IB/iser: New receive buffer posting logic
Currently, the recv buffer posting logic is based on the transactional
nature of iSER which allows for posting a buffer before sending a PDU.
Change this to post only when the number of outstanding recv buffers
is below a water mark and in a batched manner, thus simplifying and
optimizing the data path. Use a pre-allocated ring of recv buffers
instead of allocating from kmem cache. A special treatment is given
to the login response buffer whose size must be 8K unlike the size of
buffers used for any other purpose which is 128 bytes.
Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/iser/iser_initiator.c b/drivers/infiniband/ulp/iser/iser_initiator.c
index 5f42fbe..6d9bbe6 100644
--- a/drivers/infiniband/ulp/iser/iser_initiator.c
+++ b/drivers/infiniband/ulp/iser/iser_initiator.c
@@ -39,9 +39,6 @@
#include "iscsi_iser.h"
-/* Constant PDU lengths calculations */
-#define ISER_TOTAL_HEADERS_LEN (sizeof (struct iser_hdr) + \
- sizeof (struct iscsi_hdr))
/* iser_dto_add_regd_buff - increments the reference count for *
* the registered buffer & adds it to the DTO object */
@@ -172,78 +169,6 @@
return 0;
}
-/**
- * iser_post_receive_control - allocates, initializes and posts receive DTO.
- */
-static int iser_post_receive_control(struct iscsi_conn *conn)
-{
- struct iscsi_iser_conn *iser_conn = conn->dd_data;
- struct iser_desc *rx_desc;
- struct iser_regd_buf *regd_hdr;
- struct iser_regd_buf *regd_data;
- struct iser_dto *recv_dto = NULL;
- struct iser_device *device = iser_conn->ib_conn->device;
- int rx_data_size, err = 0;
-
- rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
- if (rx_desc == NULL) {
- iser_err("Failed to alloc desc for post recv\n");
- return -ENOMEM;
- }
- rx_desc->type = ISCSI_RX;
-
- /* for the login sequence we must support rx of upto 8K; login is done
- * after conn create/bind (connect) and conn stop/bind (reconnect),
- * what's common for both schemes is that the connection is not started
- */
- if (conn->c_stage != ISCSI_CONN_STARTED)
- rx_data_size = ISCSI_DEF_MAX_RECV_SEG_LEN;
- else /* FIXME till user space sets conn->max_recv_dlength correctly */
- rx_data_size = 128;
-
- rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
- if (rx_desc->data == NULL) {
- iser_err("Failed to alloc data buf for post recv\n");
- err = -ENOMEM;
- goto post_rx_kmalloc_failure;
- }
-
- recv_dto = &rx_desc->dto;
- recv_dto->ib_conn = iser_conn->ib_conn;
- recv_dto->regd_vector_len = 0;
-
- regd_hdr = &rx_desc->hdr_regd_buf;
- memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
- regd_hdr->device = device;
- regd_hdr->virt_addr = rx_desc; /* == &rx_desc->iser_header */
- regd_hdr->data_size = ISER_TOTAL_HEADERS_LEN;
-
- iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);
-
- iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);
-
- regd_data = &rx_desc->data_regd_buf;
- memset(regd_data, 0, sizeof(struct iser_regd_buf));
- regd_data->device = device;
- regd_data->virt_addr = rx_desc->data;
- regd_data->data_size = rx_data_size;
-
- iser_reg_single(device, regd_data, DMA_FROM_DEVICE);
-
- iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);
-
- err = iser_post_recv(rx_desc);
- if (!err)
- return 0;
-
- /* iser_post_recv failed */
- iser_dto_buffs_release(recv_dto);
- kfree(rx_desc->data);
-post_rx_kmalloc_failure:
- kmem_cache_free(ig.desc_cache, rx_desc);
- return err;
-}
-
/* creates a new tx descriptor and adds header regd buffer */
static void iser_create_send_desc(struct iscsi_iser_conn *iser_conn,
struct iser_desc *tx_desc)
