From: Simon Wilkinson <sxw@inf.ed.ac.uk>
Date: Fri, 23 Apr 2010 17:39:14 +0000 (+0100)
Subject: Linux: Remove the BKL
X-Git-Tag: openafs-devel-1_5_75~108
X-Git-Url: https://git.openafs.org/?p=openafs.git;a=commitdiff_plain;h=196d2c7f9e3250008bf6aed2e172ec6d54e4ffb7

Linux: Remove the BKL

Recent investigations suggest that we no long require the BKL on
Linux. As an experiment, remove it.

Change-Id: I764fe1f6e9761ada5a0a86ba59450c0615bb1e78
Reviewed-on: http://gerrit.openafs.org/1823
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
---

diff --git a/src/afs/LINUX/osi_export.c b/src/afs/LINUX/osi_export.c
index 59a84db..5b300e0 100644
--- a/src/afs/LINUX/osi_export.c
+++ b/src/afs/LINUX/osi_export.c
@@ -545,13 +545,11 @@ static struct dentry *afs_export_get_dentry(struct super_block *sb,
     cred_t *credp;
 
     credp = crref();
-    lock_kernel();
     AFS_GLOCK();
 
     dp = get_dentry_from_fid(credp, inump);
 
     AFS_GUNLOCK();
-    unlock_kernel();
     crfree(credp);
 
     return dp;
@@ -609,7 +607,6 @@ static int afs_export_get_name(struct dentry *parent, char *name,
     afs_InitFakeStat(&fakestate);
 
     credp = crref();
-    lock_kernel();
     AFS_GLOCK();
 
     vcp = VTOAFS(child->d_inode);
@@ -818,7 +815,6 @@ done:
     }
     afs_PutFakeStat(&fakestate);
     AFS_GUNLOCK();
-    unlock_kernel();
     crfree(credp);
     code = afs_CheckCode(code, &treq, 102);
     return -code;
@@ -846,7 +842,6 @@ static struct dentry *afs_export_get_parent(struct dentry *child)
     }
 
     credp = crref();
-    lock_kernel();
     AFS_GLOCK();
 
     vcp = VTOAFS(child->d_inode);
@@ -938,7 +933,6 @@ static struct dentry *afs_export_get_parent(struct dentry *child)
 
 done:
     AFS_GUNLOCK();
-    unlock_kernel();
     crfree(credp);
 
     return dp;
diff --git a/src/afs/LINUX/osi_file.c b/src/afs/LINUX/osi_file.c
index 132c800..c0c589b 100644
--- a/src/afs/LINUX/osi_file.c
+++ b/src/afs/LINUX/osi_file.c
@@ -204,7 +204,6 @@ osi_UFSTruncate(register struct osi_file *afile, afs_int32 asize)
     newattrs.ia_ctime = CURRENT_TIME;
 
     /* avoid notify_change() since it wants to update dentry->d_parent */
-    lock_kernel();
     code = inode_change_ok(inode, &newattrs);
     if (!code) {
 #ifdef INODE_SETATTR_NOT_VOID
@@ -216,7 +215,6 @@ osi_UFSTruncate(register struct osi_file *afile, afs_int32 asize)
         inode_setattr(inode, &newattrs);
 #endif
     }
-    unlock_kernel();
     if (!code)
 	truncate_inode_pages(&inode->i_data, asize);
     code = -code;
diff --git a/src/afs/LINUX/osi_groups.c b/src/afs/LINUX/osi_groups.c
index f5a0bd2..1191cf2 100644
--- a/src/afs/LINUX/osi_groups.c
+++ b/src/afs/LINUX/osi_groups.c
@@ -272,24 +272,20 @@ afs_xsetgroups(int gidsetsize, gid_t * grouplist)
     afs_uint32 junk;
     int old_pag;
 
-    lock_kernel();
     old_pag = PagInCred(cr);
     crfree(cr);
-    unlock_kernel();
 
     code = (*sys_setgroupsp) (gidsetsize, grouplist);
     if (code) {
 	return code;
     }
 
-    lock_kernel();
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 	/* re-install old pag if there's room. */
 	code = __setpag(&cr, old_pag, &junk, 0);
     }
     crfree(cr);
-    unlock_kernel();
 
