[PATCH v2 18/18] scsi: target: iscsi: switch to using the crc32c library

Eric Biggers
2024-10-25T19:15:54Z

From: Eric Biggers <ebiggers@google.com>

Now that the crc32c() library function directly takes advantage of
architecture-specific optimizations, it is unnecessary to go through the
crypto API. Just use crc32c(). This is much simpler, and it improves
performance due to eliminating the crypto API overhead.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
drivers/target/iscsi/Kconfig | 2 +-
drivers/target/iscsi/iscsi_target.c | 153 +++++++---------------
drivers/target/iscsi/iscsi_target_login.c | 50 -------
drivers/target/iscsi/iscsi_target_login.h | 1 -
drivers/target/iscsi/iscsi_target_nego.c | 21 +--
include/target/iscsi/iscsi_target_core.h | 3 -
6 files changed, 48 insertions(+), 182 deletions(-)

diff --git a/drivers/target/iscsi/Kconfig b/drivers/target/iscsi/Kconfig
index 1c0517a12571..2f2f3dc831b8 100644
--- a/drivers/target/iscsi/Kconfig
+++ b/drivers/target/iscsi/Kconfig
@@ -1,11 +1,11 @@
# SPDX-License-Identifier: GPL-2.0-only
config ISCSI_TARGET
tristate "SCSI Target Mode Stack"
depends on INET
+ select CRC32
select CRYPTO
- select CRYPTO_CRC32C
help
Say M to enable the SCSI target mode stack. A SCSI target mode stack
is software that makes local storage available over a storage network
to a SCSI initiator system. The supported storage network technologies
include iSCSI, Fibre Channel and the SCSI RDMA Protocol (SRP).
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 6002283cbeba..091c1efccfb7 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -6,11 +6,11 @@
*
* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
*
******************************************************************************/

-#include <crypto/hash.h>
+#include <linux/crc32c.h>
#include <linux/string.h>
#include <linux/kthread.h>
#include <linux/completion.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
@@ -488,12 +488,12 @@ void iscsit_aborted_task(struct iscsit_conn *conn, struct iscsit_cmd *cmd)

__iscsit_free_cmd(cmd, true);
}
EXPORT_SYMBOL(iscsit_aborted_task);

-static void iscsit_do_crypto_hash_buf(struct ahash_request *, const void *,
- u32, u32, const void *, void *);
+static u32 iscsit_crc_buf(const void *buf, u32 payload_length,
+ u32 padding, const void *pad_bytes);
static void iscsit_tx_thread_wait_for_tcp(struct iscsit_conn *);

static int
iscsit_xmit_nondatain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
const void *data_buf, u32 data_buf_len)
@@ -508,13 +508,11 @@ iscsit_xmit_nondatain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
iov[niov++].iov_len = ISCSI_HDR_LEN;

if (conn->conn_ops->HeaderDigest) {
u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

- iscsit_do_crypto_hash_buf(conn->conn_tx_hash, hdr,
- ISCSI_HDR_LEN, 0, NULL,
- header_digest);
+ *header_digest = iscsit_crc_buf(hdr, ISCSI_HDR_LEN, 0, NULL);

iov[0].iov_len += ISCSI_CRC_LEN;
tx_size += ISCSI_CRC_LEN;
pr_debug("Attaching CRC32C HeaderDigest"
" to opcode 0x%x 0x%08x\n",
@@ -535,15 +533,13 @@ iscsit_xmit_nondatain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
pr_debug("Attaching %u additional"
" padding bytes.\n", padding);
}

if (conn->conn_ops->DataDigest) {
- iscsit_do_crypto_hash_buf(conn->conn_tx_hash,
- data_buf, data_buf_len,
- padding, &cmd->pad_bytes,
- &cmd->data_crc);
-
+ cmd->data_crc = iscsit_crc_buf(data_buf, data_buf_len,
+ padding,
+ &cmd->pad_bytes);
iov[niov].iov_base = &cmd->data_crc;
iov[niov++].iov_len = ISCSI_CRC_LEN;
tx_size += ISCSI_CRC_LEN;
pr_debug("Attached DataDigest for %u"
" bytes opcode 0x%x, CRC 0x%08x\n",
@@ -564,12 +560,12 @@ iscsit_xmit_nondatain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
}

