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Date: Wed, 5 Feb 2020 03:34:56 +0300
From: Sergey Alirzaev <l29ah@...k.li>
To: v9fs-developer@...ts.sourceforge.net
Cc: Eric Van Hensbergen <ericvh@...il.com>,
Latchesar Ionkov <lucho@...kov.net>,
Dominique Martinet <asmadeus@...ewreck.org>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Sergey Alirzaev <l29ah@...k.li>
Subject: [PATCH 1/2] 9pnet: allow making incomplete read requests
A user doesn't necessarily want to wait for all the requested data to
be available, since the waiting time is unbounded.
Signed-off-by: Sergey Alirzaev <l29ah@...k.li>
---
include/net/9p/client.h | 2 +
net/9p/client.c | 133 ++++++++++++++++++++++------------------
2 files changed, 76 insertions(+), 59 deletions(-)
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index acc60d8a3b3b..f6c890e94f87 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -200,6 +200,8 @@ int p9_client_fsync(struct p9_fid *fid, int datasync);
int p9_client_remove(struct p9_fid *fid);
int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags);
int p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err);
+int p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
+ int *err);
int p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err);
int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
int p9dirent_read(struct p9_client *clnt, char *buf, int len,
diff --git a/net/9p/client.c b/net/9p/client.c
index 1d48afc7033c..186f5b44aa01 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -1548,83 +1548,98 @@ EXPORT_SYMBOL(p9_client_unlinkat);
int
p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
+{
+ int total = 0;
+ *err = 0;
+
+ while (iov_iter_count(to)) {
+ int count;
+
+ count = p9_client_read_once(fid, offset, to, err);
+ if (!count || *err)
+ break;
+ offset += count;
+ total += count;
+ }
+ return total;
+}
+EXPORT_SYMBOL(p9_client_read);
+
+int
+p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
+ int *err)
{
struct p9_client *clnt = fid->clnt;
struct p9_req_t *req;
int total = 0;
- *err = 0;
+ int count = iov_iter_count(to);
+ int rsize, non_zc = 0;
+ char *dataptr;
+ *err = 0;
p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
fid->fid, (unsigned long long) offset, (int)iov_iter_count(to));
- while (iov_iter_count(to)) {
- int count = iov_iter_count(to);
- int rsize, non_zc = 0;
- char *dataptr;
+ rsize = fid->iounit;
+ if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
+ rsize = clnt->msize - P9_IOHDRSZ;
- rsize = fid->iounit;
- if (!rsize || rsize > clnt->msize-P9_IOHDRSZ)
- rsize = clnt->msize - P9_IOHDRSZ;
+ if (count < rsize)
+ rsize = count;
- if (count < rsize)
- rsize = count;
+ /* Don't bother zerocopy for small IO (< 1024) */
+ if (clnt->trans_mod->zc_request && rsize > 1024) {
+ /* response header len is 11
+ * PDU Header(7) + IO Size (4)
+ */
+ req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
+ 0, 11, "dqd", fid->fid,
+ offset, rsize);
+ } else {
+ non_zc = 1;
+ req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
+ rsize);
+ }
+ if (IS_ERR(req)) {
+ *err = PTR_ERR(req);
+ return total;
+ }
- /* Don't bother zerocopy for small IO (< 1024) */
- if (clnt->trans_mod->zc_request && rsize > 1024) {
- /*
- * response header len is 11
- * PDU Header(7) + IO Size (4)
- */
- req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
- 0, 11, "dqd", fid->fid,
- offset, rsize);
- } else {
- non_zc = 1;
- req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
- rsize);
- }
- if (IS_ERR(req)) {
- *err = PTR_ERR(req);
- break;
- }
+ *err = p9pdu_readf(&req->rc, clnt->proto_version,
+ "D", &count, &dataptr);
+ if (*err) {
+ trace_9p_protocol_dump(clnt, &req->rc);
+ p9_tag_remove(clnt, req);
+ return total;
+ }
+ if (rsize < count) {
+ pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
+ count = rsize;
+ }
- *err = p9pdu_readf(&req->rc, clnt->proto_version,
- "D", &count, &dataptr);
- if (*err) {
- trace_9p_protocol_dump(clnt, &req->rc);
- p9_tag_remove(clnt, req);
- break;
- }
- if (rsize < count) {
- pr_err("bogus RREAD count (%d > %d)\n", count, rsize);
- count = rsize;
- }
+ p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
+ if (!count) {
+ p9_tag_remove(clnt, req);
+ return total;
+ }
- p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
- if (!count) {
- p9_tag_remove(clnt, req);
- break;
- }
+ if (non_zc) {
+ int n = copy_to_iter(dataptr, count, to);
- if (non_zc) {
- int n = copy_to_iter(dataptr, count, to);
- total += n;
- offset += n;
- if (n != count) {
- *err = -EFAULT;
- p9_tag_remove(clnt, req);
- break;
- }
- } else {
- iov_iter_advance(to, count);
- total += count;
- offset += count;
+ total += n;
+ if (n != count) {
+ *err = -EFAULT;
+ p9_tag_remove(clnt, req);
+ return total;
}
- p9_tag_remove(clnt, req);
+ } else {
+ iov_iter_advance(to, count);
+ total += count;
}
+ p9_tag_remove(clnt, req);
return total;
}
-EXPORT_SYMBOL(p9_client_read);
+EXPORT_SYMBOL(p9_client_read_once);
int
p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
--
2.25.0
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