From: Vladis Dronov <vdronov@redhat.com>
Date: Wed, 13 Apr 2022 16:16:05 +0200
Subject: hwrng: cn10k - Optimize cn10k_rng_read()
Git-commit: 753d6770879894de10d74b437ab99ea380f1cad7
Patch-mainline: v5.19-rc1
References: jsc#PED-1765
This function assumes that sizeof(void) is 1 and arithmetic works for
void pointers. This is a GNU C extention and may not work with other
compilers. Change this by using an u8 pointer.
Also move cn10k_read_trng() out of a loop thus saving some cycles.
Fixes: 38e9791a0209 ("hwrng: cn10k - Add random number generator support")
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ivan T. Ivanov <iivanov@suse.de>
---
drivers/char/hw_random/cn10k-rng.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/char/hw_random/cn10k-rng.c
+++ b/drivers/char/hw_random/cn10k-rng.c
@@ -90,6 +90,7 @@ static int cn10k_rng_read(struct hwrng *
{
struct cn10k_rng *rng = (struct cn10k_rng *)hwrng->priv;
unsigned int size;
+ u8 *pos = data;
int err = 0;
u64 value;
@@ -102,17 +103,20 @@ static int cn10k_rng_read(struct hwrng *
while (size >= 8) {
cn10k_read_trng(rng, &value);
- *((u64 *)data) = (u64)value;
+ *((u64 *)pos) = value;
size -= 8;
- data += 8;
+ pos += 8;
}
- while (size > 0) {
+ if (size > 0) {
cn10k_read_trng(rng, &value);
- *((u8 *)data) = (u8)value;
- size--;
- data++;
+ while (size > 0) {
+ *pos = (u8)value;
+ value >>= 8;
+ size--;
+ pos++;
+ }
}
return max - size;