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Subject[[PATCH v1] 07/37] [CIFS] SMBD: Implement receive buffer for handling SMBD response
Date
From: Long Li <longli@microsoft.com>

Create recevie buffers to handling SMBD response messages. Each SMBD response message is assocated with a receive buffer, where the message payload is received. The number of receive buffer is determine after negotiating SMBD transport with the server.

Signed-off-by: Long Li <longli@microsoft.com>
---
fs/cifs/cifsrdma.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/cifs/cifsrdma.h | 3 ++
2 files changed, 92 insertions(+)

diff --git a/fs/cifs/cifsrdma.c b/fs/cifs/cifsrdma.c
index 1636304..b3e43b1 100644
--- a/fs/cifs/cifsrdma.c
+++ b/fs/cifs/cifsrdma.c
@@ -54,6 +54,14 @@

#include "cifsrdma.h"

+static struct cifs_rdma_response* get_receive_buffer(
+ struct cifs_rdma_info *info);
+static void put_receive_buffer(
+ struct cifs_rdma_info *info,
+ struct cifs_rdma_response *response);
+static int allocate_receive_buffers(struct cifs_rdma_info *info, int num_buf);
+static void destroy_receive_buffers(struct cifs_rdma_info *info);
+
/*
* Per RDMA transport connection parameters
* as defined in [MS-SMBD] 3.1.1.1
@@ -280,6 +288,85 @@ static int cifs_rdma_ia_open(
return rc;
}

+/*
+ * Receive buffer operations.
+ * For each remote send, we need to post a receive. The receive buffers are
+ * pre-allocated in advance.
+ */
+static struct cifs_rdma_response* get_receive_buffer(struct cifs_rdma_info *info)
+{
+ struct cifs_rdma_response *ret = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&info->receive_queue_lock, flags);
+ if (!list_empty(&info->receive_queue)) {
+ ret = list_first_entry(
+ &info->receive_queue,
+ struct cifs_rdma_response, list);
+ list_del(&ret->list);
+ info->count_receive_buffer--;
+ info->count_get_receive_buffer++;
+ }
+ spin_unlock_irqrestore(&info->receive_queue_lock, flags);
+
+ return ret;
+}
+
+static void put_receive_buffer(
+ struct cifs_rdma_info *info, struct cifs_rdma_response *response)
+{
+ unsigned long flags;
+
+ ib_dma_unmap_single(info->id->device, response->sge.addr,
+ response->sge.length, DMA_FROM_DEVICE);
+
+ spin_lock_irqsave(&info->receive_queue_lock, flags);
+ list_add_tail(&response->list, &info->receive_queue);
+ info->count_receive_buffer++;
+ info->count_put_receive_buffer++;
+ spin_unlock_irqrestore(&info->receive_queue_lock, flags);
+}
+
+static int allocate_receive_buffers(struct cifs_rdma_info *info, int num_buf)
+{
+ int i;
+ struct cifs_rdma_response *response;
+
+ INIT_LIST_HEAD(&info->receive_queue);
+ spin_lock_init(&info->receive_queue_lock);
+
+ for (i=0; i<num_buf; i++) {
+ response = mempool_alloc(info->response_mempool, GFP_KERNEL);
+ if (!response)
+ goto allocate_failed;
+
+ response->info = info;
+ list_add_tail(&response->list, &info->receive_queue);
+ info->count_receive_buffer++;
+ }
+
+ return 0;
+
+allocate_failed:
+ while (!list_empty(&info->receive_queue)) {
+ response = list_first_entry(
+ &info->receive_queue,
+ struct cifs_rdma_response, list);
+ list_del(&response->list);
+ info->count_receive_buffer--;
+
+ mempool_free(response, info->response_mempool);
+ }
+ return -ENOMEM;
+}
+
+static void destroy_receive_buffers(struct cifs_rdma_info *info)
+{
+ struct cifs_rdma_response *response;
+ while ((response = get_receive_buffer(info)))
+ mempool_free(response, info->response_mempool);
+}
+
struct cifs_rdma_info* cifs_create_rdma_session(
struct TCP_Server_Info *server, struct sockaddr *dstaddr)
{
@@ -383,6 +470,8 @@ struct cifs_rdma_info* cifs_create_rdma_session(
info->response_mempool =
mempool_create(info->receive_credit_max, mempool_alloc_slab,
mempool_free_slab, info->response_cache);
+
+ allocate_receive_buffers(info, info->receive_credit_max);
out2:
rdma_destroy_id(info->id);

diff --git a/fs/cifs/cifsrdma.h b/fs/cifs/cifsrdma.h
index 41ae61a..78ce2bf 100644
--- a/fs/cifs/cifsrdma.h
+++ b/fs/cifs/cifsrdma.h
@@ -59,6 +59,9 @@ struct cifs_rdma_info {
atomic_t receive_credits;
atomic_t receive_credit_target;

+ struct list_head receive_queue;
+ spinlock_t receive_queue_lock;
+
// response pool for RDMA receive
struct kmem_cache *response_cache;
mempool_t *response_mempool;
--
2.7.4
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