@@ -254,7 +179,7 @@
memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
regd_hdr->device = iser_conn->ib_conn->device;
regd_hdr->virt_addr = tx_desc; /* == &tx_desc->iser_header */
- regd_hdr->data_size = ISER_TOTAL_HEADERS_LEN;
+ regd_hdr->data_size = ISER_HEADERS_LEN;
send_dto->ib_conn = iser_conn->ib_conn;
send_dto->notify_enable = 1;
@@ -266,6 +191,72 @@
iser_dto_add_regd_buff(send_dto, regd_hdr, 0, 0);
}
+int iser_alloc_rx_descriptors(struct iser_conn *ib_conn)
+{
+ int i, j;
+ u64 dma_addr;
+ struct iser_rx_desc *rx_desc;
+ struct ib_sge *rx_sg;
+ struct iser_device *device = ib_conn->device;
+
+ ib_conn->rx_descs = kmalloc(ISER_QP_MAX_RECV_DTOS *
+ sizeof(struct iser_rx_desc), GFP_KERNEL);
+ if (!ib_conn->rx_descs)
+ goto rx_desc_alloc_fail;
+
+ rx_desc = ib_conn->rx_descs;
+
+ for (i = 0; i < ISER_QP_MAX_RECV_DTOS; i++, rx_desc++) {
+ dma_addr = ib_dma_map_single(device->ib_device, (void *)rx_desc,
+ ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
+ if (ib_dma_mapping_error(device->ib_device, dma_addr))
+ goto rx_desc_dma_map_failed;
+
+ rx_desc->dma_addr = dma_addr;
+
+ rx_sg = &rx_desc->rx_sg;
+ rx_sg->addr = rx_desc->dma_addr;
+ rx_sg->length = ISER_RX_PAYLOAD_SIZE;
+ rx_sg->lkey = device->mr->lkey;
+ }
+
+ ib_conn->rx_desc_head = 0;
+ return 0;
+
+rx_desc_dma_map_failed:
+ rx_desc = ib_conn->rx_descs;
+ for (j = 0; j < i; j++, rx_desc++)
+ ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
+ ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
+ kfree(ib_conn->rx_descs);
+ ib_conn->rx_descs = NULL;
+rx_desc_alloc_fail:
+ iser_err("failed allocating rx descriptors / data buffers\n");
+ return -ENOMEM;
+}
+
+void iser_free_rx_descriptors(struct iser_conn *ib_conn)
+{
+ int i;
+ struct iser_rx_desc *rx_desc;
+ struct iser_device *device = ib_conn->device;
+
+ if (ib_conn->login_buf) {
+ ib_dma_unmap_single(device->ib_device, ib_conn->login_dma,
+ ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
+ kfree(ib_conn->login_buf);
+ }
+
+ if (!ib_conn->rx_descs)
+ return;
+
+ rx_desc = ib_conn->rx_descs;
+ for (i = 0; i < ISER_QP_MAX_RECV_DTOS; i++, rx_desc++)
+ ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
+ ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
+ kfree(ib_conn->rx_descs);
+}
+
/**
* iser_conn_set_full_featured_mode - (iSER API)
*/
@@ -273,27 +264,20 @@
{
struct iscsi_iser_conn *iser_conn = conn->dd_data;
- int i;
- /* no need to keep it in a var, we are after login so if this should
- * be negotiated, by now the result should be available here */
- int initial_post_recv_bufs_num = ISER_MAX_RX_MISC_PDUS;
-
- iser_dbg("Initially post: %d\n", initial_post_recv_bufs_num);
+ iser_dbg("Initially post: %d\n", ISER_MIN_POSTED_RX);
/* Check that there is no posted recv or send buffers left - */
/* they must be consumed during the login phase */
BUG_ON(atomic_read(&iser_conn->ib_conn->post_recv_buf_count) != 0);
BUG_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
+ if (iser_alloc_rx_descriptors(iser_conn->ib_conn))
+ return -ENOMEM;
+
/* Initial post receive buffers */
- for (i = 0; i < initial_post_recv_bufs_num; i++) {
- if (iser_post_receive_control(conn) != 0) {
- iser_err("Failed to post recv bufs at:%d conn:0x%p\n",
- i, conn);
- return -ENOMEM;
- }
- }
- iser_dbg("Posted %d post recv bufs, conn:0x%p\n", i, conn);
+ if (iser_post_recvm(iser_conn->ib_conn, ISER_MIN_POSTED_RX))
+ return -ENOMEM;
+
return 0;
}
@@ -321,7 +305,7 @@
struct iscsi_iser_task *iser_task = task->dd_data;
struct iser_dto *send_dto = NULL;
unsigned long edtl;
