From 9cc6a94790eecfc808335b759355a4005d66f6e3 Mon Sep 17 00:00:00 2001

From: "Jonathan G. Underwood" <jonathan.underwood@gmail.com>

Date: Tue, 22 Dec 2020 20:04:52 +0000

Subject: [PATCH] cryptsetup: add support for workqueue options

This commit adds support for disabling the read and write

workqueues with the new crypttab options no-read-workqueue

and no-write-workqueue. These correspond to the cryptsetup

options --perf-no_read_workqueue and --perf-no_write_workqueue

respectively.

---

 man/crypttab.xml             | 19 +++++++++++++++++++

 src/cryptsetup/cryptsetup.c  | 12 ++++++++++++

 src/shared/cryptsetup-util.h |  8 ++++++++

 3 files changed, 39 insertions(+)

diff --git a/man/crypttab.xml b/man/crypttab.xml

index 2062a5b8e70..72fe2e692da 100644

--- a/man/crypttab.xml

+++ b/man/crypttab.xml

@@ -342,6 +342,25 @@

         </listitem>

       </varlistentry>

+      <varlistentry>

+        <term><option>no-read-workqueue</option></term>

+

+        <listitem><para>Bypass dm-crypt internal workqueue and process read requests synchronously. The

+        default is to queue these requests and process them asynchronously.</para>

+

+        <para>This requires kernel 5.9 or newer.</para>

+        </listitem>

+      </varlistentry>

+      <varlistentry>

+        <term><option>no-write-workqueue</option></term>

+

+        <listitem><para>Bypass dm-crypt internal workqueue and process write requests synchronously. The

+        default is to queue these requests and process them asynchronously.</para>

+

+        <para>This requires kernel 5.9 or newer.</para>

+        </listitem>

+      </varlistentry>

+

       <varlistentry>

         <term><option>skip=</option></term>

diff --git a/src/cryptsetup/cryptsetup.c b/src/cryptsetup/cryptsetup.c

index 7b21a7457a1..65cbd1aec83 100644

--- a/src/cryptsetup/cryptsetup.c

+++ b/src/cryptsetup/cryptsetup.c

@@ -60,6 +60,8 @@ static bool arg_verify = false;

 static bool arg_discards = false;

 static bool arg_same_cpu_crypt = false;

 static bool arg_submit_from_crypt_cpus = false;

+static bool arg_no_read_workqueue = false;

+static bool arg_no_write_workqueue = false;

 static bool arg_tcrypt_hidden = false;

 static bool arg_tcrypt_system = false;

 static bool arg_tcrypt_veracrypt = false;

@@ -236,6 +238,10 @@ static int parse_one_option(const char *option) {

                 arg_same_cpu_crypt = true;

         else if (streq(option, "submit-from-crypt-cpus"))

                 arg_submit_from_crypt_cpus = true;

+        else if (streq(option, "no-read-workqueue"))

+                arg_no_read_workqueue = true;

+        else if (streq(option, "no-write-workqueue"))

+                arg_no_write_workqueue = true;

         else if (streq(option, "luks"))

                 arg_type = ANY_LUKS;

 /* since cryptsetup 2.3.0 (Feb 2020) */

@@ -1352,6 +1358,12 @@ static uint32_t determine_flags(void) {

         if (arg_submit_from_crypt_cpus)

                 flags |= CRYPT_ACTIVATE_SUBMIT_FROM_CRYPT_CPUS;

+        if (arg_no_read_workqueue)

+                flags |= CRYPT_ACTIVATE_NO_READ_WORKQUEUE;

+

+        if (arg_no_write_workqueue)

+                flags |= CRYPT_ACTIVATE_NO_WRITE_WORKQUEUE;

+

 #ifdef CRYPT_ACTIVATE_SERIALIZE_MEMORY_HARD_PBKDF

         /* Try to decrease the risk of OOM event if memory hard key derivation function is in use */

         /* https://gitlab.com/cryptsetup/cryptsetup/issues/446/ */

diff --git a/src/shared/cryptsetup-util.h b/src/shared/cryptsetup-util.h

index fa2d2f65f3c..afac5cd46bd 100644

--- a/src/shared/cryptsetup-util.h

+++ b/src/shared/cryptsetup-util.h

@@ -7,6 +7,14 @@

 #if HAVE_LIBCRYPTSETUP

 #include <libcryptsetup.h>

+/* These next two are defined in libcryptsetup.h from cryptsetup version 2.3.4 forwards. */

+#ifndef CRYPT_ACTIVATE_NO_READ_WORKQUEUE

+#define CRYPT_ACTIVATE_NO_READ_WORKQUEUE (1 << 24)

+#endif

+#ifndef CRYPT_ACTIVATE_NO_WRITE_WORKQUEUE

+#define CRYPT_ACTIVATE_NO_WRITE_WORKQUEUE (1 << 25)

+#endif

+

 extern int (*sym_crypt_activate_by_passphrase)(struct crypt_device *cd, const char *name, int keyslot, const char *passphrase, size_t passphrase_size, uint32_t flags);

 #if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY

 extern int (*sym_crypt_activate_by_signed_key)(struct crypt_device *cd, const char *name, const char *volume_key, size_t volume_key_size, const char *signature, size_t signature_size, uint32_t flags);