Re: cifs and kthread_run / kernel_thread

Re: cifs and kthread_run / kernel_thread

[Steve French (smfltc)]

>Hi all,
>
>I would like to use cifs inside linux-vserver guests. Discussion this with the 
>vserver people, we found that cifs is using the new kthread_run and the old 
>kernel_thread interface for starting kernel-threads. The old-style interface 
>renders cifs unusable inside a vserver-guest :-(
>
>My questions:
>
>i) Are there newer versions of cifs, where only kthread_run is used in all 
>places?
>
>  
>
No - IIRC the original patch (for the switch of cifs from kernel_thread 
to kthread) had a
minor implementation problem in handling the cifs_demultiplex thread, so 
this one small
area was left with the old style.

>iii) Is it difficult to switch to the new interface?
>  
>
No, I don't think so, but I have not investigated it.  We would be happy
to review and test a patch for this though.

>gs cifs # grep kthread_run *.[ch]
>cifsfs.c:       oplockThread = kthread_run(cifs_oplock_thread, 
>NULL, "cifsoplockd");
>cifsfs.c:       dnotifyThread = kthread_run(cifs_dnotify_thread, 
>NULL, "cifsdnotifyd");
>
>gs cifs # grep kernel_thread *.[ch]
>cifs.mod.c:     { 0x7e9ebb05, "kernel_thread" },
>connect.c:                      rc = (int)kernel_thread((void *)(void 
>*)cifs_demultiplex_thread, srvTcp,
>
>
>Thx,
>
>Wilhelm
>
>*********************************************
>  
>

Re: [linux-cifs-client] Re: cifs and kthread_run / kernel_thread

[Q (Igor Mammedov)]

Steve French (smfltc) wrote:
> 
>> Hi all,
>>
>> I would like to use cifs inside linux-vserver guests. Discussion this 
>> with the vserver people, we found that cifs is using the new 
>> kthread_run and the old kernel_thread interface for starting 
>> kernel-threads. The old-style interface renders cifs unusable inside a 
>> vserver-guest :-(
>>
>> My questions:
>>
>> i) Are there newer versions of cifs, where only kthread_run is used in 
>> all places?
>>
>>  
>>
> No - IIRC the original patch (for the switch of cifs from kernel_thread 
> to kthread) had a
> minor implementation problem in handling the cifs_demultiplex thread, so 
> this one small
> area was left with the old style.
> 
>> iii) Is it difficult to switch to the new interface?
>>  
>>
> No, I don't think so, but I have not investigated it.  We would be happy
> to review and test a patch for this though.
> 
>> gs cifs # grep kthread_run *.[ch]
>> cifsfs.c:       oplockThread = kthread_run(cifs_oplock_thread, NULL, 
>> "cifsoplockd");
>> cifsfs.c:       dnotifyThread = kthread_run(cifs_dnotify_thread, NULL, 
>> "cifsdnotifyd");
>>
>> gs cifs # grep kernel_thread *.[ch]
>> cifs.mod.c:     { 0x7e9ebb05, "kernel_thread" },
>> connect.c:                      rc = (int)kernel_thread((void *)(void 
>> *)cifs_demultiplex_thread, srvTcp,
>>
>>
>> Thx,
>>
>> Wilhelm
>>
>> *****************************************

It seems to me that I rewrote cifs_demultiplex_thread to use kthread_run 
in DFS patch.

-- 

Best regards,

-------------------------
Igor Mammedov,
niallain "at" gmail.com

Re: [linux-cifs-client] Re: cifs and kthread_run / kernel_thread

[Wilhelm Meier]

Hi Steve, hi Igor,

Am Montag, 2. April 2007 schrieb Q (Igor Mammedov):
> >
> > No - IIRC the original patch (for the switch of cifs from kernel_thread
> > to kthread) had a
> > minor implementation problem in handling the cifs_demultiplex thread, so
> > this one small
> > area was left with the old style.

can you remember what the problems (if any) were with this patch from Igor?

>
> It seems to me that I rewrote cifs_demultiplex_thread to use kthread_run
> in DFS patch.

o.k., I found the patch on the list. Will do some testing with it.

-
Wilhelm

Re: [linux-cifs-client] Re: cifs and kthread_run / kernel_thread

[Steve French (smfltc)]

Q (Igor Mammedov) wrote:

> Steve French (smfltc) wrote:
>
>> No - IIRC the original patch (for the switch of cifs from 
>> kernel_thread to kthread) had a
>> minor implementation problem in handling the cifs_demultiplex thread, 
>> so this one small
>> area was left with the old style.
>>
>>> iii) Is it difficult to switch to the new interface?
>>>  
>>>
>> No, I don't think so, but I have not investigated it.  We would be happy
>> to review and test a patch for this though.
>>
>>> ***************************
>>
>
> It seems to me that I rewrote cifs_demultiplex_thread to use 
> kthread_run in DFS patch.
>
Yes - Q's  patch has the final change to kthread (as part of a larger 
DFS change).  The original
patch which switched to kthread was done long before this.

