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authorLong Li <longli@microsoft.com>2017-11-22 17:38:47 -0700
committerSteve French <smfrench@gmail.com>2018-01-24 19:49:07 -0600
commitbd3dcc6a22a9186ed78da51ce09e889803552189 (patch)
treef334b0f07c9789530c971464426ac6208ec2582d /fs
parent74dcf418fe344657b0e48a5a4b75f935443fa53f (diff)
CIFS: SMBD: Upper layer performs SMB read via RDMA write through memory registration
If I/O size is larger than rdma_readwrite_threshold, use RDMA write for SMB read by specifying channel SMB2_CHANNEL_RDMA_V1 or SMB2_CHANNEL_RDMA_V1_INVALIDATE in the SMB packet, depending on SMB dialect used. Append a smbd_buffer_descriptor_v1 to the end of the SMB packet and fill in other values to indicate this SMB read uses RDMA write. There is no need to read from the transport for incoming payload. At the time SMB read response comes back, the data is already transferred and placed in the pages by RDMA hardware. When SMB read is finished, deregister the memory regions if RDMA write is used for this SMB read. smbd_deregister_mr may need to do local invalidation and sleep, if server remote invalidation is not used. There are situations where the MID may not be created on I/O failure, under which memory region is deregistered when read data context is released. Signed-off-by: Long Li <longli@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/cifs/file.c17
-rw-r--r--fs/cifs/smb2pdu.c45
2 files changed, 59 insertions, 3 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 3a85df2a9baf..7cee97b93a61 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -42,7 +42,7 @@
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "fscache.h"
-
+#include "smbdirect.h"
static inline int cifs_convert_flags(unsigned int flags)
{
@@ -2902,7 +2902,12 @@ cifs_readdata_release(struct kref *refcount)
{
struct cifs_readdata *rdata = container_of(refcount,
struct cifs_readdata, refcount);
-
+#ifdef CONFIG_CIFS_SMB_DIRECT
+ if (rdata->mr) {
+ smbd_deregister_mr(rdata->mr);
+ rdata->mr = NULL;
+ }
+#endif
if (rdata->cfile)
cifsFileInfo_put(rdata->cfile);
@@ -3031,6 +3036,10 @@ uncached_fill_pages(struct TCP_Server_Info *server,
}
if (iter)
result = copy_page_from_iter(page, 0, n, iter);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+ else if (rdata->mr)
+ result = n;
+#endif
else
result = cifs_read_page_from_socket(server, page, n);
if (result < 0)
@@ -3598,6 +3607,10 @@ readpages_fill_pages(struct TCP_Server_Info *server,
if (iter)
result = copy_page_from_iter(page, 0, n, iter);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+ else if (rdata->mr)
+ result = n;
+#endif
else
result = cifs_read_page_from_socket(server, page, n);
if (result < 0)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 908d7770d15a..bee0871d6dda 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2458,7 +2458,40 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
req->MinimumCount = 0;
req->Length = cpu_to_le32(io_parms->length);
req->Offset = cpu_to_le64(io_parms->offset);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+ /*
+ * If we want to do a RDMA write, fill in and append
+ * smbd_buffer_descriptor_v1 to the end of read request
+ */
+ if (server->rdma && rdata &&
+ rdata->bytes >= server->smbd_conn->rdma_readwrite_threshold) {
+
+ struct smbd_buffer_descriptor_v1 *v1;
+ bool need_invalidate =
+ io_parms->tcon->ses->server->dialect == SMB30_PROT_ID;
+
+ rdata->mr = smbd_register_mr(
+ server->smbd_conn, rdata->pages,
+ rdata->nr_pages, rdata->tailsz,
+ true, need_invalidate);
+ if (!rdata->mr)
+ return -ENOBUFS;
+
+ req->Channel = SMB2_CHANNEL_RDMA_V1_INVALIDATE;
+ if (need_invalidate)
+ req->Channel = SMB2_CHANNEL_RDMA_V1;
+ req->ReadChannelInfoOffset =
+ offsetof(struct smb2_read_plain_req, Buffer);
+ req->ReadChannelInfoLength =
+ sizeof(struct smbd_buffer_descriptor_v1);
+ v1 = (struct smbd_buffer_descriptor_v1 *) &req->Buffer[0];
+ v1->offset = rdata->mr->mr->iova;
+ v1->token = rdata->mr->mr->rkey;
+ v1->length = rdata->mr->mr->length;
+ *total_len += sizeof(*v1) - 1;
+ }
+#endif
if (request_type & CHAINED_REQUEST) {
if (!(request_type & END_OF_CHAIN)) {
/* next 8-byte aligned request */
@@ -2537,7 +2570,17 @@ smb2_readv_callback(struct mid_q_entry *mid)
if (rdata->result != -ENODATA)
rdata->result = -EIO;
}
-
+#ifdef CONFIG_CIFS_SMB_DIRECT
+ /*
+ * If this rdata has a memmory registered, the MR can be freed
+ * MR needs to be freed as soon as I/O finishes to prevent deadlock
+ * because they have limited number and are used for future I/Os
+ */
+ if (rdata->mr) {
+ smbd_deregister_mr(rdata->mr);
+ rdata->mr = NULL;
+ }
+#endif
if (rdata->result)
cifs_stats_fail_inc(tcon, SMB2_READ_HE);