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Message-Id: <1481840034-2113-4-git-send-email-sstabellini@kernel.org>
Date: Thu, 15 Dec 2016 14:13:51 -0800
From: Stefano Stabellini <sstabellini@...nel.org>
To: v9fs-developer@...ts.sourceforge.net
Cc: sstabellini@...nel.org, ericvh@...il.com, rminnich@...dia.gov,
lucho@...kov.net, linux-kernel@...r.kernel.org
Subject: [PATCH v2 4/7] 9p: introduce async read requests
If the read is an async operation, send a 9p request and return
EIOCBQUEUED. Do not wait for completion.
Complete the read operation from a callback instead.
Signed-off-by: Stefano Stabellini <sstabellini@...nel.org>
---
Changes in v2:
- use work_struct to schedule callback
- a few variable renames
- improve the completion function so that it can be called multiple
times on the same request
---
net/9p/client.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 95 insertions(+), 2 deletions(-)
diff --git a/net/9p/client.c b/net/9p/client.c
index 0ff1216..c17596f 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -28,6 +28,7 @@
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
+#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/idr.h>
#include <linux/mutex.h>
@@ -1558,13 +1559,74 @@ int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
}
EXPORT_SYMBOL(p9_client_unlinkat);
+static void
+p9_client_read_complete(struct work_struct *work)
+{
+ struct p9_req_t *req = container_of(work, struct p9_req_t, work);
+ struct p9_client *clnt = req->fid->clnt;
+ uint32_t count = 0, n = 0, total = 0;
+ u64 offset;
+ int err, i;
+ char *dataptr, *to;
+
+ if (req->status == REQ_STATUS_ERROR) {
+ p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
+ err = req->t_err;
+ goto out;
+ }
+ err = p9_check_errors(clnt, req);
+ if (err)
+ goto out;
+
+ err = p9pdu_readf(req->rc, clnt->proto_version,
+ "D", &count, &dataptr);
+ if (err) {
+ trace_9p_protocol_dump(clnt, req->rc);
+ goto out;
+ }
+ if (!count) {
+ p9_debug(P9_DEBUG_ERROR, "count=%d\n", count);
+ err = 0;
+ goto out;
+ }
+
+ p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
+ if (count > req->rsize)
+ count = req->rsize;
+
+ offset = req->page_offset;
+ total = count;
+ for (i = offset / PAGE_SIZE; i < ((total + PAGE_SIZE - 1) / PAGE_SIZE); i++) {
+ to = kmap(req->pagevec[i]);
+ to += offset;
+ n = PAGE_SIZE - offset;
+ if (n > count)
+ n = count;
+ else
+ offset = 0;
+ memcpy(to, dataptr, n);
+ kunmap(req->pagevec[i]);
+ count -= n;
+ }
+
+ err = total;
+ req->kiocb->ki_pos += total;
+
+out:
+ req->kiocb->ki_complete(req->kiocb, err, 0);
+
+ release_pages(req->pagevec, (req->tot_size + PAGE_SIZE - 1) / PAGE_SIZE, false);
+ kvfree(req->pagevec);
+ p9_free_req(clnt, req);
+}
+
int
p9_client_read(struct p9_fid *fid, struct kiocb *iocb, u64 offset,
struct iov_iter *to, int *err)
{
struct p9_client *clnt = fid->clnt;
struct p9_req_t *req;
- int total = 0;
+ int total = 0, i;
*err = 0;
p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n",
@@ -1591,10 +1653,41 @@ int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
0, 11, "dqd", fid->fid,
offset, rsize);
- } else {
+ /* sync request */
+ } else if(iocb == NULL || is_sync_kiocb(iocb)) {
non_zc = 1;
req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
rsize);
+ /* async request */
+ } else {
+ req = p9_client_get_req(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize);
+ if (IS_ERR(req)) {
+ *err = PTR_ERR(req);
+ break;
+ }
+ req->fid = fid;
+ req->file_offset = offset;
+ req->rsize = rsize;
+ req->tot_size = iov_iter_get_pages_alloc(to, &req->pagevec,
+ (size_t)rsize, &req->page_offset);
+ req->kiocb = iocb;
+ for (i = 0; i < req->tot_size; i += PAGE_SIZE)
+ page_cache_get_speculative(req->pagevec[i/PAGE_SIZE]);
+ INIT_WORK(&req->work, p9_client_read_complete);
+
+ *err = clnt->trans_mod->request(clnt, req);
+ if (*err < 0) {
+ clnt->status = Disconnected;
+ release_pages(req->pagevec,
+ (req->tot_size + PAGE_SIZE - 1) / PAGE_SIZE,
+ true);
+ kvfree(req->pagevec);
+ p9_free_req(clnt, req);
+ break;
+ }
+
+ *err = -EIOCBQUEUED;
+ break;
}
if (IS_ERR(req)) {
*err = PTR_ERR(req);
--
1.9.1
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