I have not broken all the large dfs patch into small pieces but will 
look to see if just this part
can be done easily

Re: [linux-cifs-client] Re: cifs and kthread_run / kernel_thread

[Wilhelm Meier]

[-- Attachment #1: Type: text/plain, Size: 477 bytes --]

Am Montag, 2. April 2007 schrieb Wilhelm Meier:
>
> > It seems to me that I rewrote cifs_demultiplex_thread to use kthread_run
> > in DFS patch.
>
> o.k., I found the patch on the list. Will do some testing with it.

o.k., the patch seems to be fine for linux-vserver. cifs-mounting inside the 
guest is now possible.

Do you see any possiblility to include this part of Igors work (not the whole 
DFS thing) to the mainline? It fixes the use of the deprecated api.

-
Wilhelm

[-- Attachment #2: cifs_kthread.diff --]
[-- Type: text/x-diff, Size: 3951 bytes --]

Index: connect.c
===================================================================
--- connect.c	(.../2.6.19.1)	(revision 20)
+++ connect.c	(.../kthread_support)	(revision 20)
@@ -30,6 +30,7 @@
 #include <linux/mempool.h>
 #include <linux/delay.h>
 #include <linux/completion.h>
+#include <linux/kthread.h>
 #include <linux/pagevec.h>
 #include <asm/uaccess.h>
 #include <asm/processor.h>
@@ -119,7 +120,7 @@
 	struct mid_q_entry * mid_entry;
 	
 	spin_lock(&GlobalMid_Lock);
-	if(server->tcpStatus == CifsExiting) {
+	if( kthread_should_stop() ) {
 		/* the demux thread will exit normally 
 		next time through the loop */
 		spin_unlock(&GlobalMid_Lock);
@@ -181,7 +182,7 @@
 	spin_unlock(&GlobalMid_Lock);
 	up(&server->tcpSem); 
 
-	while ((server->tcpStatus != CifsExiting) && (server->tcpStatus != CifsGood))
+	while ( (!kthread_should_stop()) && (server->tcpStatus != CifsGood))
 	{
 		try_to_freeze();
 		if(server->protocolType == IPV6) {
@@ -198,7 +199,7 @@
 		} else {
 			atomic_inc(&tcpSesReconnectCount);
 			spin_lock(&GlobalMid_Lock);
-			if(server->tcpStatus != CifsExiting)
+			if( !kthread_should_stop() )
 				server->tcpStatus = CifsGood;
 			server->sequence_number = 0;
 			spin_unlock(&GlobalMid_Lock);			
@@ -344,7 +345,6 @@
 	int isMultiRsp;
 	int reconnect;
 
-	daemonize("cifsd");
 	allow_signal(SIGKILL);
 	current->flags |= PF_MEMALLOC;
 	server->tsk = current;	/* save process info to wake at shutdown */
@@ -360,7 +360,7 @@
 			GFP_KERNEL);
 	}
 
-	while (server->tcpStatus != CifsExiting) {
+	while (!kthread_should_stop()) {
 		if (try_to_freeze())
 			continue;
 		if (bigbuf == NULL) {
@@ -399,7 +399,7 @@
 		    kernel_recvmsg(csocket, &smb_msg,
 				 &iov, 1, 4, 0 /* BB see socket.h flags */);
 
-		if (server->tcpStatus == CifsExiting) {
+		if ( kthread_should_stop() ) {
 			break;
 		} else if (server->tcpStatus == CifsNeedReconnect) {
 			cFYI(1, ("Reconnect after server stopped responding"));
@@ -523,7 +523,7 @@
 		     total_read += length) {
 			length = kernel_recvmsg(csocket, &smb_msg, &iov, 1,
 						pdu_length - total_read, 0);
-			if((server->tcpStatus == CifsExiting) ||
+			if( kthread_should_stop() ||
 			    (length == -EINTR)) {
 				/* then will exit */
 				reconnect = 2;
@@ -756,7 +756,6 @@
 			GFP_KERNEL);
 	}
 	
