[HWRNG]: move status polling loop to data_present callbacks

Handle waiting for new random within the drivers themselves, this allows to
use better suited timeouts for the individual rngs.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 6 insertions, 18 deletions

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 26a860adcb38..0118b9817a95 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -66,11 +66,11 @@ static inline void hwrng_cleanup(struct hwrng *rng)
                 rng->cleanup(rng);
 }
 
-static inline int hwrng_data_present(struct hwrng *rng)
+static inline int hwrng_data_present(struct hwrng *rng, int wait)
 {
         if (!rng->data_present)
                 return 1;
-        return rng->data_present(rng);
+        return rng->data_present(rng, wait);
 }
 
 static inline int hwrng_data_read(struct hwrng *rng, u32 *data)
@@ -94,8 +94,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
 {
         u32 data;
         ssize_t ret = 0;
-        int i, err = 0;
-        int data_present;
+        int err = 0;
         int bytes_read;
 
         while (size) {
@@ -107,21 +106,10 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
                         err = -ENODEV;
                         goto out;
                 }
-                if (filp->f_flags & O_NONBLOCK) {
-                        data_present = hwrng_data_present(current_rng);
-                } else {
-                        /* Some RNG require some time between data_reads to gather
-                         * new entropy. Poll it.
-                         */
-                        for (i = 0; i < 20; i++) {
-                                data_present = hwrng_data_present(current_rng);
-                                if (data_present)
-                                        break;
-                                udelay(10);
-                        }
-                }
+
                 bytes_read = 0;
-                if (data_present)
+                if (hwrng_data_present(current_rng,
+                                       !(filp->f_flags & O_NONBLOCK)))
                         bytes_read = hwrng_data_read(current_rng, &data);
                 mutex_unlock(&rng_mutex);