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iio: buffer: make sure O_NONBLOCK is respected

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For output buffers, there's no guarantee that the buffer won't be full
in the first iteration of the loop in which case we would block
independently of userspace passing O_NONBLOCK or not. Fix it by always
checking the flag before going to sleep.

While at it (and as it's a bit related), refactored the loop so that the
stop condition is 'written != n', i.e, run the loop until all data has
been copied into the IIO buffers. This makes the code a bit simpler.

Fixes: 9eeee3b0bf ("iio: Add output buffer support")
Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20230216101452.591805-3-nuno.sa@analog.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Nuno Sá 2023-02-16 11:14:51 +01:00 committed by Jonathan Cameron
parent b5184a26a2
commit 3da1814184
1 changed files with 11 additions and 8 deletions
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19
drivers/iio/industrialio-buffer.c
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@ -203,21 +203,24 @@ static ssize_t iio_buffer_write(struct file *filp, const char __user *buf,
break;
}
if (filp->f_flags & O_NONBLOCK) {
if (!written)
ret = -EAGAIN;
break;
}
wait_woken(&wait, TASK_INTERRUPTIBLE,
MAX_SCHEDULE_TIMEOUT);
continue;
}
ret = rb->access->write(rb, n - written, buf + written);
if (ret == 0 && (filp->f_flags & O_NONBLOCK))
ret = -EAGAIN;
if (ret < 0)
break;
if (ret > 0) {
written += ret;
if (written != n && !(filp->f_flags & O_NONBLOCK))
continue;
}
} while (ret == 0);
written += ret;
} while (written != n);
remove_wait_queue(&rb->pollq, &wait);
return ret < 0 ? ret : written;