cifs: move buffer pointers into TCP_Server_Info

We have several functions that need to access these pointers. Currently
that's done with a lot of double pointer passing. Instead, move them
into the TCP_Server_Info and simplify the handling.

Reviewed-and-Tested-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 46 insertions, 55 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 8d5a61561909..8918f935bf07 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -320,27 +320,24 @@ requeue_echo:
 }
 
 static bool
-allocate_buffers(char **bigbuf, char **smallbuf, unsigned int size,
-                 bool is_large_buf)
+allocate_buffers(struct TCP_Server_Info *server)
 {
-        char *bbuf = *bigbuf, *sbuf = *smallbuf;
-
-        if (bbuf == NULL) {
-                bbuf = (char *)cifs_buf_get();
-                if (!bbuf) {
+        if (!server->bigbuf) {
+                server->bigbuf = (char *)cifs_buf_get();
+                if (!server->bigbuf) {
                         cERROR(1, "No memory for large SMB response");
                         msleep(3000);
                         /* retry will check if exiting */
                         return false;
                 }
-        } else if (is_large_buf) {
+        } else if (server->large_buf) {
                 /* we are reusing a dirty large buf, clear its start */
-                memset(bbuf, 0, size);
+                memset(server->bigbuf, 0, sizeof(struct smb_hdr));
         }
 
-        if (sbuf == NULL) {
-                sbuf = (char *)cifs_small_buf_get();
-                if (!sbuf) {
+        if (!server->smallbuf) {
+                server->smallbuf = (char *)cifs_small_buf_get();
+                if (!server->smallbuf) {
                         cERROR(1, "No memory for SMB response");
                         msleep(1000);
                         /* retry will check if exiting */
@@ -349,12 +346,9 @@ allocate_buffers(char **bigbuf, char **smallbuf, unsigned int size,
                 /* beginning of smb buffer is cleared in our buf_get */
         } else {
                 /* if existing small buf clear beginning */
-                memset(sbuf, 0, size);
+                memset(server->smallbuf, 0, sizeof(struct smb_hdr));
         }
 
-        *bigbuf = bbuf;
-        *smallbuf = sbuf;
-
         return true;
 }
 
@@ -576,7 +570,7 @@ dequeue_mid(struct mid_q_entry *mid, int malformed)
 
 static struct mid_q_entry *
 find_cifs_mid(struct TCP_Server_Info *server, struct smb_hdr *buf,
-              int malformed, bool is_large_buf, char **bigbuf)
+              int malformed)
 {
         struct mid_q_entry *mid = NULL;
 
@@ -596,19 +590,27 @@ find_cifs_mid(struct TCP_Server_Info *server, struct smb_hdr *buf,
                         mid->multiEnd = true;
                         goto multi_t2_fnd;
                 }
-                if (!is_large_buf) {
+                if (!server->large_buf) {
                         /*FIXME: switch to already allocated largebuf?*/
                         cERROR(1, "1st trans2 resp needs bigbuf");
                 } else {
                         /* Have first buffer */
                         mid->resp_buf = buf;
                         mid->largeBuf = true;
-                        *bigbuf = NULL;
+                        server->bigbuf = NULL;
                 }
                 return mid;
         }
         mid->resp_buf = buf;
-        mid->largeBuf = is_large_buf;
+        mid->largeBuf = server->large_buf;
+        /* Was previous buf put in mpx struct for multi-rsp? */
+        if (!mid->multiRsp) {
+                /* smb buffer will be freed by user thread */
+                if (server->large_buf)
+                        server->bigbuf = NULL;
+                else
+                        server->smallbuf = NULL;
+        }
 multi_t2_fnd:
         dequeue_mid(mid, malformed);
         return mid;
@@ -715,12 +717,11 @@ cifs_demultiplex_thread(void *p)
 {
         int length;
         struct TCP_Server_Info *server = p;
-        unsigned int pdu_length, total_read;
-        char *buf = NULL, *bigbuf = NULL, *smallbuf = NULL;
+        unsigned int pdu_length;
+        char *buf = NULL;
         struct smb_hdr *smb_buffer = NULL;
         struct task_struct *task_to_wake = NULL;
         struct mid_q_entry *mid_entry;
-        bool isLargeBuf = false;
 
         current->flags |= PF_MEMALLOC;
         cFYI(1, "Demultiplex PID: %d", task_pid_nr(current));
@@ -735,19 +736,18 @@ cifs_demultiplex_thread(void *p)
                 if (try_to_freeze())
                         continue;
 
