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  1. 18 10月, 2013 4 次提交
  3. 17 10月, 2013 17 次提交
  5. 16 10月, 2013 4 次提交
    • L
      iio:kfifo: Set update_needed to false after allocating a new buffer · cb6fbfa1
      由 Lars-Peter Clausen 提交于 
      update_needed is used to decide whether the kfifo buffer needs to be
re-allocated. It is set to true whenever the size of the buffer is changed. It
is never set to false though, causing the buffer to always be re-allocated.
Setting update_needed to false after the new buffer has been allocated fixes the
problem.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
      cb6fbfa1
    • L
      iio:kfifo: Empty buffer on update · 5b78e513
      由 Lars-Peter Clausen 提交于 
      The kfifo's request_update callback will free the current buffer and allocate a
new one if the size has changed. This will remove any samples that might still
be left in the buffer. If the size has not changed the buffer content is
left untouched though. This is a bit inconsistent and might cause an application
to see data from a previous capture. This patch inserts a call to
kfifo_reset_out() when the size did not change. This makes sure that any pending
samples are removed from the buffer.

Note, due to a different bug the buffer is currently always re-allocated, even
if the size did not change. So this patch will not change the behavior. In the
next patch the bug will be fixed and this patch makes sure that the current
behavior is kept.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
      5b78e513
    • L
      iio:kfifo: Protect against concurrent access from userspace · 0894d80d
      由 Lars-Peter Clausen 提交于 
      It is possible for userspace to concurrently access the buffer from multiple
threads or processes. To avoid corruption of the internal state of the buffer we
need to add proper locking. It is possible for multiple processes to try to read
from the buffer concurrently and it is also possible that one process causes a
buffer re-allocation while a different process still access the buffer. Both can
be fixed by protecting the calls to kfifo_to_user() and kfifo_alloc() by the
same mutex. In iio_read_first_n_kfifo() we also use kfifo_recsize() instead of
the buffers bytes_per_datum to avoid a race that can happen if bytes_per_datum
has been changed, but the buffer has not been reallocated yet.

Note that all access to the buffer from within the kernel is already properly
synchronized, so there is no need for extra locking in iio_store_to_kfifo().
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
      0894d80d
    • L
      iio:kfifo: Fix memory leak · f6c23f48
      由 Lars-Peter Clausen 提交于 
      We need to free the kfifo when we release the buffer, otherwise the fifos memory
will be leaked.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
      f6c23f48
  7. 15 10月, 2013 3 次提交
  9. 12 10月, 2013 12 次提交