static int iscsit_map_iovec(struct iscsit_cmd *cmd, struct kvec *iov, int nvec,
u32 data_offset, u32 data_length);
static void iscsit_unmap_iovec(struct iscsit_cmd *);
-static u32 iscsit_do_crypto_hash_sg(struct ahash_request *, struct iscsit_cmd *,
- u32, u32, u32, u8 *);
+static u32 iscsit_crc_sglist(const struct iscsit_cmd *cmd, u32 data_length,
+ u32 padding, const u8 *pad_bytes);
static int
iscsit_xmit_datain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
const struct iscsi_datain *datain)
{
struct kvec *iov;
@@ -582,14 +578,12 @@ iscsit_xmit_datain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
tx_size += ISCSI_HDR_LEN;

if (conn->conn_ops->HeaderDigest) {
u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

- iscsit_do_crypto_hash_buf(conn->conn_tx_hash, cmd->pdu,
- ISCSI_HDR_LEN, 0, NULL,
- header_digest);
-
+ *header_digest = iscsit_crc_buf(cmd->pdu, ISCSI_HDR_LEN, 0,
+ NULL);
iov[0].iov_len += ISCSI_CRC_LEN;
tx_size += ISCSI_CRC_LEN;

pr_debug("Attaching CRC32 HeaderDigest for DataIN PDU 0x%08x\n",
*header_digest);
@@ -612,16 +606,12 @@ iscsit_xmit_datain_pdu(struct iscsit_conn *conn, struct iscsit_cmd *cmd,

pr_debug("Attaching %u padding bytes\n", cmd->padding);
}

if (conn->conn_ops->DataDigest) {
- cmd->data_crc = iscsit_do_crypto_hash_sg(conn->conn_tx_hash,
- cmd, datain->offset,
- datain->length,
- cmd->padding,
- cmd->pad_bytes);
-
+ cmd->data_crc = iscsit_crc_sglist(cmd, datain->length,
+ cmd->padding, cmd->pad_bytes);
iov[iov_count].iov_base = &cmd->data_crc;
iov[iov_count++].iov_len = ISCSI_CRC_LEN;
tx_size += ISCSI_CRC_LEN;

pr_debug("Attached CRC32C DataDigest %d bytes, crc 0x%08x\n",
@@ -1402,81 +1392,49 @@ iscsit_handle_scsi_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
return 0;

return iscsit_get_immediate_data(cmd, hdr, dump_payload);
}

-static u32 iscsit_do_crypto_hash_sg(
- struct ahash_request *hash,
- struct iscsit_cmd *cmd,
- u32 data_offset,
- u32 data_length,
- u32 padding,
- u8 *pad_bytes)
+static u32 iscsit_crc_sglist(const struct iscsit_cmd *cmd, u32 data_length,
+ u32 padding, const u8 *pad_bytes)
{
- u32 data_crc;
- struct scatterlist *sg;
- unsigned int page_off;
-
- crypto_ahash_init(hash);
-
- sg = cmd->first_data_sg;
- page_off = cmd->first_data_sg_off;
-
- if (data_length && page_off) {
- struct scatterlist first_sg;
- u32 len = min_t(u32, data_length, sg->length - page_off);
-
- sg_init_table(&first_sg, 1);
- sg_set_page(&first_sg, sg_page(sg), len, sg->offset + page_off);
-
- ahash_request_set_crypt(hash, &first_sg, NULL, len);
- crypto_ahash_update(hash);
-
- data_length -= len;
- sg = sg_next(sg);
- }
+ struct scatterlist *sg = cmd->first_data_sg;
+ unsigned int page_off = cmd->first_data_sg_off;
+ u32 crc = ~0;

while (data_length) {
- u32 cur_len = min_t(u32, data_length, sg->length);
+ u32 cur_len = min_t(u32, data_length, sg->length - page_off);
+ const void *virt;