-	complete_and_exit(&cifsd_complete, 0);
 	return 0;
 }
 
@@ -1779,10 +1778,11 @@
 			so no need to spinlock this init of tcpStatus */
 			srvTcp->tcpStatus = CifsNew;
 			init_MUTEX(&srvTcp->tcpSem);
-			rc = (int)kernel_thread((void *)(void *)cifs_demultiplex_thread, srvTcp,
-				      CLONE_FS | CLONE_FILES | CLONE_VM);
-			if(rc < 0) {
-				rc = -ENOMEM;
+			srvTcp->tsk = kthread_run((void *)(void *)cifs_demultiplex_thread, srvTcp, "cifsd");
+			if( IS_ERR(srvTcp->tsk) ) {
+				rc = PTR_ERR(srvTcp->tsk);
+				cERROR(1,("error %d create cifsd thread", rc));
+				srvTcp->tsk = NULL;
 				sock_release(csocket);
 				kfree(volume_info.UNC);
 				kfree(volume_info.password);
@@ -1973,7 +1973,7 @@
 			spin_unlock(&GlobalMid_Lock);
 			if(srvTcp->tsk) {
 				send_sig(SIGKILL,srvTcp->tsk,1);
-				wait_for_completion(&cifsd_complete);
+				kthread_stop(srvTcp->tsk);
 			}
 		}
 		 /* If find_unc succeeded then rc == 0 so we can not end */
@@ -1987,9 +1987,9 @@
 					temp_rc = CIFSSMBLogoff(xid, pSesInfo);
 					/* if the socketUseCount is now zero */
 					if((temp_rc == -ESHUTDOWN) &&
-					   (pSesInfo->server->tsk)) {
+					   (pSesInfo->server) && (pSesInfo->server->tsk)) {
 						send_sig(SIGKILL,pSesInfo->server->tsk,1);
-						wait_for_completion(&cifsd_complete);
+						kthread_stop(pSesInfo->server->tsk);
 					}
 				} else
 					cFYI(1, ("No session or bad tcon"));
@@ -3273,7 +3273,7 @@
 				cFYI(1,("Waking up socket by sending it signal"));
 				if(cifsd_task) {
 					send_sig(SIGKILL,cifsd_task,1);
-					wait_for_completion(&cifsd_complete);
+					kthread_stop(cifsd_task);
 				}
 				rc = 0;
 			} /* else - we have an smb session

Re: cifs and kthread_run / kernel_thread

[Steve French (smfltc)]

Wilhelm Meier wrote:

