The current code waits for data to be available before attempting a
second read. However the second read would not be executed as the
while loop exits.
This fix does not wait if all data has been read and reads a second
time if only partial data was retrieved on the first read.
This fix also does not attempt to read if not data is requested.
Signed-off-by: Jorge Ramirez-Ortiz <jorge@xxxxxxxxxxxx>
---
v2: tidy up the while loop to avoid reading when no data is requested
drivers/char/hw_random/optee-rng.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/hw_random/optee-rng.c b/drivers/char/hw_random/optee-rng.c
index 5bc4700c4dae..a99d82949981 100644
--- a/drivers/char/hw_random/optee-rng.c
+++ b/drivers/char/hw_random/optee-rng.c
@@ -122,14 +122,14 @@ static int optee_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
if (max > MAX_ENTROPY_REQ_SZ)
max = MAX_ENTROPY_REQ_SZ;
- while (read == 0) {
+ while (read < max) {
rng_size = get_optee_rng_data(pvt_data, data, (max - read));
data += rng_size;
read += rng_size;
if (wait && pvt_data->data_rate) {
- if (timeout-- == 0)
+ if ((timeout-- == 0) || (read == max))
return read;
msleep((1000 * (max - read)) / pvt_data->data_rate);
} else {
--
2.17.1