     /* Linux syscall ABI returns errno as negative */
     return (-code);
@@ -305,10 +301,8 @@ afs_xsetgroups32(int gidsetsize, gid_t * grouplist)
     afs_uint32 junk;
     int old_pag;
 
-    lock_kernel();
     old_pag = PagInCred(cr);
     crfree(cr);
-    unlock_kernel();
 
     code = (*sys_setgroups32p) (gidsetsize, grouplist);
 
@@ -316,14 +310,12 @@ afs_xsetgroups32(int gidsetsize, gid_t * grouplist)
 	return code;
     }
 
-    lock_kernel();
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 	/* re-install old pag if there's room. */
 	code = __setpag(&cr, old_pag, &junk, 0);
     }
     crfree(cr);
-    unlock_kernel();
 
     /* Linux syscall ABI returns errno as negative */
     return (-code);
@@ -339,24 +331,20 @@ asmlinkage long afs32_xsetgroups(int gidsetsize, gid_t *grouplist)
     afs_uint32 junk;
     int old_pag;
     
-    lock_kernel();
     old_pag = PagInCred(cr);
     crfree(cr);
-    unlock_kernel();
     
     code = (*sys32_setgroupsp)(gidsetsize, grouplist);
     if (code) {
 	return code;
     }
     
-    lock_kernel();
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 	/* re-install old pag if there's room. */
 	code = __setpag(&cr, old_pag, &junk, 0);
     }
     crfree(cr);
-    unlock_kernel();
     
     /* Linux syscall ABI returns errno as negative */
     return (-code);
@@ -374,24 +362,20 @@ afs32_xsetgroups(int gidsetsize, u16 * grouplist)
     afs_uint32 junk;
     int old_pag;
     
-    lock_kernel();
     old_pag = PagInCred(cr);
     crfree(cr);
-    unlock_kernel();
     
     code = (*sys32_setgroupsp) (gidsetsize, grouplist);
     if (code) {
 	return code;
     }
     
-    lock_kernel();
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 	/* re-install old pag if there's room. */
 	code = __setpag(&cr, old_pag, &junk, 0);
     }
     crfree(cr);
-    unlock_kernel();
     
     /* Linux syscall ABI returns errno as negative */
     return (-code);
@@ -407,24 +391,20 @@ afs32_xsetgroups32(int gidsetsize, gid_t * grouplist)
     afs_uint32 junk;
     int old_pag;
 
-    lock_kernel();
     old_pag = PagInCred(cr);
     crfree(cr);
-    unlock_kernel();
 
     code = (*sys32_setgroups32p) (gidsetsize, grouplist);
     if (code) {
 	return code;
     }
 
-    lock_kernel();
     cr = crref();
     if (old_pag != NOPAG && PagInCred(cr) == NOPAG) {
 	/* re-install old pag if there's room. */
 	code = __setpag(&cr, old_pag, &junk, 0);
     }
     crfree(cr);
-    unlock_kernel();
 
     /* Linux syscall ABI returns errno as negative */
     return (-code);
diff --git a/src/afs/LINUX/osi_vfsops.c b/src/afs/LINUX/osi_vfsops.c
index b7d1c1a..1d3406d 100644
--- a/src/afs/LINUX/osi_vfsops.c
+++ b/src/afs/LINUX/osi_vfsops.c
@@ -208,7 +208,6 @@ afs_notify_change(struct dentry *dp, struct iattr *iattrp)
     VATTR_NULL(&vattr);
     iattr2vattr(&vattr, iattrp);	/* Convert for AFS vnodeops call. */
 
-    lock_kernel();
     AFS_GLOCK();
     code = afs_setattr(VTOAFS(ip), &vattr, credp);
     if (!code) {
@@ -216,7 +215,6 @@ afs_notify_change(struct dentry *dp, struct iattr *iattrp)
 	vattr2inode(ip, &vattr);
     }
     AFS_GUNLOCK();
-    unlock_kernel();
     crfree(credp);
     return -code;
 }
diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 8c42134..0e18504 100644
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -53,21 +53,6 @@ extern struct backing_dev_info *afs_backing_dev_info;
 
 extern struct vcache *afs_globalVp;
 extern int afs_notify_change(struct dentry *dp, struct iattr *iattrp);
-/* Some uses of BKL are perhaps not needed for bypass or memcache--
- * why don't we try it out? */
-extern struct afs_cacheOps afs_UfsCacheOps;
-
-static inline void
-afs_maybe_lock_kernel(void) {
-    if(afs_cacheType == &afs_UfsCacheOps)
-        lock_kernel();
-}
-
-static inline void
-afs_maybe_unlock_kernel(void) {
-    if(afs_cacheType == &afs_UfsCacheOps)
-	unlock_kernel();
-}
 
