Re: use-sg_init_one-where-appropriate.patch added to -mm tree

From: Herbert Xu
Date: Sat Sep 17 2005 - 02:59:04 EST

On Mon, Aug 29, 2005 at 04:25:57PM -0700, akpm@xxxxxxxx wrote:
>
> From: David Hardeman <david@xxxxxxxx>
>
> This patch uses sg_init_one in some places where it was duplicated.

Thanks for the patch.

In most of the places where a scatterlist is used, we don't care about
the DMA attributes. Hence there is no need to zero the entire scatterlist
structure for them.

I've added a new sg_set_buf function to initialise the address and length
without zeroing the structure. I've also adapted the patch to use it
where appropriate. There were a couple of typos in the crypto code
which I fixed up.

I'll put them into the cryptodev tree.

Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
[PATCH] Introduce sg_set_buf

sg_init_one is a nice tool for the block layer. However, users
of struct scatterlist in other subsystems don't usually need the
DMA attributes. For them it's a waste of time and space to
initialise the whole struct scatterlist structure.

Therefore this patch adds a new function sg_set_buf to initialise
a scatterlist without zeroing the DMA attributes.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -1,14 +1,23 @@
#ifndef _LINUX_SCATTERLIST_H
#define _LINUX_SCATTERLIST_H

-static inline void sg_init_one(struct scatterlist *sg,
- u8 *buf, unsigned int buflen)
-{
- memset(sg, 0, sizeof(*sg));
+#include <asm/scatterlist.h>
+#include <linux/mm.h>
+#include <linux/string.h>

+static inline void sg_set_buf(struct scatterlist *sg, void *buf,
+ unsigned int buflen)
+{
sg->page = virt_to_page(buf);
sg->offset = offset_in_page(buf);
sg->length = buflen;
}

+static inline void sg_init_one(struct scatterlist *sg, void *buf,
+ unsigned int buflen)
+{
+ memset(sg, 0, sizeof(*sg));
+ sg_set_buf(sg, buf, buflen);
+}
+
#endif /* _LINUX_SCATTERLIST_H */
[PATCH] Use sg_set_buf/sg_init_one where applicable

This patch uses sg_set_buf/sg_init_one in some places where it was
duplicated.

Signed-off-by: David Hardeman <david@xxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxx>
Cc: Greg KH <greg@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Jeff Garzik <jgarzik@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/crypto/hmac.c b/crypto/hmac.c
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -18,18 +18,15 @@
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/slab.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
#include "internal.h"

static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
{
struct scatterlist tmp;

- tmp.page = virt_to_page(key);
- tmp.offset = offset_in_page(key);
- tmp.length = keylen;
+ sg_set_buf(&tmp, key, keylen);
crypto_digest_digest(tfm, &tmp, 1, key);
-
}

int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
@@ -69,9 +66,7 @@ void crypto_hmac_init(struct crypto_tfm
for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
ipad[i] ^= 0x36;

- tmp.page = virt_to_page(ipad);
- tmp.offset = offset_in_page(ipad);
- tmp.length = crypto_tfm_alg_blocksize(tfm);
+ sg_set_buf(&tmp, ipad, crypto_tfm_alg_blocksize(tfm));

crypto_digest_init(tfm);
crypto_digest_update(tfm, &tmp, 1);
@@ -103,16 +98,12 @@ void crypto_hmac_final(struct crypto_tfm
for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
opad[i] ^= 0x5c;

- tmp.page = virt_to_page(opad);
- tmp.offset = offset_in_page(opad);
- tmp.length = crypto_tfm_alg_blocksize(tfm);
+ sg_set_buf(&tmp, opad, crypto_tfm_alg_blocksize(tfm));

crypto_digest_init(tfm);
crypto_digest_update(tfm, &tmp, 1);

- tmp.page = virt_to_page(out);
- tmp.offset = offset_in_page(out);
- tmp.length = crypto_tfm_alg_digestsize(tfm);
+ sg_set_buf(&tmp, out, crypto_tfm_alg_digestsize(tfm));

crypto_digest_update(tfm, &tmp, 1);
crypto_digest_final(tfm, out);
diff --git a/crypto/tcrypt.c b/crypto/tcrypt.c
--- a/crypto/tcrypt.c
+++ b/crypto/tcrypt.c
@@ -21,7 +21,7 @@
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/slab.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
#include <linux/string.h>
#include <linux/crypto.h>
#include <linux/highmem.h>
@@ -86,7 +86,6 @@ static void hexdump(unsigned char *buf,
static void test_hash(char *algo, struct hash_testvec *template,
unsigned int tcount)
{
- char *p;
unsigned int i, j, k, temp;
struct scatterlist sg[8];
char result[64];
@@ -116,10 +115,7 @@ static void test_hash(char *algo, struct
printk("test %u:\n", i + 1);
memset(result, 0, 64);