- ahash_request_set_crypt(hash, sg, NULL, cur_len);
- crypto_ahash_update(hash);
+ virt = kmap_local_page(sg_page(sg)) + sg->offset + page_off;
+ crc = crc32c(crc, virt, cur_len);
+ kunmap_local(virt);

- data_length -= cur_len;
/* iscsit_map_iovec has already checked for invalid sg pointers */
sg = sg_next(sg);
- }

- if (padding) {
- struct scatterlist pad_sg;
-
- sg_init_one(&pad_sg, pad_bytes, padding);
- ahash_request_set_crypt(hash, &pad_sg, (u8 *)&data_crc,
- padding);
- crypto_ahash_finup(hash);
- } else {
- ahash_request_set_crypt(hash, NULL, (u8 *)&data_crc, 0);
- crypto_ahash_final(hash);
+ page_off = 0;
+ data_length -= cur_len;
}

- return data_crc;
+ if (padding)
+ crc = crc32c(crc, pad_bytes, padding);
+
+ return ~crc;
}

-static void iscsit_do_crypto_hash_buf(struct ahash_request *hash,
- const void *buf, u32 payload_length, u32 padding,
- const void *pad_bytes, void *data_crc)
+static u32 iscsit_crc_buf(const void *buf, u32 payload_length,
+ u32 padding, const void *pad_bytes)
{
- struct scatterlist sg[2];
+ u32 crc = ~0;

- sg_init_table(sg, ARRAY_SIZE(sg));
- sg_set_buf(sg, buf, payload_length);
- if (padding)
- sg_set_buf(sg + 1, pad_bytes, padding);
+ crc = crc32c(crc, buf, payload_length);

- ahash_request_set_crypt(hash, sg, data_crc, payload_length + padding);
+ if (padding)
+ crc = crc32c(crc, pad_bytes, padding);

- crypto_ahash_digest(hash);
+ return ~crc;
}

int
__iscsit_check_dataout_hdr(struct iscsit_conn *conn, void *buf,
struct iscsit_cmd *cmd, u32 payload_length,
@@ -1660,15 +1618,12 @@ iscsit_get_dataout(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
return -1;

if (conn->conn_ops->DataDigest) {
u32 data_crc;

- data_crc = iscsit_do_crypto_hash_sg(conn->conn_rx_hash, cmd,
- be32_to_cpu(hdr->offset),
- payload_length, padding,
- cmd->pad_bytes);
-
+ data_crc = iscsit_crc_sglist(cmd, payload_length, padding,
+ cmd->pad_bytes);
if (checksum != data_crc) {
pr_err("ITT: 0x%08x, Offset: %u, Length: %u,"
" DataSN: 0x%08x, CRC32C DataDigest 0x%08x"
" does not match computed 0x%08x\n",
hdr->itt, hdr->offset, payload_length,
@@ -1923,14 +1878,12 @@ static int iscsit_handle_nop_out(struct iscsit_conn *conn, struct iscsit_cmd *cm
ret = -1;
goto out;
}

if (conn->conn_ops->DataDigest) {
- iscsit_do_crypto_hash_buf(conn->conn_rx_hash, ping_data,
- payload_length, padding,
- cmd->pad_bytes, &data_crc);
-
+ data_crc = iscsit_crc_buf(ping_data, payload_length,
+ padding, cmd->pad_bytes);
if (checksum != data_crc) {
pr_err("Ping data CRC32C DataDigest"
" 0x%08x does not match computed 0x%08x\n",
checksum, data_crc);
if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
@@ -2326,14 +2279,11 @@ iscsit_handle_text_cmd(struct iscsit_conn *conn, struct iscsit_cmd *cmd,
rx_got = rx_data(conn, &iov[0], niov, rx_size);
if (rx_got != rx_size)
goto reject;

if (conn->conn_ops->DataDigest) {
- iscsit_do_crypto_hash_buf(conn->conn_rx_hash,
- text_in, rx_size, 0, NULL,
- &data_crc);
-
+ data_crc = iscsit_crc_buf(text_in, rx_size, 0, NULL);
if (checksum != data_crc) {
pr_err("Text data CRC32C DataDigest"
" 0x%08x does not match computed"
" 0x%08x\n", checksum, data_crc);
if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
@@ -2686,14 +2636,12 @@ static int iscsit_handle_immediate_data(
}

if (conn->conn_ops->DataDigest) {
u32 data_crc;

