Commit 9b646972 authored by Tejun Heo's avatar Tejun Heo
Browse files

cifs: use workqueue instead of slow-work 



Workqueue can now handle high concurrency.  Use system_nrt_wq
instead of slow-work.

* Updated is_valid_oplock_break() to not call cifs_oplock_break_put()
  as advised by Steve French.  It might cause deadlock.  Instead,
  reference is increased after queueing succeeded and
  cifs_oplock_break() briefly grabs GlobalSMBSeslock before putting
  the cfile to make sure it doesn't put before the matching get is
  finished.

* Anton Blanchard reported that cifs conversion was using now gone
  system_single_wq.  Use system_nrt_wq which provides non-reentrance
  guarantee which is enough and much better.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarSteve French <sfrench@samba.org>
Cc: Anton Blanchard <anton@samba.org>
parent d098adfb

fs/cifs/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -2,7 +2,6 @@ config CIFS 
	tristate "CIFS support (advanced network filesystem, SMBFS successor)"

	depends on INET

	select NLS

	select SLOW_WORK

	help

	  This is the client VFS module for the Common Internet File System

	  (CIFS) protocol which is the successor to the Server Message Block

fs/cifs/cifsfs.c

+0 −5
Original line number Diff line number Diff line
@@ -917,15 +917,10 @@ init_cifs(void) 
	if (rc)

		goto out_unregister_key_type;

#endif

	rc = slow_work_register_user(THIS_MODULE);

	if (rc)

		goto out_unregister_resolver_key;



	return 0;



 out_unregister_resolver_key:

#ifdef CONFIG_CIFS_DFS_UPCALL

	unregister_key_type(&key_type_dns_resolver);

 out_unregister_key_type:

#endif

#ifdef CONFIG_CIFS_UPCALL

fs/cifs/cifsglob.h

+5 −3
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ 
#include <linux/in.h>

#include <linux/in6.h>

#include <linux/slab.h>

#include <linux/slow-work.h>

#include <linux/workqueue.h>

#include "cifs_fs_sb.h"

#include "cifsacl.h"

/*
@@ -363,7 +363,7 @@ struct cifsFileInfo { 
	atomic_t count;		/* reference count */

	struct mutex fh_mutex; /* prevents reopen race after dead ses*/

	struct cifs_search_info srch_inf;

	struct slow_work oplock_break; /* slow_work job for oplock breaks */

	struct work_struct oplock_break; /* work for oplock breaks */

};



/* Take a reference on the file private data */
@@ -732,4 +732,6 @@ GLOBAL_EXTERN unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */ 
GLOBAL_EXTERN unsigned int cifs_min_small;  /* min size of small buf pool */

GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/



extern const struct slow_work_ops cifs_oplock_break_ops;
 
void cifs_oplock_break(struct work_struct *work);

void cifs_oplock_break_get(struct cifsFileInfo *cfile);

void cifs_oplock_break_put(struct cifsFileInfo *cfile);

fs/cifs/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -162,7 +162,7 @@ cifs_new_fileinfo(struct inode *newinode, __u16 fileHandle, 
	mutex_init(&pCifsFile->lock_mutex);

	INIT_LIST_HEAD(&pCifsFile->llist);

	atomic_set(&pCifsFile->count, 1);

	slow_work_init(&pCifsFile->oplock_break, &cifs_oplock_break_ops);

	INIT_WORK(&pCifsFile->oplock_break, cifs_oplock_break);



	write_lock(&GlobalSMBSeslock);

	list_add(&pCifsFile->tlist, &cifs_sb->tcon->openFileList);

fs/cifs/file.c

+13 −17
Original line number Diff line number Diff line
@@ -2295,8 +2295,7 @@ out: 
	return rc;

}



static void

cifs_oplock_break(struct slow_work *work)

void cifs_oplock_break(struct work_struct *work)

{

	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,

						  oplock_break);
@@ -2333,33 +2332,30 @@ cifs_oplock_break(struct slow_work *work) 
				 LOCKING_ANDX_OPLOCK_RELEASE, false);

		cFYI(1, "Oplock release rc = %d", rc);

	}



	/*

	 * We might have kicked in before is_valid_oplock_break()

	 * finished grabbing reference for us.  Make sure it's done by

	 * waiting for GlobalSMSSeslock.

	 */

	write_lock(&GlobalSMBSeslock);

	write_unlock(&GlobalSMBSeslock);



	cifs_oplock_break_put(cfile);

}



static int

cifs_oplock_break_get(struct slow_work *work)

void cifs_oplock_break_get(struct cifsFileInfo *cfile)

{

	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,

						  oplock_break);

	mntget(cfile->mnt);

	cifsFileInfo_get(cfile);

	return 0;

}



static void

cifs_oplock_break_put(struct slow_work *work)

void cifs_oplock_break_put(struct cifsFileInfo *cfile)

{

	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,

						  oplock_break);

	mntput(cfile->mnt);

	cifsFileInfo_put(cfile);

}



const struct slow_work_ops cifs_oplock_break_ops = {

	.get_ref	= cifs_oplock_break_get,

	.put_ref	= cifs_oplock_break_put,

	.execute	= cifs_oplock_break,

};



const struct address_space_operations cifs_addr_ops = {

	.readpage = cifs_readpage,

	.readpages = cifs_readpages,

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