- p = hash_tv[i].plaintext;
- sg[0].page = virt_to_page(p);
- sg[0].offset = offset_in_page(p);
- sg[0].length = hash_tv[i].psize;
+ sg_set_buf(&sg[0], hash_tv[i].plaintext, hash_tv[i].psize);

crypto_digest_init(tfm);
if (tfm->crt_u.digest.dit_setkey) {
@@ -154,10 +150,8 @@ static void test_hash(char *algo, struct
hash_tv[i].plaintext + temp,
hash_tv[i].tap[k]);
temp += hash_tv[i].tap[k];
- p = &xbuf[IDX[k]];
- sg[k].page = virt_to_page(p);
- sg[k].offset = offset_in_page(p);
- sg[k].length = hash_tv[i].tap[k];
+ sg_set_buf(&sg[k], &xbuf[IDX[k]],
+ hash_tv[i].tap[k]);
}

crypto_digest_digest(tfm, sg, hash_tv[i].np, result);
@@ -179,7 +173,6 @@ static void test_hash(char *algo, struct
static void test_hmac(char *algo, struct hmac_testvec *template,
unsigned int tcount)
{
- char *p;
unsigned int i, j, k, temp;
struct scatterlist sg[8];
char result[64];
@@ -210,11 +203,8 @@ static void test_hmac(char *algo, struct
printk("test %u:\n", i + 1);
memset(result, 0, sizeof (result));

- p = hmac_tv[i].plaintext;
klen = hmac_tv[i].ksize;
- sg[0].page = virt_to_page(p);
- sg[0].offset = offset_in_page(p);
- sg[0].length = hmac_tv[i].psize;
+ sg_set_buf(&sg[0], hmac_tv[i].plaintext, hmac_tv[i].psize);

crypto_hmac(tfm, hmac_tv[i].key, &klen, sg, 1, result);

@@ -243,10 +233,8 @@ static void test_hmac(char *algo, struct
hmac_tv[i].plaintext + temp,
hmac_tv[i].tap[k]);
temp += hmac_tv[i].tap[k];
- p = &xbuf[IDX[k]];
- sg[k].page = virt_to_page(p);
- sg[k].offset = offset_in_page(p);
- sg[k].length = hmac_tv[i].tap[k];
+ sg_set_buf(&sg[k], &xbuf[IDX[k]],
+ hmac_tv[i].tap[k]);
}

crypto_hmac(tfm, hmac_tv[i].key, &klen, sg,
@@ -270,7 +258,7 @@ static void test_cipher(char *algo, int
{
unsigned int ret, i, j, k, temp;
unsigned int tsize;
- char *p, *q;
+ char *q;
struct crypto_tfm *tfm;
char *key;
struct cipher_testvec *cipher_tv;
@@ -330,10 +318,8 @@ static void test_cipher(char *algo, int
goto out;
}

- p = cipher_tv[i].input;
- sg[0].page = virt_to_page(p);
- sg[0].offset = offset_in_page(p);
- sg[0].length = cipher_tv[i].ilen;
+ sg_set_buf(&sg[0], cipher_tv[i].input,
+ cipher_tv[i].ilen);

if (!mode) {
crypto_cipher_set_iv(tfm, cipher_tv[i].iv,
@@ -389,10 +375,8 @@ static void test_cipher(char *algo, int
cipher_tv[i].input + temp,
cipher_tv[i].tap[k]);
temp += cipher_tv[i].tap[k];
- p = &xbuf[IDX[k]];
- sg[k].page = virt_to_page(p);
- sg[k].offset = offset_in_page(p);
- sg[k].length = cipher_tv[i].tap[k];
+ sg_set_buf(&sg[k], &xbuf[IDX[k]],
+ cipher_tv[i].tap[k]);
}

if (!mode) {
@@ -436,9 +420,7 @@ static int test_cipher_jiffies(struct cr
int bcount;
int ret;

- sg[0].page = virt_to_page(p);
- sg[0].offset = offset_in_page(p);
- sg[0].length = blen;
+ sg_set_buf(&sg[0], p, blen);

for (start = jiffies, end = start + sec * HZ, bcount = 0;
time_before(jiffies, end); bcount++) {
@@ -464,9 +446,7 @@ static int test_cipher_cycles(struct cry
int ret = 0;
int i;

