Patch "crypto: crypto4xx - increase context and scatter ring buffer elements" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

crypto: crypto4xx - increase context and scatter ring buffer elements

to the 4.4-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:
crypto-crypto4xx-increase-context-and-scatter-ring-buffer-elements.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Christian Lamparter <[email protected]>
Date: Wed, 4 Oct 2017 01:00:08 +0200
Subject: crypto: crypto4xx - increase context and scatter ring buffer elements

From: Christian Lamparter <[email protected]>

[ Upstream commit 778f81d6cdb7d25360f082ac0384d5103f04eca5 ]

If crypto4xx is used in conjunction with dm-crypt, the available ring buffer elements are not enough to handle the load properly.

On an aes-cbc-essiv:sha256 encrypted swap partition the read performance is abyssal: (tested with hdparm -t)

/dev/mapper/swap_crypt:
Timing buffered disk reads: 14 MB in 3.68 seconds = 3.81 MB/sec

The patch increases both PPC4XX_NUM_SD and PPC4XX_NUM_PD to 256. This improves the performance considerably:

/dev/mapper/swap_crypt:
Timing buffered disk reads: 104 MB in 3.03 seconds = 34.31 MB/sec

Furthermore, PPC4XX_LAST_SD, PPC4XX_LAST_GD and PPC4XX_LAST_PD can be easily calculated from their respective PPC4XX_NUM_* constant.

---
 drivers/crypto/amcc/crypto4xx_core.h |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

@@ -32,12 +32,12 @@
 #define PPC405EX_CE_RESET                       0x00000008
 
 #define CRYPTO4XX_CRYPTO_PRIORITY		300
-#define PPC4XX_LAST_PD				63
-#define PPC4XX_NUM_PD				64
-#define PPC4XX_LAST_GD				1023
+#define PPC4XX_NUM_PD				256
+#define PPC4XX_LAST_PD				(PPC4XX_NUM_PD - 1)
 #define PPC4XX_NUM_GD				1024
-#define PPC4XX_LAST_SD				63
-#define PPC4XX_NUM_SD				64
+#define PPC4XX_LAST_GD				(PPC4XX_NUM_GD - 1)
+#define PPC4XX_NUM_SD				256
+#define PPC4XX_LAST_SD				(PPC4XX_NUM_SD - 1)
 #define PPC4XX_SD_BUFFER_SIZE			2048
 
 #define PD_ENTRY_INUSE				1

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/crypto-crypto4xx-increase-context-and-scatter-ring-buffer-elements.patch