,
runtime = substream->runtime; runtime = substream->runtime;
if (runtime->status->state == SNDRV_PCM_STATE_OPEN) if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
return -EBADFD; return -EBADFD;
if (nr_segs > 128 || nr_segs != runtime->channels || if (!iter_is_iovec(from))
!frame_aligned(runtime, iov->iov_len))
return -EINVAL; return -EINVAL;
frames = bytes_to_samples(runtime, iov->iov_len); if (from->nr_segs > 128 || from->nr_segs != runtime->channels ||
bufs = kmalloc(sizeof(void *) * nr_segs, GFP_KERNEL); !frame_aligned(runtime, from->iov->iov_len))
return -EINVAL;
frames = bytes_to_samples(runtime, from->iov->iov_len);
bufs = kmalloc(sizeof(void *) * from->nr_segs, GFP_KERNEL);
if (bufs == NULL) if (bufs == NULL)
return -ENOMEM; return -ENOMEM;
for (i = 0; i < nr_segs; ++i) for (i = 0; i < from->nr_segs; ++i)
bufs[i] = iov[i].iov_base; bufs[i] = from->iov[i].iov_base;
result = snd_pcm_lib_writev(substream, bufs, frames); result = snd_pcm_lib_writev(substream, bufs, frames);
if (result > 0) if (result > 0)
result = frames_to_bytes(runtime, result); result = frames_to_bytes(runtime, result);
@ -3633,7 +3634,7 @@ const struct file_operations snd_pcm_f_ops[2] = {
{ {
.owner = THIS_MODULE, .owner = THIS_MODULE,
.write = snd_pcm_write, .write = snd_pcm_write,
.aio_write = snd_pcm_aio_write, .write_iter = snd_pcm_writev,
.open = snd_pcm_playback_open, .open = snd_pcm_playback_open,
.release = snd_pcm_release, .release = snd_pcm_release,
.llseek = no_llseek, .llseek = no_llseek,
@ -3647,7 +3648,7 @@ const struct file_operations snd_pcm_f_ops[2] = {
{ {
.owner = THIS_MODULE, .owner = THIS_MODULE,
.read = snd_pcm_read, .read = snd_pcm_read,
.aio_read = snd_pcm_aio_read, .read_iter = snd_pcm_readv,
.open = snd_pcm_capture_open, .open = snd_pcm_capture_open,
.release = snd_pcm_release, .release = snd_pcm_release,
.llseek = no_llseek, .llseek = no_llseek,