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authorPhillip Potter <phil@philpotter.co.uk>2021-05-03 13:57:18 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-06-03 08:38:09 +0200
commit5bbe8ae1cb97682dc17beeaef637fed6cbc90237 (patch)
tree0550dd5a220d6f52bc1f1699260f627df5a27cd3 /drivers
parent5761baafe988d4d0eaac0e5b0e64949074d9b15d (diff)
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>
Diffstat (limited to 'drivers')
-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 d64edeb6771a..f9640e37b139 100644
--- a/drivers/dma/qcom/hidma_mgmt.c
+++ b/drivers/dma/qcom/hidma_mgmt.c
@@ -423,6 +423,20 @@ 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;