redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

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>
hifive-unleashed-5.1
Al Viro 2015-04-01 19:57:53 -04:00
parent 6e242a1cee
commit 4f3b35c157
4 changed files with 147 additions and 133 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/9p/transport.h
View File

@ -61,7 +61,7 @@ struct p9_trans_module {
int (*cancel) (struct p9_client *, struct p9_req_t *req);
int (*cancelled)(struct p9_client *, struct p9_req_t *req);
int (*zc_request)(struct p9_client *, struct p9_req_t *,
char *, char *, int , int, int, int);
struct iov_iter *, struct iov_iter *, int , int, int);
};
void v9fs_register_trans(struct p9_trans_module *m);

115
net/9p/client.c
View File

@ -34,6 +34,7 @@
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/uio.h>
#include <net/9p/9p.h>
#include <linux/parser.h>
#include <net/9p/client.h>
@ -555,7 +556,7 @@ out_err:
*/
static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
char *uidata, int in_hdrlen, int kern_buf)
struct iov_iter *uidata, int in_hdrlen)
{
int err;
int ecode;
@ -591,16 +592,11 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
ename = &req->rc->sdata[req->rc->offset];
if (len > inline_len) {
/* We have error in external buffer */
if (kern_buf) {
memcpy(ename + inline_len, uidata,
len - inline_len);
} else {
err = copy_from_user(ename + inline_len,
uidata, len - inline_len);
if (err) {
err = -EFAULT;
goto out_err;
}
err = copy_from_iter(ename + inline_len,
len - inline_len, uidata);
if (err != len - inline_len) {
err = -EFAULT;
goto out_err;
}
}
ename = NULL;
@ -806,8 +802,8 @@ reterr:
* p9_client_zc_rpc - issue a request and wait for a response
* @c: client session
* @type: type of request
* @uidata: user bffer that should be ued for zero copy read
* @uodata: user buffer that shoud be user for zero copy write
* @uidata: destination for zero copy read
* @uodata: source for zero copy write
* @inlen: read buffer size
* @olen: write buffer size
* @hdrlen: reader header size, This is the size of response protocol data
@ -816,9 +812,10 @@ reterr:
* Returns request structure (which client must free using p9_free_req)
*/
static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
char *uidata, char *uodata,
struct iov_iter *uidata,
struct iov_iter *uodata,
int inlen, int olen, int in_hdrlen,
int kern_buf, const char *fmt, ...)
const char *fmt, ...)
{
va_list ap;
int sigpending, err;
@ -841,12 +838,8 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
} else
sigpending = 0;
/* If we are called with KERNEL_DS force kern_buf */
if (segment_eq(get_fs(), KERNEL_DS))
kern_buf = 1;
err = c->trans_mod->zc_request(c, req, uidata, uodata,
inlen, olen, in_hdrlen, kern_buf);
inlen, olen, in_hdrlen);
if (err < 0) {
if (err == -EIO)
c->status = Disconnected;
@ -876,7 +869,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
if (err < 0)
goto reterr;
err = p9_check_zc_errors(c, req, uidata, in_hdrlen, kern_buf);
err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
trace_9p_client_res(c, type, req->rc->tag, err);
if (!err)
return req;
@ -1545,11 +1538,24 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
u32 count)
{
char *dataptr;
int kernel_buf = 0;
struct p9_req_t *req;
struct p9_client *clnt;
int err, rsize, non_zc = 0;
struct iov_iter to;
union {
struct kvec kv;
struct iovec iov;
} v;
if (data) {
v.kv.iov_base = data;
v.kv.iov_len = count;
iov_iter_kvec(&to, ITER_KVEC | READ, &v.kv, 1, count);
} else {
v.iov.iov_base = udata;
v.iov.iov_len = count;
iov_iter_init(&to, READ, &v.iov, 1, count);
}
p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
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,
/* Don't bother zerocopy for small IO (< 1024) */
if (clnt->trans_mod->zc_request && rsize > 1024) {
char *indata;
if (data) {
kernel_buf = 1;
indata = data;
} else
indata = (__force char *)udata;
/*
* response header len is 11
* PDU Header(7) + IO Size (4)
*/
req = p9_client_zc_rpc(clnt, P9_TREAD, indata, NULL, rsize, 0,
11, kernel_buf, "dqd", fid->fid,
req = p9_client_zc_rpc(clnt, P9_TREAD, &to, NULL, rsize, 0,
11, "dqd", fid->fid,
offset, rsize);
} else {
non_zc = 1;
@ -1596,16 +1596,9 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
if (non_zc) {
if (data) {
memmove(data, dataptr, count);
} else {
err = copy_to_user(udata, dataptr, count);
if (err) {
err = -EFAULT;
goto free_and_error;
}
}
if (non_zc && copy_to_iter(dataptr, count, &to) != count) {
err = -EFAULT;
goto free_and_error;
}
p9_free_req(clnt, req);
return count;
@ -1622,9 +1615,23 @@ p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
u64 offset, u32 count)
{
int err, rsize;
int kernel_buf = 0;
struct p9_client *clnt;
struct p9_req_t *req;
struct iov_iter from;
union {
struct kvec kv;
struct iovec iov;
} v;
if (data) {
v.kv.iov_base = data;
v.kv.iov_len = count;
iov_iter_kvec(&from, ITER_KVEC | WRITE, &v.kv, 1, count);
} else {
v.iov.iov_base = udata;
v.iov.iov_len = count;
iov_iter_init(&from, WRITE, &v.iov, 1, count);
}
p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %d\n",
fid->fid, (unsigned long long) offset, count);
@ -1640,22 +1647,12 @@ p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
/* Don't bother zerocopy for small IO (< 1024) */
if (clnt->trans_mod->zc_request && rsize > 1024) {
char *odata;
if (data) {
kernel_buf = 1;
odata = data;
} else
odata = (char *)udata;
req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, odata, 0, rsize,
P9_ZC_HDR_SZ, kernel_buf, "dqd",
req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &from, 0, rsize,
P9_ZC_HDR_SZ, "dqd",
fid->fid, offset, rsize);
} else {
if (data)
req = p9_client_rpc(clnt, P9_TWRITE, "dqD", fid->fid,
offset, rsize, data);
else
req = p9_client_rpc(clnt, P9_TWRITE, "dqU", fid->fid,
offset, rsize, udata);
req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
offset, rsize, &from);
}
if (IS_ERR(req)) {
err = PTR_ERR(req);
@ -2068,6 +2065,10 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
struct p9_client *clnt;
struct p9_req_t *req;
char *dataptr;
struct kvec kv = {.iov_base = data, .iov_len = count};
struct iov_iter to;
iov_iter_kvec(&to, READ | ITER_KVEC, &kv, 1, count);
p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
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)
* response header len is 11
* PDU Header(7) + IO Size (4)
*/
req = p9_client_zc_rpc(clnt, P9_TREADDIR, data, NULL, rsize, 0,
11, 1, "dqd", fid->fid, offset, rsize);
req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
11, "dqd", fid->fid, offset, rsize);
} else {
non_zc = 1;
req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,