 /* This function converts a positive error code from AFS into a negative
  * code suitable for passing into the Linux VFS layer. It checks that the
@@ -212,7 +197,6 @@ afs_linux_readdir(struct file *fp, void *dirbuf, filldir_t filldir)
     cred_t *credp = crref();
     struct afs_fakestat_state fakestat;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     AFS_STATCNT(afs_readdir);
 
@@ -364,7 +348,6 @@ out:
     afs_PutFakeStat(&fakestat);
 out1:
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
     return code;
 }
 
@@ -416,11 +399,9 @@ afs_linux_open(struct inode *ip, struct file *fp)
     cred_t *credp = crref();
     int code;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     code = afs_open(&vcp, fp->f_flags, credp);
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
 
     crfree(credp);
     return afs_convert_code(code);
@@ -433,7 +414,6 @@ afs_linux_release(struct inode *ip, struct file *fp)
     cred_t *credp = crref();
     int code = 0;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     code = afs_close(vcp, fp->f_flags, credp);
     ObtainWriteLock(&vcp->lock, 807);
@@ -443,7 +423,6 @@ afs_linux_release(struct inode *ip, struct file *fp)
     }
     ReleaseWriteLock(&vcp->lock);
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
 
     crfree(credp);
     return afs_convert_code(code);
@@ -460,11 +439,9 @@ afs_linux_fsync(struct file *fp, int datasync)
     struct inode *ip = FILE_INODE(fp);
     cred_t *credp = crref();
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     code = afs_fsync(VTOAFS(ip), credp);
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
     crfree(credp);
     return afs_convert_code(code);
 
@@ -781,7 +758,6 @@ afs_linux_revalidate(struct dentry *dp)
     if (afs_shuttingdown)
 	return EIO;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
 
 #ifdef notyet
@@ -792,7 +768,6 @@ afs_linux_revalidate(struct dentry *dp)
 	    check_bad_parent(dp);	/* check and correct mvid */
 
 	AFS_GUNLOCK();
-	unlock_kernel();
 	return 0;
     }
 #endif
@@ -814,7 +789,6 @@ afs_linux_revalidate(struct dentry *dp)
         afs_fill_inode(AFSTOV(vcp), &vattr);
 
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
 
     return afs_convert_code(code);
 }
@@ -850,7 +824,6 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
     int valid;
     struct afs_fakestat_state fakestate;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     afs_InitFakeStat(&fakestate);
 
@@ -963,7 +936,6 @@ afs_linux_dentry_revalidate(struct dentry *dp, int flags)
 	shrink_dcache_parent(dp);
 	d_drop(dp);
     }
-    afs_maybe_unlock_kernel();
     return valid;
 
   bad_dentry:
@@ -1034,7 +1006,6 @@ afs_linux_create(struct inode *dip, struct dentry *dp, int mode)
     vattr.va_mode = mode;
     vattr.va_type = mode & S_IFMT;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     code = afs_create(VTOAFS(dip), (char *)name, &vattr, NONEXCL, mode,
 		      &vcp, credp);
@@ -1051,7 +1022,6 @@ afs_linux_create(struct inode *dip, struct dentry *dp, int mode)
     }
     AFS_GUNLOCK();
 
-    afs_maybe_unlock_kernel();
     crfree(credp);
     return afs_convert_code(code);
 }
@@ -1072,7 +1042,6 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     struct dentry *newdp = NULL;
     int code;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     code = afs_lookup(VTOAFS(dip), (char *)comp, &vcp, credp);
     
@@ -1100,7 +1069,6 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
 		dput(alias);
 	    } else {
 		iput(ip);
-		afs_maybe_unlock_kernel();
 		crfree(credp);
 		return alias;
 	    }
@@ -1108,7 +1076,6 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     }
     newdp = d_splice_alias(ip, dp);
 