>m Montag, 2. April 2007 schrieb Wilhelm Meier:
>  
>
>>>It seems to me that I rewrote cifs_demultiplex_thread to use kthread_run
>>>in DFS patch.
>>>      
>>>
>>o.k., I found the patch on the list. Will do some testing with it.
>>    
>>
>
>o.k., the patch seems to be fine for linux-vserver. cifs-mounting inside the 
>guest is now possible.
>
>Do you see any possiblility to include this part of Igors work (not the whole 
>DFS thing) to the mainline? It fixes the use of the deprecated api.
>
>-
>Wilhelm
>  
>
>------------------------------------------------------------------------
>
>Index: connect.c
>===================================================================
>--- connect.c	(.../2.6.19.1)	(revision 20)
>+++ connect.c	(.../kthread_support)	(revision 20)
>@@ -30,6 +30,7 @@
> #include <linux/mempool.h>
> #include <linux/delay.h>
> #include <linux/completion.h>
>+#include <linux/kthread.h>
> #include <linux/pagevec.h>
> #include <asm/uaccess.h>
> #include <asm/processor.h>
>@@ -119,7 +120,7 @@
> 	struct mid_q_entry * mid_entry;
> 	
> 	spin_lock(&GlobalMid_Lock);
>-	if(server->tcpStatus == CifsExiting) {
>+	if( kthread_should_stop() ) {
> 		/* the demux thread will exit normally 
> 		next time through the loop */
> 		spin_unlock(&GlobalMid_Lock);
>@@ -181,7 +182,7 @@
> 	spin_unlock(&GlobalMid_Lock);
> 	up(&server->tcpSem); 
>
>-	while ((server->tcpStatus != CifsExiting) && (server->tcpStatus != CifsGood))
>+	while ( (!kthread_should_stop()) && (server->tcpStatus != CifsGood))
> 	{
> 		try_to_freeze();
> 		if(server->protocolType == IPV6) {
>@@ -198,7 +199,7 @@
> 		} else {
> 			atomic_inc(&tcpSesReconnectCount);
> 			spin_lock(&GlobalMid_Lock);
>-			if(server->tcpStatus != CifsExiting)
>+			if( !kthread_should_stop() )
> 				server->tcpStatus = CifsGood;
> 			server->sequence_number = 0;
> 			spin_unlock(&GlobalMid_Lock);			
>@@ -344,7 +345,6 @@
> 	int isMultiRsp;
> 	int reconnect;
>
>-	daemonize("cifsd");
> 	allow_signal(SIGKILL);
> 	current->flags |= PF_MEMALLOC;
> 	server->tsk = current;	/* save process info to wake at shutdown */
>@@ -360,7 +360,7 @@
> 			GFP_KERNEL);
> 	}
>
>-	while (server->tcpStatus != CifsExiting) {
>+	while (!kthread_should_stop()) {
> 		if (try_to_freeze())
> 			continue;
> 		if (bigbuf == NULL) {
>@@ -399,7 +399,7 @@
> 		    kernel_recvmsg(csocket, &smb_msg,
> 				 &iov, 1, 4, 0 /* BB see socket.h flags */);
>
>-		if (server->tcpStatus == CifsExiting) {
>+		if ( kthread_should_stop() ) {
> 			break;
> 		} else if (server->tcpStatus == CifsNeedReconnect) {
> 			cFYI(1, ("Reconnect after server stopped responding"));
>@@ -523,7 +523,7 @@
> 		     total_read += length) {
> 			length = kernel_recvmsg(csocket, &smb_msg, &iov, 1,
> 						pdu_length - total_read, 0);
>-			if((server->tcpStatus == CifsExiting) ||
>+			if( kthread_should_stop() ||
> 			    (length == -EINTR)) {
> 				/* then will exit */
> 				reconnect = 2;
>@@ -756,7 +756,6 @@
> 			GFP_KERNEL);
> 	}
> 	
>-	complete_and_exit(&cifsd_complete, 0);
> 	return 0;
> }
>
>@@ -1779,10 +1778,11 @@
> 			so no need to spinlock this init of tcpStatus */
> 			srvTcp->tcpStatus = CifsNew;
> 			init_MUTEX(&srvTcp->tcpSem);
>-			rc = (int)kernel_thread((void *)(void *)cifs_demultiplex_thread, srvTcp,
>-				      CLONE_FS | CLONE_FILES | CLONE_VM);
>-			if(rc < 0) {
>-				rc = -ENOMEM;
>+			srvTcp->tsk = kthread_run((void *)(void *)cifs_demultiplex_thread, srvTcp, "cifsd");
>+			if( IS_ERR(srvTcp->tsk) ) {
>+				rc = PTR_ERR(srvTcp->tsk);
>+				cERROR(1,("error %d create cifsd thread", rc));
>+				srvTcp->tsk = NULL;
> 				sock_release(csocket);
> 				kfree(volume_info.UNC);
> 				kfree(volume_info.password);
>@@ -1973,7 +1973,7 @@
> 			spin_unlock(&GlobalMid_Lock);
> 			if(srvTcp->tsk) {
> 				send_sig(SIGKILL,srvTcp->tsk,1);
>-				wait_for_completion(&cifsd_complete);
>+				kthread_stop(srvTcp->tsk);
> 			}
> 		}
> 		 /* If find_unc succeeded then rc == 0 so we can not end */
>@@ -1987,9 +1987,9 @@
> 					temp_rc = CIFSSMBLogoff(xid, pSesInfo);
> 					/* if the socketUseCount is now zero */
> 					if((temp_rc == -ESHUTDOWN) &&
>-					   (pSesInfo->server->tsk)) {
>+					   (pSesInfo->server) && (pSesInfo->server->tsk)) {
> 						send_sig(SIGKILL,pSesInfo->server->tsk,1);
>-						wait_for_completion(&cifsd_complete);
>+						kthread_stop(pSesInfo->server->tsk);
> 					}
> 				} else
> 					cFYI(1, ("No session or bad tcon"));
>@@ -3273,7 +3273,7 @@
> 				cFYI(1,("Waking up socket by sending it signal"));
> 				if(cifsd_task) {
> 					send_sig(SIGKILL,cifsd_task,1);
>-					wait_for_completion(&cifsd_complete);
>+					kthread_stop(cifsd_task);
> 				}
> 				rc = 0;
> 			} /* else - we have an smb session
>  
>
Yes.   I can merge this today in cifs-2.6 development tree after I try 
it out (and to 2.6.22 when it opens up
soon).

I also plan to merge a somewhat simpler change tothe inet_pton related 
change that Q made, since that can be
pulled out to make the final dfs change smaller to finish review (but it 
requires an additional change to
fs/cifs/connect.c to recognize ipv6 connections)..

Re: [linux-cifs-client] Re: cifs and kthread_run / kernel_thread

[Jeremy Allison]

On Tue, Apr 03, 2007 at 02:17:59PM -0500, Steve French wrote:

> Now merged into cifs-2.6 git tree.  Thanks to Q and Wilhelm

Up to date SVN please ! :-).

Jeremy.