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Date: Wed, 2 Aug 2017 13:10:32 -0700
From: Long Li <longli@...hange.microsoft.com>
To: Steve French <sfrench@...ba.org>, linux-cifs@...r.kernel.org,
samba-technical@...ts.samba.org, linux-kernel@...r.kernel.org
Cc: Long Li <longli@...rosoft.com>
Subject: [[PATCH v1] 21/37] [CIFS] SMBD: Implement API for upper layer to receive data
From: Long Li <longli@...rosoft.com>
With reassembly queue in place, implement the API for upper layer to recevie data. This call may sleep if there is not enough data in the reassembly queue.
Signed-off-by: Long Li <longli@...rosoft.com>
---
fs/cifs/cifsrdma.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/cifs/cifsrdma.h | 5 +++
2 files changed, 115 insertions(+)
diff --git a/fs/cifs/cifsrdma.c b/fs/cifs/cifsrdma.c
index 1d3fd26..e5f6300 100644
--- a/fs/cifs/cifsrdma.c
+++ b/fs/cifs/cifsrdma.c
@@ -1316,6 +1316,116 @@ struct cifs_rdma_info* cifs_create_rdma_session(
}
/*
+ * Read data from receive reassembly queue
+ * All the incoming data packets are placed in reassembly queue
+ * buf: the buffer to read data into
+ * size: the length of data to read
+ * return value: actual data read
+ */
+int cifs_rdma_read(struct cifs_rdma_info *info, char *buf, unsigned int size)
+{
+ struct cifs_rdma_response *response;
+ struct smbd_data_transfer *data_transfer;
+ unsigned long flags;
+ int to_copy, to_read, data_read, offset;
+ u32 data_length, remaining_data_length, data_offset;
+
+again:
+ // the transport is disconnected?
+ if (info->transport_status != CIFS_RDMA_CONNECTED) {
+ log_cifs_read("disconnected\n");
+
+ /*
+ * If upper layer code is reading SMB packet length
+ * return 0 to indicate transport is disconnected and
+ * trigger a reconnect.
+ */
+ spin_lock_irqsave(&info->reassembly_queue_lock, flags);
+ response = _get_first_reassembly(info);
+ if (response && response->first_segment && size==4) {
+ memset(buf, 0, size);
+ spin_unlock_irqrestore(&info->reassembly_queue_lock, flags);
+ return size;
+ }
+ spin_unlock_irqrestore(&info->reassembly_queue_lock, flags);
+ return 0;
+ }
+
+ spin_lock_irqsave(&info->reassembly_queue_lock, flags);
+ log_cifs_read("size=%d info->reassembly_data_length=%d\n", size,
+ atomic_read(&info->reassembly_data_length));
+ if (atomic_read(&info->reassembly_data_length) >= size) {
+ data_read = 0;
+ to_read = size;
+ offset = info->first_entry_offset;
+ while(data_read < size) {
+ response = _get_first_reassembly(info);
+ data_transfer = (struct smbd_data_transfer *) response->packet;
+
+ data_length = le32_to_cpu(data_transfer->data_length);
+ remaining_data_length =
+ le32_to_cpu(data_transfer->remaining_data_length);
+ data_offset = le32_to_cpu(data_transfer->data_offset);
+
+ // this is for reading rfc1002 length
+ if (response->first_segment && size==4) {
+ unsigned int rfc1002_len =
+ data_length + remaining_data_length;
+ *((__be32*)buf) = cpu_to_be32(rfc1002_len);
+ data_read = 4;
+ response->first_segment = false;
+ log_cifs_read("returning rfc1002 length %d\n",
+ rfc1002_len);
+ goto read_rfc1002_done;
+ }
+
+ to_copy = min_t(int, data_length - offset, to_read);
+ memcpy(
+ buf + data_read,
+ (char*)data_transfer + data_offset + offset,
+ to_copy);
+
+ // move on to the next buffer?
+ if (to_copy == data_length - offset) {
+ list_del(&response->list);
+ info->count_reassembly_queue--;
+ info->count_dequeue_reassembly_queue++;
+ put_receive_buffer(info, response);
+ offset = 0;
+ log_cifs_read("put_receive_buffer offset=0\n");
+ } else
+ offset += to_copy;
+
+ to_read -= to_copy;
+ data_read += to_copy;
+
+ log_cifs_read("_get_first_reassembly memcpy %d bytes "
+ "data_transfer_length-offset=%d after that "
+ "to_read=%d data_read=%d offset=%d\n",
+ to_copy, data_length - offset,
+ to_read, data_read, offset);
+ }
+ atomic_sub(data_read, &info->reassembly_data_length);
+ info->first_entry_offset = offset;
+ log_cifs_read("returning to thread data_read=%d "
+ "reassembly_data_length=%d first_entry_offset=%d\n",
+ data_read, atomic_read(&info->reassembly_data_length),
+ info->first_entry_offset);
+read_rfc1002_done:
+ spin_unlock_irqrestore(&info->reassembly_queue_lock, flags);
+ return data_read;
+ }
+
+ spin_unlock_irqrestore(&info->reassembly_queue_lock, flags);
+ log_cifs_read("wait_event on more data\n");
+ wait_event(
+ info->wait_reassembly_queue,
+ atomic_read(&info->reassembly_data_length) >= size ||
+ info->transport_status != CIFS_RDMA_CONNECTED);
+ goto again;
+}
+
+/*
* Write data to transport
* Each rqst is transported as a SMBDirect payload
* rqst: the data to write
diff --git a/fs/cifs/cifsrdma.h b/fs/cifs/cifsrdma.h
index b26e3b7..8891e21 100644
--- a/fs/cifs/cifsrdma.h
+++ b/fs/cifs/cifsrdma.h
@@ -89,6 +89,8 @@ struct cifs_rdma_info {
// total data length of reassembly queue
atomic_t reassembly_data_length;
+ // the offset to first buffer in reassembly queue
+ int first_entry_offset;
wait_queue_head_t wait_send_queue;
@@ -210,5 +212,8 @@ struct cifs_rdma_response {
struct cifs_rdma_info* cifs_create_rdma_session(
struct TCP_Server_Info *server, struct sockaddr *dstaddr);
+// SMBDirect interface for carrying upper layer CIFS I/O
+int cifs_rdma_read(
+ struct cifs_rdma_info *rdma, char *buf, unsigned int to_read);
int cifs_rdma_write(struct cifs_rdma_info *rdma, struct smb_rqst *rqst);
#endif
--
2.7.4
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