- sg[0].page = virt_to_page(p);
- sg[0].offset = offset_in_page(p);
- sg[0].length = blen;
+ sg_set_buf(&sg[0], p, blen);

local_bh_disable();
local_irq_disable();
@@ -709,9 +689,7 @@ static void test_crc32c(void)
for (i = 0; i < NUMVEC; i++) {
for (j = 0; j < VECSIZE; j++)
test_vec[i][j] = ++b;
- sg[i].page = virt_to_page(test_vec[i]);
- sg[i].offset = offset_in_page(test_vec[i]);
- sg[i].length = VECSIZE;
+ sg_set_buf(&sg[i], test_vec[i], VECSIZE);
}

seed = SEEDTESTVAL;
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -15,7 +15,7 @@
#include <linux/crypto.h>
#include <linux/workqueue.h>
#include <asm/atomic.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
#include <asm/page.h>

#include "dm.h"
@@ -164,9 +164,7 @@ static int crypt_iv_essiv_ctr(struct cry
return -ENOMEM;
}

- sg.page = virt_to_page(cc->key);
- sg.offset = offset_in_page(cc->key);
- sg.length = cc->key_size;
+ sg_set_buf(&sg, cc->key, cc->key_size);
crypto_digest_digest(hash_tfm, &sg, 1, salt);
crypto_free_tfm(hash_tfm);

@@ -207,14 +205,12 @@ static void crypt_iv_essiv_dtr(struct cr

static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
- struct scatterlist sg = { NULL, };
+ struct scatterlist sg;

memset(iv, 0, cc->iv_size);
*(u64 *)iv = cpu_to_le64(sector);

- sg.page = virt_to_page(iv);
- sg.offset = offset_in_page(iv);
- sg.length = cc->iv_size;
+ sg_set_buf(&sg, iv, cc->iv_size);
crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private,
&sg, &sg, cc->iv_size);

diff --git a/drivers/net/wireless/airo.c b/drivers/net/wireless/airo.c
--- a/drivers/net/wireless/airo.c
+++ b/drivers/net/wireless/airo.c
@@ -35,6 +35,7 @@
#include <linux/interrupt.h>
#include <linux/in.h>
#include <linux/bitops.h>
+#include <linux/scatterlist.h>
#include <asm/io.h>
#include <asm/system.h>

@@ -1596,9 +1597,7 @@ static void emmh32_setseed(emmh32_contex
aes_counter[12] = (u8)(counter >> 24);
counter++;
memcpy (plain, aes_counter, 16);
- sg[0].page = virt_to_page(plain);
- sg[0].offset = ((long) plain & ~PAGE_MASK);
- sg[0].length = 16;
+ sg_set_buf(&sg[0], plain, 16);
crypto_cipher_encrypt(tfm, sg, sg, 16);
cipher = kmap(sg[0].page) + sg[0].offset;
for (j=0; (j<16) && (i< (sizeof(context->coeff)/sizeof(context->coeff[0]))); ) {
diff --git a/drivers/scsi/arm/scsi.h b/drivers/scsi/arm/scsi.h
--- a/drivers/scsi/arm/scsi.h
+++ b/drivers/scsi/arm/scsi.h
@@ -10,6 +10,8 @@
* Commonly used scsi driver functions.
*/

+#include <linux/scatterlist.h>
+
#define BELT_AND_BRACES

/*
@@ -22,9 +24,7 @@ static inline int copy_SCp_to_sg(struct

BUG_ON(bufs + 1 > max);

- sg->page = virt_to_page(SCp->ptr);
- sg->offset = offset_in_page(SCp->ptr);
- sg->length = SCp->this_residual;
+ sg_set_buf(sg, SCp->ptr, SCp->this_residual);

if (bufs)
memcpy(sg + 1, SCp->buffer + 1,
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -48,6 +48,7 @@
#include <linux/completion.h>
#include <linux/suspend.h>
#include <linux/workqueue.h>
+#include <linux/scatterlist.h>
#include <scsi/scsi.h>
#include "scsi.h"
#include "scsi_priv.h"
@@ -2284,19 +2285,12 @@ void ata_qc_prep(struct ata_queued_cmd *

void ata_sg_init_one(struct ata_queued_cmd *qc, void *buf, unsigned int buflen)
{
- struct scatterlist *sg;
-
qc->flags |= ATA_QCFLAG_SINGLE;

- memset(&qc->sgent, 0, sizeof(qc->sgent));
qc->sg = &qc->sgent;
qc->n_elem = 1;
qc->buf_virt = buf;
-
- sg = qc->sg;
- sg->page = virt_to_page(buf);
- sg->offset = (unsigned long) buf & ~PAGE_MASK;
- sg->length = buflen;
+ sg_init_one(qc->sg, buf, buflen);
}