- data_crc = iscsit_do_crypto_hash_sg(conn->conn_rx_hash, cmd,
- cmd->write_data_done, length, padding,
- cmd->pad_bytes);
-
+ data_crc = iscsit_crc_sglist(cmd, length, padding,
+ cmd->pad_bytes);
if (checksum != data_crc) {
pr_err("ImmediateData CRC32C DataDigest 0x%08x"
" does not match computed 0x%08x\n", checksum,
data_crc);

@@ -4114,14 +4062,12 @@ static void iscsit_get_rx_pdu(struct iscsit_conn *conn)
if (ret != ISCSI_CRC_LEN) {
iscsit_rx_thread_wait_for_tcp(conn);
break;
}

- iscsit_do_crypto_hash_buf(conn->conn_rx_hash, buffer,
- ISCSI_HDR_LEN, 0, NULL,
- &checksum);
-
+ checksum = iscsit_crc_buf(buffer, ISCSI_HDR_LEN, 0,
+ NULL);
if (digest != checksum) {
pr_err("HeaderDigest CRC32C failed,"
" received 0x%08x, computed 0x%08x\n",
digest, checksum);
/*
@@ -4404,19 +4350,10 @@ int iscsit_close_connection(
* If any other processes are accessing this connection pointer we
* must wait until they have completed.
*/
iscsit_check_conn_usage_count(conn);

- ahash_request_free(conn->conn_tx_hash);
- if (conn->conn_rx_hash) {
- struct crypto_ahash *tfm;
-
- tfm = crypto_ahash_reqtfm(conn->conn_rx_hash);
- ahash_request_free(conn->conn_rx_hash);
- crypto_free_ahash(tfm);
- }
-
if (conn->sock)
sock_release(conn->sock);

if (conn->conn_transport->iscsit_free_conn)
conn->conn_transport->iscsit_free_conn(conn);
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 90b870f234f0..c2ac9a99ebbb 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -6,11 +6,10 @@
*
* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
*
******************************************************************************/

-#include <crypto/hash.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kthread.h>
#include <linux/sched/signal.h>
#include <linux/idr.h>
@@ -69,50 +68,10 @@ static struct iscsi_login *iscsi_login_init_conn(struct iscsit_conn *conn)
out_login:
kfree(login);
return NULL;
}

-/*
- * Used by iscsi_target_nego.c:iscsi_target_locate_portal() to setup
- * per struct iscsit_conn libcrypto contexts for crc32c and crc32-intel
- */
-int iscsi_login_setup_crypto(struct iscsit_conn *conn)
-{
- struct crypto_ahash *tfm;
-
- /*
- * Setup slicing by CRC32C algorithm for RX and TX libcrypto contexts
- * which will default to crc32c_intel.ko for cpu_has_xmm4_2, or fallback
- * to software 1x8 byte slicing from crc32c.ko
- */
- tfm = crypto_alloc_ahash("crc32c", 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(tfm)) {
- pr_err("crypto_alloc_ahash() failed\n");
- return -ENOMEM;
- }
-
- conn->conn_rx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
- if (!conn->conn_rx_hash) {
- pr_err("ahash_request_alloc() failed for conn_rx_hash\n");
- crypto_free_ahash(tfm);
- return -ENOMEM;
- }
- ahash_request_set_callback(conn->conn_rx_hash, 0, NULL, NULL);
-
- conn->conn_tx_hash = ahash_request_alloc(tfm, GFP_KERNEL);
- if (!conn->conn_tx_hash) {
- pr_err("ahash_request_alloc() failed for conn_tx_hash\n");
- ahash_request_free(conn->conn_rx_hash);
- conn->conn_rx_hash = NULL;
- crypto_free_ahash(tfm);
- return -ENOMEM;
- }
- ahash_request_set_callback(conn->conn_tx_hash, 0, NULL, NULL);
-
- return 0;
-}
-
static int iscsi_login_check_initiator_version(
struct iscsit_conn *conn,
u8 version_max,
u8 version_min)
{
@@ -1163,19 +1122,10 @@ void iscsi_target_login_sess_out(struct iscsit_conn *conn,
} else
spin_unlock_bh(&conn->sess->conn_lock);
iscsit_dec_session_usage_count(conn->sess);
}