-                if (!allocate_buffers(&bigbuf, &smallbuf,
-                                      sizeof(struct smb_hdr), isLargeBuf))
+                if (!allocate_buffers(server))
                         continue;
 
-                isLargeBuf = false;
-                smb_buffer = (struct smb_hdr *)smallbuf;
-                buf = smallbuf;
+                server->large_buf = false;
+                smb_buffer = (struct smb_hdr *)server->smallbuf;
+                buf = server->smallbuf;
                 pdu_length = 4; /* enough to get RFC1001 header */
 
                 length = read_from_socket(server, buf, pdu_length);
                 if (length < 0)
                         continue;
-                total_read = length;
+                server->total_read = length;
 
                 /*
                  * The right amount was read from socket - 4 bytes,
@@ -773,7 +773,7 @@ cifs_demultiplex_thread(void *p)
                                           sizeof(struct smb_hdr) - 1 - 4);
                 if (length < 0)
                         continue;
-                total_read += length;
+                server->total_read += length;
 
                 if (pdu_length > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4) {
                         cERROR(1, "SMB response too long (%u bytes)",
@@ -785,10 +785,11 @@ cifs_demultiplex_thread(void *p)
 
                 /* else length ok */
                 if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE - 4) {
-                        isLargeBuf = true;
-                        memcpy(bigbuf, smallbuf, total_read);
-                        smb_buffer = (struct smb_hdr *)bigbuf;
-                        buf = bigbuf;
+                        server->large_buf = true;
+                        memcpy(server->bigbuf, server->smallbuf,
+                               server->total_read);
+                        smb_buffer = (struct smb_hdr *)server->bigbuf;
+                        buf = server->bigbuf;
                 }
 
                 /* now read the rest */
@@ -797,9 +798,9 @@ cifs_demultiplex_thread(void *p)
                                   pdu_length - sizeof(struct smb_hdr) + 1 + 4);
                 if (length < 0)
                         continue;
-                total_read += length;
+                server->total_read += length;
 
-                dump_smb(smb_buffer, total_read);
+                dump_smb(smb_buffer, server->total_read);
 
                 /*
                  * We know that we received enough to get to the MID as we
@@ -810,28 +811,18 @@ cifs_demultiplex_thread(void *p)
                  * 48 bytes is enough to display the header and a little bit
                  * into the payload for debugging purposes.
                  */
-                length = checkSMB(smb_buffer, smb_buffer->Mid, total_read);
+                length = checkSMB(smb_buffer, smb_buffer->Mid,
+                                  server->total_read);
                 if (length != 0)
                         cifs_dump_mem("Bad SMB: ", buf,
-                                      min_t(unsigned int, total_read, 48));
+                                min_t(unsigned int, server->total_read, 48));
 
                 server->lstrp = jiffies;
 
-                mid_entry = find_cifs_mid(server, smb_buffer, length,
-                                          isLargeBuf, &bigbuf);
+                mid_entry = find_cifs_mid(server, smb_buffer, length);
                 if (mid_entry != NULL) {
-                        if (mid_entry->multiRsp && !mid_entry->multiEnd)
-                                continue;
-
-                        /* Was previous buf put in mpx struct for multi-rsp? */
-                        if (!mid_entry->multiRsp) {
-                                /* smb buffer will be freed by user thread */
-                                if (isLargeBuf)
-                                        bigbuf = NULL;
-                                else
-                                        smallbuf = NULL;
-                        }
-                        mid_entry->callback(mid_entry);
+                        if (!mid_entry->multiRsp || mid_entry->multiEnd)
+                                mid_entry->callback(mid_entry);
                 } else if (length != 0) {
                         /* response sanity checks failed */
                         continue;
@@ -849,9 +840,9 @@ cifs_demultiplex_thread(void *p)
         } /* end while !EXITING */
 
         /* buffer usually freed in free_mid - need to free it here on exit */
-        cifs_buf_release(bigbuf);
-        if (smallbuf) /* no sense logging a debug message if NULL */
-                cifs_small_buf_release(smallbuf);
+        cifs_buf_release(server->bigbuf);
+        if (server->smallbuf) /* no sense logging a debug message if NULL */
+                cifs_small_buf_release(server->smallbuf);
 
         task_to_wake = xchg(&server->tsk, NULL);
         clean_demultiplex_info(server);