24
net/9p/protocol.c
View File

@ -33,6 +33,7 @@
#include <linux/sched.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/uio.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "protocol.h"
@ -69,10 +70,11 @@ static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
}
static size_t
pdu_write_u(struct p9_fcall *pdu, const char __user *udata, size_t size)
pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
{
size_t len = min(pdu->capacity - pdu->size, size);
if (copy_from_user(&pdu->sdata[pdu->size], udata, len))
struct iov_iter i = *from;
if (copy_from_iter(&pdu->sdata[pdu->size], len, &i) != len)
len = 0;
pdu->size += len;
@ -437,23 +439,13 @@ p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
stbuf->extension, stbuf->n_uid,
stbuf->n_gid, stbuf->n_muid);
} break;
case 'D':{
uint32_t count = va_arg(ap, uint32_t);
const void *data = va_arg(ap, const void *);
errcode = p9pdu_writef(pdu, proto_version, "d",
count);
if (!errcode && pdu_write(pdu, data, count))
errcode = -EFAULT;
}
break;
case 'U':{
case 'V':{
int32_t count = va_arg(ap, int32_t);
const char __user *udata =
va_arg(ap, const void __user *);
struct iov_iter *from =
va_arg(ap, struct iov_iter *);
errcode = p9pdu_writef(pdu, proto_version, "d",
count);
if (!errcode && pdu_write_u(pdu, udata, count))
if (!errcode && pdu_write_u(pdu, from, count))
errcode = -EFAULT;
}
break;

