2018-07-31 16:26 GMT-07:00 Ronnie Sahlberg <lsahlber@xxxxxxxxxx>:
> Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> ---
> fs/cifs/smb2ops.c | 39 ++++++++++++++++++++++++++++++++++++---
> 1 file changed, 36 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 81ff2bd6ceaa..10b888b954e4 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -2930,11 +2930,14 @@ static int
> receive_encrypted_standard(struct TCP_Server_Info *server,
> struct mid_q_entry **mid)
> {
> - int length;
> + int ret, length;
> char *buf = server->smallbuf;
> + struct smb2_sync_hdr *shdr;
> unsigned int pdu_length = server->pdu_size;
> unsigned int buf_size;
> struct mid_q_entry *mid_entry;
> + int next_is_large;
> + char *next_buffer = NULL;
>
> /* switch to large buffer if too big for a small one */
> if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE) {
> @@ -2955,6 +2958,21 @@ receive_encrypted_standard(struct TCP_Server_Info *server,
> if (length)
> return length;
>
> + next_is_large = server->large_buf;
> + one_more:
> + shdr = (struct smb2_sync_hdr *)buf;
> + if (shdr->NextCommand) {
> + if (next_is_large) {
> + next_buffer = (char *)cifs_buf_get();
> + memcpy(next_buffer, server->bigbuf + shdr->NextCommand,
> + pdu_length - shdr->NextCommand);
> + } else {
> + next_buffer = (char *)cifs_small_buf_get();
> + memcpy(next_buffer, server->smallbuf + shdr->NextCommand,
> + pdu_length - shdr->NextCommand);
> + }
> + }
> +
> mid_entry = smb2_find_mid(server, buf);
> if (mid_entry == NULL)
> cifs_dbg(FYI, "mid not found\n");
> @@ -2962,13 +2980,28 @@ receive_encrypted_standard(struct TCP_Server_Info *server,
> cifs_dbg(FYI, "mid found\n");
> mid_entry->decrypted = true;
> }
> + mid_entry->resp_buf_size = server->pdu_size;
>
> *mid = mid_entry;
demultiplex thread calls receive_encrypted_standard() with double
pointer to mid to populate, so it can issue mid->callback to wake up a
thread waiting for a specific mid. Now in receive_encrypted_standard()
we process several mids but save only the last one in the output thus
demultiplex thread will only call mid->callback for the last message
in a chain.
In the same time in compound_send_recv() we call wait_for_response()
for every mid in a compounded chain. Doesn't it mean that we will wait
forever or am I missing something?
>
> if (mid_entry && mid_entry->handle)
> - return mid_entry->handle(server, mid_entry);
> + ret = mid_entry->handle(server, mid_entry);
> + else
> + ret = cifs_handle_standard(server, mid_entry);
> +
> + if (ret == 0 && shdr->NextCommand) {
> + pdu_length -= shdr->NextCommand;
> + server->large_buf = next_is_large;
> + if (next_is_large) {
> + server->bigbuf = next_buffer;
> + } else {
> + server->smallbuf = next_buffer;
> + }
> + buf += shdr->NextCommand;
> + goto one_more;
> + }
>
> - return cifs_handle_standard(server, mid_entry);
> + return ret;
> }
>
> static int
> --
> 2.13.3
>
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