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Al Viro
committed
net/9p: switch the guts of p9_client_{read,write}() to iov_iter
... and have get_user_pages_fast() mapping fewer pages than requested to generate a short read/write. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1 parent 6e242a1 commit 4f3b35c

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4 files changed

+147
-133
lines changed

4 files changed

+147
-133
lines changed

‎include/net/9p/transport.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -61,7 +61,7 @@ struct p9_trans_module {
6161
int (*cancel) (struct p9_client *, struct p9_req_t *req);
6262
int (*cancelled)(struct p9_client *, struct p9_req_t *req);
6363
int (*zc_request)(struct p9_client *, struct p9_req_t *,
64-
char *, char *, int , int, int, int);
64+
struct iov_iter *, struct iov_iter *, int , int, int);
6565
};
6666

6767
void v9fs_register_trans(struct p9_trans_module *m);

‎net/9p/client.c

Lines changed: 59 additions & 58 deletions
Original file line numberDiff line numberDiff line change
@@ -34,6 +34,7 @@
3434
#include <linux/slab.h>
3535
#include <linux/sched.h>
3636
#include <linux/uaccess.h>
37+
#include <linux/uio.h>
3738
#include <net/9p/9p.h>
3839
#include <linux/parser.h>
3940
#include <net/9p/client.h>
@@ -555,7 +556,7 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
555556
*/
556557

557558
static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
558-
char *uidata, int in_hdrlen, int kern_buf)
559+
struct iov_iter *uidata, int in_hdrlen)
559560
{
560561
int err;
561562
int ecode;
@@ -591,16 +592,11 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
591592
ename = &req->rc->sdata[req->rc->offset];
592593
if (len > inline_len) {
593594
/* We have error in external buffer */
594-
if (kern_buf) {
595-
memcpy(ename + inline_len, uidata,
596-
len - inline_len);
597-
} else {
598-
err = copy_from_user(ename + inline_len,
599-
uidata, len - inline_len);
600-
if (err) {
601-
err = -EFAULT;
602-
goto out_err;
603-
}
595+
err = copy_from_iter(ename + inline_len,
596+
len - inline_len, uidata);
597+
if (err != len - inline_len) {
598+
err = -EFAULT;
599+
goto out_err;
604600
}
605601
}
606602
ename = NULL;
@@ -806,8 +802,8 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
806802
* p9_client_zc_rpc - issue a request and wait for a response
807803
* @c: client session
808804
* @type: type of request
809-
* @uidata: user bffer that should be ued for zero copy read
810-
* @uodata: user buffer that shoud be user for zero copy write
805+
* @uidata: destination for zero copy read
806+
* @uodata: source for zero copy write
811807
* @inlen: read buffer size
812808
* @olen: write buffer size
813809
* @hdrlen: reader header size, This is the size of response protocol data
@@ -816,9 +812,10 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
816812
* Returns request structure (which client must free using p9_free_req)
817813
*/
818814
static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
819-
char *uidata, char *uodata,
815+
struct iov_iter *uidata,
816+
struct iov_iter *uodata,
820817
int inlen, int olen, int in_hdrlen,
821-
int kern_buf, const char *fmt, ...)
818+
const char *fmt, ...)
822819
{
823820
va_list ap;
824821
int sigpending, err;
@@ -841,12 +838,8 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
841838
} else
842839
sigpending = 0;
843840

844-
/* If we are called with KERNEL_DS force kern_buf */
845-
if (segment_eq(get_fs(), KERNEL_DS))
846-
kern_buf = 1;
847-
848841
err = c->trans_mod->zc_request(c, req, uidata, uodata,
849-
inlen, olen, in_hdrlen, kern_buf);
842+
inlen, olen, in_hdrlen);
850843
if (err < 0) {
851844
if (err == -EIO)
852845
c->status = Disconnected;
@@ -876,7 +869,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
876869
if (err < 0)
877870
goto reterr;
878871

879-
err = p9_check_zc_errors(c, req, uidata, in_hdrlen, kern_buf);
872+
err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
880873
trace_9p_client_res(c, type, req->rc->tag, err);
881874
if (!err)
882875
return req;
@@ -1545,11 +1538,24 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
15451538
u32 count)
15461539
{
15471540
char *dataptr;
1548-
int kernel_buf = 0;
15491541
struct p9_req_t *req;
15501542
struct p9_client *clnt;
15511543
int err, rsize, non_zc = 0;
1552-
1544+
struct iov_iter to;
1545+
union {
1546+
struct kvec kv;
1547+
struct iovec iov;
1548+
} v;
1549+
1550+
if (data) {
1551+
v.kv.iov_base = data;
1552+
v.kv.iov_len = count;
1553+
iov_iter_kvec(&to, ITER_KVEC | READ, &v.kv, 1, count);
1554+
} else {
1555+
v.iov.iov_base = udata;
1556+
v.iov.iov_len = count;
1557+
iov_iter_init(&to, READ, &v.iov, 1, count);
1558+
}
15531559

15541560
p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
15551561
fid->fid, (unsigned long long) offset, count);
@@ -1565,18 +1571,12 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
15651571

15661572
/* Don't bother zerocopy for small IO (< 1024) */
15671573
if (clnt->trans_mod->zc_request && rsize > 1024) {
1568-
char *indata;
1569-
if (data) {
1570-
kernel_buf = 1;
1571-
indata = data;
1572-
} else
1573-
indata = (__force char *)udata;
15741574
/*
15751575
* response header len is 11
15761576
* PDU Header(7) + IO Size (4)
15771577
*/
1578-
req = p9_client_zc_rpc(clnt, P9_TREAD, indata, NULL, rsize, 0,
1579-
11, kernel_buf, "dqd", fid->fid,
1578+
req = p9_client_zc_rpc(clnt, P9_TREAD, &to, NULL, rsize, 0,
1579+
11, "dqd", fid->fid,
15801580
offset, rsize);
15811581
} else {
15821582
non_zc = 1;
@@ -1596,16 +1596,9 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
15961596