- int err = 0;
+ int err;
struct iser_data_buf *data_buf;
struct iscsi_cmd *hdr = (struct iscsi_cmd *)task->hdr;
struct scsi_cmnd *sc = task->sc;
@@ -371,12 +355,6 @@
iser_reg_single(iser_conn->ib_conn->device,
send_dto->regd[0], DMA_TO_DEVICE);
- if (iser_post_receive_control(conn) != 0) {
- iser_err("post_recv failed!\n");
- err = -ENOMEM;
- goto send_command_error;
- }
-
iser_task->status = ISER_TASK_STATUS_STARTED;
err = iser_post_send(&iser_task->desc);
@@ -474,7 +452,7 @@
struct iser_desc *mdesc = &iser_task->desc;
struct iser_dto *send_dto = NULL;
unsigned long data_seg_len;
- int err = 0;
+ int err;
struct iser_regd_buf *regd_buf;
struct iser_device *device;
@@ -511,10 +489,10 @@
data_seg_len);
}
- if (iser_post_receive_control(conn) != 0) {
- iser_err("post_rcv_buff failed!\n");
- err = -ENOMEM;
- goto send_control_error;
+ if (task == conn->login_task) {
+ err = iser_post_recvl(iser_conn->ib_conn);
+ if (err)
+ goto send_control_error;
}
err = iser_post_send(mdesc);
@@ -530,27 +508,34 @@
/**
* iser_rcv_dto_completion - recv DTO completion
*/
-void iser_rcv_completion(struct iser_desc *rx_desc,
- unsigned long dto_xfer_len)
+void iser_rcv_completion(struct iser_rx_desc *rx_desc,
+ unsigned long rx_xfer_len,
+ struct iser_conn *ib_conn)
{
- struct iser_dto *dto = &rx_desc->dto;
- struct iscsi_iser_conn *conn = dto->ib_conn->iser_conn;
+ struct iscsi_iser_conn *conn = ib_conn->iser_conn;
struct iscsi_task *task;
struct iscsi_iser_task *iser_task;
struct iscsi_hdr *hdr;
- char *rx_data = NULL;
- int rx_data_len = 0;
unsigned char opcode;
+ u64 rx_dma;
+ int rx_buflen, outstanding, count, err;
+
+ /* differentiate between login to all other PDUs */
+ if ((char *)rx_desc == ib_conn->login_buf) {
+ rx_dma = ib_conn->login_dma;
+ rx_buflen = ISER_RX_LOGIN_SIZE;
+ } else {
+ rx_dma = rx_desc->dma_addr;
+ rx_buflen = ISER_RX_PAYLOAD_SIZE;
+ }
+
+ ib_dma_sync_single_for_cpu(ib_conn->device->ib_device, rx_dma,
+ rx_buflen, DMA_FROM_DEVICE);
hdr = &rx_desc->iscsi_header;
- iser_dbg("op 0x%x itt 0x%x\n", hdr->opcode,hdr->itt);
-
- if (dto_xfer_len > ISER_TOTAL_HEADERS_LEN) { /* we have data */
- rx_data_len = dto_xfer_len - ISER_TOTAL_HEADERS_LEN;
- rx_data = dto->regd[1]->virt_addr;
- rx_data += dto->offset[1];
- }
+ iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,
+ hdr->itt, (int)(rx_xfer_len - ISER_HEADERS_LEN));
opcode = hdr->opcode & ISCSI_OPCODE_MASK;
@@ -573,18 +558,30 @@
iscsi_put_task(task);
}
}
- iser_dto_buffs_release(dto);
- iscsi_iser_recv(conn->iscsi_conn, hdr, rx_data, rx_data_len);
+ iscsi_iser_recv(conn->iscsi_conn, hdr,
+ rx_desc->data, rx_xfer_len - ISER_HEADERS_LEN);
- kfree(rx_desc->data);
- kmem_cache_free(ig.desc_cache, rx_desc);
+ ib_dma_sync_single_for_device(ib_conn->device->ib_device, rx_dma,
+ rx_buflen, DMA_FROM_DEVICE);
/* decrementing conn->post_recv_buf_count only --after-- freeing the *
* task eliminates the need to worry on tasks which are completed in *
* parallel to the execution of iser_conn_term. So the code that waits *
* for the posted rx bufs refcount to become zero handles everything */
atomic_dec(&conn->ib_conn->post_recv_buf_count);
+
+ if (rx_dma == ib_conn->login_dma)
+ return;
+
+ outstanding = atomic_read(&ib_conn->post_recv_buf_count);
+ if (outstanding + ISER_MIN_POSTED_RX <= ISER_QP_MAX_RECV_DTOS) {
+ count = min(ISER_QP_MAX_RECV_DTOS - outstanding,
+ ISER_MIN_POSTED_RX);
+ err = iser_post_recvm(ib_conn, count);
+ if (err)
+ iser_err("posting %d rx bufs err %d\n", count, err);
+ }
}
void iser_snd_completion(struct iser_desc *tx_desc)