6.6-stable review patch. If anyone has any objections, please let me know.
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From: Francesco Dolcini francesco.dolcini@toradex.com
commit c8820c92caf0770bec976b01fa9e82bb993c5865 upstream.
Serdev recv_buf() callback is supposed to return the amount of bytes consumed, therefore an int in between 0 and count.
Do not return negative number in case of issue, when ssam_controller_receive_buf() returns ESHUTDOWN just returns 0, e.g. no bytes consumed, this keep the exact same behavior as it was before.
This fixes a potential WARN in serdev-ttyport.c:ttyport_receive_buf().
Fixes: c167b9c7e3d6 ("platform/surface: Add Surface Aggregator subsystem") Cc: stable@vger.kernel.org Signed-off-by: Francesco Dolcini francesco.dolcini@toradex.com Reviewed-by: Maximilian Luz luzmaximilian@gmail.com Link: https://lore.kernel.org/r/20231128194935.11350-1-francesco@dolcini.it Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/platform/surface/aggregator/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/platform/surface/aggregator/core.c +++ b/drivers/platform/surface/aggregator/core.c @@ -231,9 +231,12 @@ static int ssam_receive_buf(struct serde size_t n) { struct ssam_controller *ctrl; + int ret;
ctrl = serdev_device_get_drvdata(dev); - return ssam_controller_receive_buf(ctrl, buf, n); + ret = ssam_controller_receive_buf(ctrl, buf, n); + + return ret < 0 ? 0 : ret; }
static void ssam_write_wakeup(struct serdev_device *dev)