/**
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -49,6 +49,7 @@ static int sg_version_num = 30533; /* 2
#include <linux/seq_file.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
+#include <linux/scatterlist.h>

#include "scsi.h"
#include <scsi/scsi_dbg.h>
@@ -1992,9 +1993,7 @@ sg_build_indirect(Sg_scatter_hold * schp
if (!p)
break;
}
- sclp->page = virt_to_page(p);
- sclp->offset = offset_in_page(p);
- sclp->length = ret_sz;
+ sg_set_buf(sclp, p, ret_sz);

SCSI_LOG_TIMEOUT(5, printk("sg_build_build: k=%d, a=0x%p, len=%d\n",
k, sg_scatg2virt(sclp), ret_sz));
diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -9,7 +9,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>

#include <linux/usb.h>

@@ -381,7 +381,6 @@ alloc_sglist (int nents, int max, int va
sg = kmalloc (nents * sizeof *sg, SLAB_KERNEL);
if (!sg)
return NULL;
- memset (sg, 0, nents * sizeof *sg);

for (i = 0; i < nents; i++) {
char *buf;
@@ -394,9 +393,7 @@ alloc_sglist (int nents, int max, int va
memset (buf, 0, size);

/* kmalloc pages are always physically contiguous! */
- sg [i].page = virt_to_page (buf);
- sg [i].offset = offset_in_page (buf);
- sg [i].length = size;
+ sg_init_one(&sg[i], buf, size);

if (vary) {
size += vary;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -75,7 +75,7 @@
#ifdef CONFIG_IPV6_PRIVACY
#include <linux/random.h>
#include <linux/crypto.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
#endif

#include <asm/uaccess.h>
@@ -1217,12 +1217,8 @@ static int __ipv6_regen_rndid(struct ine
struct net_device *dev;
struct scatterlist sg[2];

- sg[0].page = virt_to_page(idev->entropy);
- sg[0].offset = offset_in_page(idev->entropy);
- sg[0].length = 8;
- sg[1].page = virt_to_page(idev->work_eui64);
- sg[1].offset = offset_in_page(idev->work_eui64);
- sg[1].length = 8;
+ sg_set_buf(&sg[0], idev->entropy, 8);
+ sg_set_buf(&sg[1], idev->work_eui64, 8);

dev = idev->dev;

diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -37,7 +37,7 @@
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/slab.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
@@ -75,9 +75,7 @@ krb5_encrypt(
memcpy(local_iv, iv, crypto_tfm_alg_ivsize(tfm));

memcpy(out, in, length);
- sg[0].page = virt_to_page(out);
- sg[0].offset = offset_in_page(out);
- sg[0].length = length;
+ sg_set_buf(&sg[0], out, length);

ret = crypto_cipher_encrypt_iv(tfm, sg, sg, length, local_iv);

@@ -117,9 +115,7 @@ krb5_decrypt(
memcpy(local_iv,iv, crypto_tfm_alg_ivsize(tfm));

memcpy(out, in, length);
- sg[0].page = virt_to_page(out);
- sg[0].offset = offset_in_page(out);
- sg[0].length = length;
+ sg_set_buf(&sg[0], out, length);

ret = crypto_cipher_decrypt_iv(tfm, sg, sg, length, local_iv);

@@ -132,13 +128,6 @@ out:

EXPORT_SYMBOL(krb5_decrypt);

-static void
-buf_to_sg(struct scatterlist *sg, char *ptr, int len) {
- sg->page = virt_to_page(ptr);
- sg->offset = offset_in_page(ptr);
- sg->length = len;
-}
-
/* checksum the plaintext data and hdrlen bytes of the token header */
s32
make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
@@ -167,10 +156,10 @@ make_checksum(s32 cksumtype, char *heade
goto out;

crypto_digest_init(tfm);
- buf_to_sg(sg, header, hdrlen);
+ sg_set_buf(sg, header, hdrlen);
crypto_digest_update(tfm, sg, 1);
if (body->head[0].iov_len) {
- buf_to_sg(sg, body->head[0].iov_base, body->head[0].iov_len);
+ sg_set_buf(sg, body->head[0].iov_base, body->head[0].iov_len);
crypto_digest_update(tfm, sg, 1);
}

@@ -193,7 +182,7 @@ make_checksum(s32 cksumtype, char *heade
} while(len != 0);
}
if (body->tail[0].iov_len) {
- buf_to_sg(sg, body->tail[0].iov_base, body->tail[0].iov_len);
+ sg_set_buf(sg, body->tail[0].iov_base, body->tail[0].iov_len);
crypto_digest_update(tfm, sg, 1);
}
crypto_digest_final(tfm, cksum->data);