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authorAl Viro <viro@zeniv.linux.org.uk>2015-04-01 19:57:53 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2015-04-11 22:28:25 -0400
commit4f3b35c157e43107cc7e1f1aa06694e8b22e10bb (patch)
tree2e871c8698529878f93c225b818f4aa4b871f3c6 /net/9p
parent6e242a1ceeb1bcf55ffefa84d3079f711fe8a667 (diff)
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>
Diffstat (limited to 'net/9p')
-rw-r--r--net/9p/client.c117
-rw-r--r--net/9p/protocol.c24
-rw-r--r--net/9p/trans_virtio.c137
3 files changed, 146 insertions, 132 deletions
diff --git a/net/9p/client.c b/net/9p/client.c
index e86a9bea1d16..9ef5d85f082f 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -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,
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index ab9127ec5b7a..e9d0f0c1a048 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -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;
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 36a1a739ad68..e62bcbbabb5e 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -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);
+ 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);
+ }
+ 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(data);
- data += s;
- nr_pages--;
+ (*pages)[index] = kmap_to_page(p);
+ p += PAGE_SIZE;
}
- nr_pages = count;
+ 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;
- }
- 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;
+ 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;
}
- }
- 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);