139
net/9p/trans_virtio.c
View File

@ -217,15 +217,15 @@ static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req)
* @start: which segment of the sg_list to start at
* @pdata: a list of pages to add into sg.
* @nr_pages: number of pages to pack into the scatter/gather list
* @data: data to pack into scatter/gather list
* @offs: amount of data in the beginning of first page _not_ to pack
* @count: amount of data to pack into the scatter/gather list
*/
static int
pack_sg_list_p(struct scatterlist *sg, int start, int limit,
struct page **pdata, int nr_pages, char *data, int count)
struct page **pdata, int nr_pages, size_t offs, int count)
{
int i = 0, s;
int data_off;
int data_off = offs;
int index = start;
BUG_ON(nr_pages > (limit - start));
@ -233,16 +233,14 @@ pack_sg_list_p(struct scatterlist *sg, int start, int limit,
* if the first page doesn't start at
* page boundary find the offset
*/
data_off = offset_in_page(data);
while (nr_pages) {
s = rest_of_page(data);
s = PAGE_SIZE - data_off;
if (s > count)
s = count;
/* Make sure we don't terminate early. */
sg_unmark_end(&sg[index]);
sg_set_page(&sg[index++], pdata[i++], s, data_off);
data_off = 0;
data += s;
count -= s;
nr_pages--;
}
@ -314,11 +312,20 @@ req_retry:
}
static int p9_get_mapped_pages(struct virtio_chan *chan,
struct page **pages, char *data,
int nr_pages, int write, int kern_buf)
struct page ***pages,
struct iov_iter *data,
int count,
size_t *offs,
int *need_drop)
{
int nr_pages;
int err;
if (!kern_buf) {
if (!iov_iter_count(data))
return 0;
if (!(data->type & ITER_KVEC)) {
int n;
/*
* We allow only p9_max_pages pinned. We wait for the
* Other zc request to finish here
@ -329,26 +336,49 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
if (err == -ERESTARTSYS)
return err;
}
err = p9_payload_gup(data, &nr_pages, pages, write);
if (err < 0)
return err;
n = iov_iter_get_pages_alloc(data, pages, count, offs);
if (n < 0)
return n;
*need_drop = 1;
nr_pages = DIV_ROUND_UP(n + *offs, PAGE_SIZE);
atomic_add(nr_pages, &vp_pinned);
return n;
} else {
/* kernel buffer, no need to pin pages */
int s, index = 0;
int count = nr_pages;
while (nr_pages) {
s = rest_of_page(data);
if (is_vmalloc_addr(data))
pages[index++] = vmalloc_to_page(data);
else
pages[index++] = kmap_to_page(data);
data += s;
nr_pages--;
int index;
size_t len;
void *p;
/* we'd already checked that it's non-empty */
while (1) {
len = iov_iter_single_seg_count(data);
if (likely(len)) {
p = data->kvec->iov_base + data->iov_offset;
break;
}
iov_iter_advance(data, 0);
}
nr_pages = count;
if (len > count)
len = count;
nr_pages = DIV_ROUND_UP((unsigned long)p + len, PAGE_SIZE) -
(unsigned long)p / PAGE_SIZE;
*pages = kmalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
if (!*pages)
return -ENOMEM;
*need_drop = 0;
p -= (*offs = (unsigned long)p % PAGE_SIZE);
for (index = 0; index < nr_pages; index++) {
if (is_vmalloc_addr(p))
(*pages)[index] = vmalloc_to_page(p);
else
(*pages)[index] = kmap_to_page(p);
p += PAGE_SIZE;
}
return len;
}
return nr_pages;
}
/**
@ -364,8 +394,8 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
*/
static int
p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
char *uidata, char *uodata, int inlen,
int outlen, int in_hdr_len, int kern_buf)
struct iov_iter *uidata, struct iov_iter *uodata,
int inlen, int outlen, int in_hdr_len)
{
int in, out, err, out_sgs, in_sgs;
unsigned long flags;
@ -373,41 +403,32 @@ p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req,
struct page **in_pages = NULL, **out_pages = NULL;
struct virtio_chan *chan = client->trans;
struct scatterlist *sgs[4];
size_t offs;
int need_drop = 0;
p9_debug(P9_DEBUG_TRANS, "virtio request\n");
if (uodata) {
out_nr_pages = p9_nr_pages(uodata, outlen);
out_pages = kmalloc(sizeof(struct page *) * out_nr_pages,
GFP_NOFS);
if (!out_pages) {
err = -ENOMEM;
goto err_out;
int n = p9_get_mapped_pages(chan, &out_pages, uodata,
outlen, &offs, &need_drop);
if (n < 0)
return n;
out_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
if (n != outlen) {
__le32 v = cpu_to_le32(n);
memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4);
outlen = n;
}
out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata,
out_nr_pages, 0, kern_buf);
if (out_nr_pages < 0) {
err = out_nr_pages;
kfree(out_pages);
out_pages = NULL;
goto err_out;
}
}
if (uidata) {
in_nr_pages = p9_nr_pages(uidata, inlen);
in_pages = kmalloc(sizeof(struct page *) * in_nr_pages,
GFP_NOFS);
if (!in_pages) {
err = -ENOMEM;
goto err_out;
}
in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata,
in_nr_pages, 1, kern_buf);
if (in_nr_pages < 0) {
err = in_nr_pages;
kfree(in_pages);
in_pages = NULL;
goto err_out;
} else if (uidata) {
int n = p9_get_mapped_pages(chan, &in_pages, uidata,
inlen, &offs, &need_drop);
if (n < 0)
return n;
in_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE);
if (n != inlen) {
__le32 v = cpu_to_le32(n);
memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4);
inlen = n;
}
}
req->status = REQ_STATUS_SENT;
@ -426,7 +447,7 @@ req_retry_pinned:
if (out_pages) {
sgs[out_sgs++] = chan->sg + out;
out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM,
out_pages, out_nr_pages, uodata, outlen);
out_pages, out_nr_pages, offs, outlen);
}
/*
@ -444,7 +465,7 @@ req_retry_pinned:
if (in_pages) {
sgs[out_sgs + in_sgs++] = chan->sg + out + in;
in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM,
in_pages, in_nr_pages, uidata, inlen);
in_pages, in_nr_pages, offs, inlen);
}
BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs));
@ -478,7 +499,7 @@ req_retry_pinned:
* Non kernel buffers are pinned, unpin them
*/
err_out:
if (!kern_buf) {
if (need_drop) {
if (in_pages) {
p9_release_pages(in_pages, in_nr_pages);
atomic_sub(in_nr_pages, &vp_pinned);