Patch "hwrng: cn10k - Optimize cn10k_rng_read()" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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;