15971597
p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
15981598

1599-
if (non_zc) {
1600-
if (data) {
1601-
memmove(data, dataptr, count);
1602-
} else {
1603-
err = copy_to_user(udata, dataptr, count);
1604-
if (err) {
1605-
err = -EFAULT;
1606-
goto free_and_error;
1607-
}
1608-
}
1599+
if (non_zc && copy_to_iter(dataptr, count, &to) != count) {
1600+
err = -EFAULT;
1601+
goto free_and_error;
16091602
}
16101603
p9_free_req(clnt, req);
16111604
return count;
@@ -1622,9 +1615,23 @@ p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
16221615
u64 offset, u32 count)
16231616
{
16241617
int err, rsize;
1625-
int kernel_buf = 0;
16261618
struct p9_client *clnt;
16271619
struct p9_req_t *req;
1620+
struct iov_iter from;
1621+
union {
1622+
struct kvec kv;
1623+
struct iovec iov;
1624+
} v;
1625+
1626+
if (data) {
1627+
v.kv.iov_base = data;
1628+
v.kv.iov_len = count;
1629+
iov_iter_kvec(&from, ITER_KVEC | WRITE, &v.kv, 1, count);
1630+
} else {
1631+
v.iov.iov_base = udata;
1632+
v.iov.iov_len = count;
1633+
iov_iter_init(&from, WRITE, &v.iov, 1, count);
1634+
}
16281635

16291636
p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
16301637
fid->fid, (unsigned long long) offset, count);
@@ -1640,22 +1647,12 @@ p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
16401647

16411648
/* Don't bother zerocopy for small IO (< 1024) */
16421649
if (clnt->trans_mod->zc_request && rsize > 1024) {
1643-
char *odata;
1644-
if (data) {
1645-
kernel_buf = 1;
1646-
odata = data;
1647-
} else
1648-
odata = (char *)udata;
1649-
req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, odata, 0, rsize,
1650-
P9_ZC_HDR_SZ, kernel_buf, "dqd",
1650+
req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &from, 0, rsize,
1651+
P9_ZC_HDR_SZ, "dqd",
16511652
fid->fid, offset, rsize);
16521653
} else {
1653-
if (data)
1654-
req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid,
1655-
offset, rsize, data);
1656-
else
1657-
req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid,
1658-
offset, rsize, udata);
1654+
req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
1655+
offset, rsize, &from);
16591656
}
16601657
if (IS_ERR(req)) {
16611658
err = PTR_ERR(req);
@@ -2068,6 +2065,10 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
20682065
struct p9_client *clnt;
20692066
struct p9_req_t *req;
20702067
char *dataptr;
2068+
struct kvec kv = {.iov_base = data, .iov_len = count};
2069+
struct iov_iter to;
2070+
2071+
iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
20712072

20722073
p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
20732074
fid->fid, (unsigned long long) offset, count);
@@ -2088,8 +2089,8 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
20882089
* response header len is 11
20892090
* PDU Header(7) + IO Size (4)
20902091
*/
2091-
req = p9_client_zc_rpc(clnt, P9_TREADDIR, data, NULL, rsize, 0,
2092-
11, 1, "dqd", fid->fid, offset, rsize);
2092+
req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
2093+
11, "dqd", fid->fid, offset, rsize);
20932094
} else {
20942095
non_zc = 1;
20952096
req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,

‎net/9p/protocol.c

Lines changed: 8 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -33,6 +33,7 @@
3333
#include <linux/sched.h>
3434
#include <linux/stddef.h>
3535
#include <linux/types.h>
36+
#include <linux/uio.h>
3637
#include <net/9p/9p.h>
3738
#include <net/9p/client.h>
3839
#include "protocol.h"
@@ -69,10 +70,11 @@ static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
6970
}
7071

7172
static size_t
72-
pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
73+
pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
7374
{
7475
size_t len = min(pdu->capacity - pdu->size, size);
75-
if (copy_from_user(&pdu->sdata[pdu->size], udata, len))
76+
struct iov_iter i = *from;
77+
if (copy_from_iter(&pdu->sdata[pdu->size], len, &i) != len)
7678
len = 0;
7779

7880
pdu->size += len;
@@ -437,23 +439,13 @@ p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
437439
stbuf->extension, stbuf->n_uid,
438440
stbuf->n_gid, stbuf->n_muid);
439441
} break;
440-
case 'D':{
441-
uint32_t count = va_arg(ap, uint32_t);
442-
const void *data = va_arg(ap, const void *);
443-
444-
errcode = p9pdu_writef(pdu, proto_version, "d",
445-
count);
446-
if (!errcode && pdu_write(pdu, data, count))
447-
errcode = -EFAULT;
448-
}
449-
break;
450-
case 'U':{
442+
case 'V':{
451443
int32_t count = va_arg(ap, int32_t);
452-
const char __user *udata =
453-
va_arg(ap, const void __user *);
444+
struct iov_iter *from =
445+
va_arg(ap, struct iov_iter *);
454446
errcode = p9pdu_writef(pdu, proto_version, "d",
455447
count);
456-
if (!errcode && pdu_write_u(pdu, udata, count))
448+
if (!errcode && pdu_write_u(pdu, from, count))
457449
errcode = -EFAULT;
458450
}
459451
break;

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