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authorPhillip Potter <phil@philpotter.co.uk>2021-05-03 14:57:18 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-06-03 09:59:10 +0300
commit6c52bc7482e3bd28780257fd5a769754beebc886 (patch)
tree3680a7085cbf4e3e0dbddc4879dc953b51e23620
parente829b7253e4dea76e9eeec2ecfb56cb980803ac6 (diff)
downloadlinux-6c52bc7482e3bd28780257fd5a769754beebc886.tar.xz
dmaengine: qcom_hidma: comment platform_driver_register call
[ Upstream commit 4df2a8b0ad634d98a67e540a4e18a60f943e7d9f ] Place a comment in hidma_mgmt_init explaining why success must currently be assumed, due to the cleanup issue that would need to be considered were this module ever to be unloadable or were this platform_driver_register call ever to fail. Acked-By: Vinod Koul <vkoul@kernel.org> Acked-By: Sinan Kaya <okaya@kernel.org> Signed-off-by: Phillip Potter <phil@philpotter.co.uk> Link: https://lore.kernel.org/r/20210503115736.2104747-52-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/dma/qcom/hidma_mgmt.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/dma/qcom/hidma_mgmt.c b/drivers/dma/qcom/hidma_mgmt.c
index fe87b01f7a4e..62026607f3f8 100644
--- a/drivers/dma/qcom/hidma_mgmt.c
+++ b/drivers/dma/qcom/hidma_mgmt.c
@@ -418,6 +418,20 @@ static int __init hidma_mgmt_init(void)
hidma_mgmt_of_populate_channels(child);
}
#endif
+ /*
+ * We do not check for return value here, as it is assumed that
+ * platform_driver_register must not fail. The reason for this is that
+ * the (potential) hidma_mgmt_of_populate_channels calls above are not
+ * cleaned up if it does fail, and to do this work is quite
+ * complicated. In particular, various calls of of_address_to_resource,
+ * of_irq_to_resource, platform_device_register_full, of_dma_configure,
+ * and of_msi_configure which then call other functions and so on, must
+ * be cleaned up - this is not a trivial exercise.
+ *
+ * Currently, this module is not intended to be unloaded, and there is
+ * no module_exit function defined which does the needed cleanup. For
+ * this reason, we have to assume success here.
+ */
platform_driver_register(&hidma_mgmt_driver);
return 0;