From: Long Li <lon...@microsoft.com>

The data buffer allocated on the stack can't be DMA'ed, and hence can't send
through RDMA via SMB Direct.

Fix this by allocating the request on the heap in smb3_validate_negotiate.

Signed-off-by: Long Li <lon...@microsoft.com>
---
 fs/cifs/smb2pdu.c | 38 ++++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 0f044c4..abbefe2 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -730,7 +730,7 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 {
        int rc = 0;
-       struct validate_negotiate_info_req vneg_inbuf;
+       struct validate_negotiate_info_req *pneg_inbuf;
        struct validate_negotiate_info_rsp *pneg_rsp = NULL;
        u32 rsplen;
        u32 inbuflen; /* max of 4 dialects */
@@ -741,6 +741,9 @@ int smb3_validate_negotiate(const unsigned int xid, struct 
cifs_tcon *tcon)
        if (tcon->ses->server->rdma)
                return 0;
 #endif
+       pneg_inbuf = kmalloc(sizeof(*pneg_inbuf), GFP_KERNEL);
+       if (!pneg_inbuf)
+               return -ENOMEM;
 
        /* In SMB3.11 preauth integrity supersedes validate negotiate */
        if (tcon->ses->server->dialect == SMB311_PROT_ID)
@@ -764,52 +767,53 @@ int smb3_validate_negotiate(const unsigned int xid, 
struct cifs_tcon *tcon)
        if (tcon->ses->session_flags & SMB2_SESSION_FLAG_IS_NULL)
                cifs_dbg(VFS, "Unexpected null user (anonymous) auth flag sent 
by server\n");
 
-       vneg_inbuf.Capabilities =
+       pneg_inbuf->Capabilities =
                        cpu_to_le32(tcon->ses->server->vals->req_capabilities);
-       memcpy(vneg_inbuf.Guid, tcon->ses->server->client_guid,
+       memcpy(pneg_inbuf->Guid, tcon->ses->server->client_guid,
                                        SMB2_CLIENT_GUID_SIZE);
 
        if (tcon->ses->sign)
-               vneg_inbuf.SecurityMode =
+               pneg_inbuf->SecurityMode =
                        cpu_to_le16(SMB2_NEGOTIATE_SIGNING_REQUIRED);
        else if (global_secflags & CIFSSEC_MAY_SIGN)
-               vneg_inbuf.SecurityMode =
+               pneg_inbuf->SecurityMode =
                        cpu_to_le16(SMB2_NEGOTIATE_SIGNING_ENABLED);
        else
-               vneg_inbuf.SecurityMode = 0;
+               pneg_inbuf->SecurityMode = 0;
 
 
        if (strcmp(tcon->ses->server->vals->version_string,
                SMB3ANY_VERSION_STRING) == 0) {
-               vneg_inbuf.Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
-               vneg_inbuf.Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
-               vneg_inbuf.DialectCount = cpu_to_le16(2);
+               pneg_inbuf->Dialects[0] = cpu_to_le16(SMB30_PROT_ID);
+               pneg_inbuf->Dialects[1] = cpu_to_le16(SMB302_PROT_ID);
+               pneg_inbuf->DialectCount = cpu_to_le16(2);
                /* structure is big enough for 3 dialects, sending only 2 */
                inbuflen = sizeof(struct validate_negotiate_info_req) - 2;
        } else if (strcmp(tcon->ses->server->vals->version_string,
                SMBDEFAULT_VERSION_STRING) == 0) {
-               vneg_inbuf.Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
-               vneg_inbuf.Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
-               vneg_inbuf.Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
-               vneg_inbuf.DialectCount = cpu_to_le16(3);
+               pneg_inbuf->Dialects[0] = cpu_to_le16(SMB21_PROT_ID);
+               pneg_inbuf->Dialects[1] = cpu_to_le16(SMB30_PROT_ID);
+               pneg_inbuf->Dialects[2] = cpu_to_le16(SMB302_PROT_ID);
+               pneg_inbuf->DialectCount = cpu_to_le16(3);
                /* structure is big enough for 3 dialects */
                inbuflen = sizeof(struct validate_negotiate_info_req);
        } else {
                /* otherwise specific dialect was requested */
-               vneg_inbuf.Dialects[0] =
+               pneg_inbuf->Dialects[0] =
                        cpu_to_le16(tcon->ses->server->vals->protocol_id);
-               vneg_inbuf.DialectCount = cpu_to_le16(1);
+               pneg_inbuf->DialectCount = cpu_to_le16(1);
                /* structure is big enough for 3 dialects, sending only 1 */
                inbuflen = sizeof(struct validate_negotiate_info_req) - 4;
        }
 
        rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
                FSCTL_VALIDATE_NEGOTIATE_INFO, true /* is_fsctl */,
-               (char *)&vneg_inbuf, sizeof(struct validate_negotiate_info_req),
+               (char *)pneg_inbuf, sizeof(struct validate_negotiate_info_req),
                (char **)&pneg_rsp, &rsplen);
 
        if (rc != 0) {
                cifs_dbg(VFS, "validate protocol negotiate failed: %d\n", rc);
+               kfree(pneg_inbuf);
                return -EIO;
        }
 
@@ -838,12 +842,14 @@ int smb3_validate_negotiate(const unsigned int xid, 
struct cifs_tcon *tcon)
 
        /* validate negotiate successful */
        cifs_dbg(FYI, "validate negotiate info successful\n");
+       kfree(pneg_inbuf);
        kfree(pneg_rsp);
        return 0;
 
 vneg_out:
        cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
 err_rsp_free:
+       kfree(pneg_inbuf);
        kfree(pneg_rsp);
        return -EIO;
 }
-- 
2.7.4

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