hwrng: Make explicit that max >= 32 always

As hw_random core calls ->read with max > 32 or more, make it explicit.
Also remove checks involving 'max' being less than 8.

Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/msm-rng.c b/drivers/char/hw_random/msm-rng.c
index 96fb986..841fee8 100644 (file)
--- a/drivers/char/hw_random/msm-rng.c
+++ b/drivers/char/hw_random/msm-rng.c
@@ -90,10 +90,6 @@ static int msm_rng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)
        /* calculate max size bytes to transfer back to caller */
        maxsize = min_t(size_t, MAX_HW_FIFO_SIZE, max);
 
-       /* no room for word data */
-       if (maxsize < WORD_SZ)
-               return 0;
-
        ret = clk_prepare_enable(rng->clk);
        if (ret)
                return ret;

diff --git a/drivers/char/hw_random/pic32-rng.c b/drivers/char/hw_random/pic32-rng.c
index 11dc9b7..9b5e68a 100644 (file)
--- a/drivers/char/hw_random/pic32-rng.c
+++ b/drivers/char/hw_random/pic32-rng.c
@@ -62,9 +62,6 @@ static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max,
        u32 t;
        unsigned int timeout = RNG_TIMEOUT;
 
-       if (max < 8)
-               return 0;
-
        do {
                t = readl(priv->base + RNGRCNT) & RCNT_MASK;
                if (t == 64) {

diff --git a/drivers/char/hw_random/pseries-rng.c b/drivers/char/hw_random/pseries-rng.c
index 63ce51d..d9f46b4 100644 (file)
--- a/drivers/char/hw_random/pseries-rng.c
+++ b/drivers/char/hw_random/pseries-rng.c
@@ -28,7 +28,6 @@
 static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 {
        u64 buffer[PLPAR_HCALL_BUFSIZE];
-       size_t size = max < 8 ? max : 8;
        int rc;
 
        rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer);
@@ -36,10 +35,10 @@ static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait
                pr_err_ratelimited("H_RANDOM call failed %d\n", rc);
                return -EIO;
        }
-       memcpy(data, buffer, size);
+       memcpy(data, buffer, 8);
 
        /* The hypervisor interface returns 64 bits */
-       return size;
+       return 8;
 }
 
 /**

diff --git a/include/linux/hw_random.h b/include/linux/hw_random.h
index 34a0dc1..bee0827 100644 (file)
--- a/include/linux/hw_random.h
+++ b/include/linux/hw_random.h
@@ -30,8 +30,7 @@
  *                     Must not be NULL.    *OBSOLETE*
  * @read:              New API. drivers can fill up to max bytes of data
  *                     into the buffer. The buffer is aligned for any type
- *                     and max is guaranteed to be >= to that alignment
- *                     (either 4 or 8 depending on architecture).
+ *                     and max is a multiple of 4 and >= 32 bytes.
  * @priv:              Private data, for use by the RNG driver.
  * @quality:           Estimation of true entropy in RNG's bitstream
  *                     (per mill).