- ahash_request_free(conn->conn_tx_hash);
- if (conn->conn_rx_hash) {
- struct crypto_ahash *tfm;
-
- tfm = crypto_ahash_reqtfm(conn->conn_rx_hash);
- ahash_request_free(conn->conn_rx_hash);
- crypto_free_ahash(tfm);
- }
-
if (conn->param_list) {
iscsi_release_param_list(conn->param_list);
conn->param_list = NULL;
}
iscsi_target_nego_release(conn);
diff --git a/drivers/target/iscsi/iscsi_target_login.h b/drivers/target/iscsi/iscsi_target_login.h
index e8760735486b..03c7d695d58f 100644
--- a/drivers/target/iscsi/iscsi_target_login.h
+++ b/drivers/target/iscsi/iscsi_target_login.h
@@ -7,11 +7,10 @@
struct iscsit_conn;
struct iscsi_login;
struct iscsi_np;
struct sockaddr_storage;

-extern int iscsi_login_setup_crypto(struct iscsit_conn *);
extern int iscsi_check_for_session_reinstatement(struct iscsit_conn *);
extern int iscsi_login_post_auth_non_zero_tsih(struct iscsit_conn *, u16, u32);
extern int iscsit_setup_np(struct iscsi_np *,
struct sockaddr_storage *);
extern int iscsi_target_setup_login_socket(struct iscsi_np *,
diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index fa3fb5f4e6bc..16e3ded98c32 100644
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -1192,18 +1192,11 @@ int iscsi_target_locate_portal(
if (!sessiontype) {
if (!login->leading_connection)
goto get_target;

sess->sess_ops->SessionType = 1;
- /*
- * Setup crc32c modules from libcrypto
- */
- if (iscsi_login_setup_crypto(conn) < 0) {
- pr_err("iscsi_login_setup_crypto() failed\n");
- ret = -1;
- goto out;
- }
+
/*
* Serialize access across the discovery struct iscsi_portal_group to
* process login attempt.
*/
conn->tpg = iscsit_global->discovery_tpg;
@@ -1256,21 +1249,11 @@ int iscsi_target_locate_portal(
ret = -1;
goto out;
}
conn->tpg_np = tpg_np;
pr_debug("Located Portal Group Object: %hu\n", conn->tpg->tpgt);
- /*
- * Setup crc32c modules from libcrypto
- */
- if (iscsi_login_setup_crypto(conn) < 0) {
- pr_err("iscsi_login_setup_crypto() failed\n");
- kref_put(&tpg_np->tpg_np_kref, iscsit_login_kref_put);
- iscsit_put_tiqn_for_login(tiqn);
- conn->tpg = NULL;
- ret = -1;
- goto out;
- }
+
/*
* Serialize access across the struct iscsi_portal_group to
* process login attempt.
*/
if (iscsit_access_np(np, conn->tpg) < 0) {
diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index 60af7c63b34e..51ca80abacf7 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -574,13 +574,10 @@ struct iscsit_conn {
spinlock_t nopin_timer_lock;
spinlock_t response_queue_lock;
spinlock_t state_lock;
spinlock_t login_timer_lock;
spinlock_t login_worker_lock;
- /* libcrypto RX and TX contexts for crc32c */
- struct ahash_request *conn_rx_hash;
- struct ahash_request *conn_tx_hash;
/* Used for scheduling TX and RX connection kthreads */
cpumask_var_t conn_cpumask;
cpumask_var_t allowed_cpumask;
unsigned int conn_rx_reset_cpumask:1;
unsigned int conn_tx_reset_cpumask:1;
--
2.47.0