[S390] hw_random: allow rng_dev_read() to return hardware errors.
The api for hardware random number generators is currently limited to
devices that never fail. If the hardware is registered as a source for
random numbers it has to work. This prevents the use of i/o based
random number devices where the i/o might fail.
Add a check for errors after the read from a hardware random number device.
This patch is required to support large random numbers retrieved
from the CEX2C cards on System z.
Signed-off-by: Ralph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 84cdf90..349b6ed 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -116,6 +116,10 @@
err = -EAGAIN;
if (!bytes_read && (filp->f_flags & O_NONBLOCK))
goto out;
+ if (bytes_read < 0) {
+ err = bytes_read;
+ goto out;
+ }
err = -EFAULT;
while (bytes_read && size) {