[CIFS] rmmod cifs can oops if done soon after the last cifs unmount

Signed-off-by: Shaggy (shaggy@austin.ibm.com)
Signed-off-by: Steve French (sfrench@us.ibm.com)

1 files changed, 18 insertions, 7 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9e8256003f73..ef0432c44482 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -29,6 +29,7 @@
 #include <linux/utsname.h>
 #include <linux/mempool.h>
 #include <linux/delay.h>
+#include <linux/completion.h>
 #include <asm/uaccess.h>
 #include <asm/processor.h>
 #include "cifspdu.h"
@@ -44,6 +45,8 @@
 #define CIFS_PORT 445
 #define RFC1001_PORT 139
 
+static DECLARE_COMPLETION(cifsd_complete);
+
 extern void SMBencrypt(unsigned char *passwd, unsigned char *c8,
                        unsigned char *p24);
 extern void SMBNTencrypt(unsigned char *passwd, unsigned char *c8,
@@ -339,6 +342,7 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
         atomic_inc(&tcpSesAllocCount);
         length = tcpSesAllocCount.counter;
         write_unlock(&GlobalSMBSeslock);
+        complete(&cifsd_complete);
         if(length  > 1) {
                 mempool_resize(cifs_req_poolp,
                         length + cifs_min_rcv,
@@ -676,7 +680,7 @@ multi_t2_fnd:
                 msleep(125);
         }
 
-        if (list_empty(&server->pending_mid_q)) {
+        if (!list_empty(&server->pending_mid_q)) {
                 /* mpx threads have not exited yet give them 
                 at least the smb send timeout time for long ops */
                 /* due to delays on oplock break requests, we need
@@ -713,7 +717,7 @@ multi_t2_fnd:
                         GFP_KERNEL);
         }
         
-        msleep(250);
+        complete_and_exit(&cifsd_complete, 0);
         return 0;
 }
 
@@ -1617,8 +1621,9 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                                         kfree(volume_info.password);
                                 FreeXid(xid);
                                 return rc;
-                        } else
-                                rc = 0;
+                        }
+                        wait_for_completion(&cifsd_complete);
+                        rc = 0;
                         memcpy(srvTcp->workstation_RFC1001_name, volume_info.source_rfc1001_name,16);
                         srvTcp->sequence_number = 0;
                 }
@@ -1759,8 +1764,10 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                         spin_lock(&GlobalMid_Lock);
                         srvTcp->tcpStatus = CifsExiting;
                         spin_unlock(&GlobalMid_Lock);
-                        if(srvTcp->tsk)
+                        if(srvTcp->tsk) {
                                 send_sig(SIGKILL,srvTcp->tsk,1);
+                                wait_for_completion(&cifsd_complete);
+                        }
                 }
                  /* If find_unc succeeded then rc == 0 so we can not end */
                 if (tcon)  /* up accidently freeing someone elses tcon struct */
@@ -1773,8 +1780,10 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
                                         temp_rc = CIFSSMBLogoff(xid, pSesInfo);
                                         /* if the socketUseCount is now zero */
                                         if((temp_rc == -ESHUTDOWN) &&
-                                           (pSesInfo->server->tsk))
+                                           (pSesInfo->server->tsk)) {
                                                 send_sig(SIGKILL,pSesInfo->server->tsk,1);
+                                                wait_for_completion(&cifsd_complete);
+                                        }
                                 } else
                                         cFYI(1, ("No session or bad tcon"));
                                 sesInfoFree(pSesInfo);
@@ -3241,8 +3250,10 @@ cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
                                 return 0;
                         } else if (rc == -ESHUTDOWN) {
                                 cFYI(1,("Waking up socket by sending it signal"));
-                                if(cifsd_task)
+                                if(cifsd_task) {
                                         send_sig(SIGKILL,cifsd_task,1);
+                                        wait_for_completion(&cifsd_complete);
+                                }
                                 rc = 0;
                         } /* else - we have an smb session
                                 left on this socket do not kill cifsd */