Messages in this thread | | | Subject | Re: [PATCH] rapidio: use a reference count for struct mport_dma_req | From | Alex Bounine <> | Date | Mon, 9 Apr 2018 15:39:36 -0400 |
| |
On 2018-04-05 04:33 PM, Ioan Nicu wrote: > Once the dma request is passed to the DMA engine, the DMA > subsystem would hold a pointer to this structure and could > call the completion callback after do_dma_request() has > timed out. > > The current code deals with this by putting timed out SYNC > requests to a pending list and freeing them later, when the > mport cdev device is released. But this still does not > guarantee that the DMA subsystem is really done with those > transfers, so in theory dma_xfer_callback/dma_req_free > could be called after mport_cdev_release_dma and could > potentially access already freed memory. > > This patch simplifies the current handling by using a kref > in the mport dma request structure, so that it gets freed > only when nobody uses it anymore. > > This also simplifies the code a bit, as FAF transfers are > now handled in the same way as SYNC and ASYNC transfers. > There is no need anymore for the pending list and for the > dma workqueue which was used in case of FAF transfers, so > we remove them both. > > Signed-off-by: Ioan Nicu <ioan.nicu.ext@nokia.com> > --- > drivers/rapidio/devices/rio_mport_cdev.c | 122 +++++-------------------------- > 1 file changed, 18 insertions(+), 104 deletions(-)
Acked-by: Alexandre Bounine <alex.bou9@gmail.com>
| |