This is a note to let you know that I've just added the patch titled hwrng: cn10k - Optimize cn10k_rng_read() to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hwrng-cn10k-optimize-cn10k_rng_read.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6c634be2067db06af7b9931abbcfe7507828257f Author: Vladis Dronov <vdronov@xxxxxxxxxx> Date: Wed Apr 13 16:16:05 2022 +0200 hwrng: cn10k - Optimize cn10k_rng_read() [ Upstream commit 753d6770879894de10d74b437ab99ea380f1cad7 ] 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@xxxxxxxxxx> Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/char/hw_random/cn10k-rng.c b/drivers/char/hw_random/cn10k-rng.c index 35001c63648b..dd226630b67d 100644 --- 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 *hwrng, void *data, { 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 *hwrng, void *data, 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;