-    afs_maybe_unlock_kernel();
     crfree(credp);
 
     /* It's ok for the file to not be found. That's noted by the caller by
@@ -1212,8 +1179,6 @@ afs_linux_unlink(struct inode *dip, struct dentry *dp)
     const char *name = dp->d_name.name;
     struct vcache *tvc = VTOAFS(dp->d_inode);
 
-    afs_maybe_lock_kernel();
-
     if (VREFCOUNT(tvc) > 1 && tvc->opens > 0
 				&& !(tvc->f.states & CUnlinked)) {
 
@@ -1226,7 +1191,6 @@ afs_linux_unlink(struct inode *dip, struct dentry *dp)
 	    d_drop(dp);
     }
 
-    afs_maybe_unlock_kernel();
     crfree(credp);
     return afs_convert_code(code);
 }
@@ -1262,7 +1226,6 @@ afs_linux_mkdir(struct inode *dip, struct dentry *dp, int mode)
     struct vattr vattr;
     const char *name = dp->d_name.name;
 
-    afs_maybe_lock_kernel();
     VATTR_NULL(&vattr);
     vattr.va_mask = ATTR_MODE;
     vattr.va_mode = mode;
@@ -1281,7 +1244,6 @@ afs_linux_mkdir(struct inode *dip, struct dentry *dp, int mode)
     }
     AFS_GUNLOCK();
 
-    afs_maybe_unlock_kernel();
     crfree(credp);
     return afs_convert_code(code);
 }
@@ -1327,7 +1289,6 @@ afs_linux_rename(struct inode *oldip, struct dentry *olddp,
     struct dentry *rehash = NULL;
 
     /* Prevent any new references during rename operation. */
-    afs_maybe_lock_kernel();
 
     if (!d_unhashed(newdp)) {
 	d_drop(newdp);
@@ -1347,8 +1308,6 @@ afs_linux_rename(struct inode *oldip, struct dentry *olddp,
     if (rehash)
 	d_rehash(rehash);
 
-    afs_maybe_unlock_kernel();
-
     crfree(credp);
     return afs_convert_code(code);
 }
@@ -1664,7 +1623,6 @@ afs_linux_fillpage(struct file *fp, struct page *pp)
     setup_uio(auio, iovecp, (char *)address, offset, PAGE_SIZE, UIO_READ,
               AFS_UIOSYS);
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     AFS_DISCON_LOCK();
     afs_Trace4(afs_iclSetp, CM_TRACE_READPAGE, ICL_TYPE_POINTER, ip,
@@ -1678,7 +1636,6 @@ afs_linux_fillpage(struct file *fp, struct page *pp)
 	       code);
     AFS_DISCON_UNLOCK();
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
     if (!code) {
 	/* XXX valid for no-cache also?  Check last bits of files... :)
 	 * Cognate code goes in afs_NoCacheFetchProc.  */
@@ -1871,9 +1828,7 @@ afs_linux_bypass_readpage(struct file *fp, struct page *pp)
     ancr->length = PAGE_SIZE;
 
     credp = crref();
-    afs_maybe_lock_kernel();
     code = afs_ReadNoCache(VTOAFS(FILE_INODE(fp)), ancr, credp);
-    afs_maybe_unlock_kernel();
     crfree(credp);
 
     return afs_convert_code(code);
@@ -2085,7 +2040,6 @@ afs_linux_page_writeback(struct inode *ip, struct page *pp,
     buffer = kmap(pp) + offset;
     base = page_offset(pp) + offset;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     afs_Trace4(afs_iclSetp, CM_TRACE_UPDATEPAGE, ICL_TYPE_POINTER, vcp,
 	       ICL_TYPE_POINTER, pp, ICL_TYPE_INT32, page_count(pp),
@@ -2105,7 +2059,6 @@ afs_linux_page_writeback(struct inode *ip, struct page *pp,
 	       ICL_TYPE_INT32, code);
 
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
     kunmap(pp);
 
     return code;
@@ -2135,7 +2088,6 @@ afs_linux_writepage_sync(struct inode *ip, struct page *pp,
     credp = crref();
     code = afs_linux_page_writeback(ip, pp, offset, count, credp);
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     ObtainWriteLock(&vcp->lock, 533);
     if (code > 0)
@@ -2143,7 +2095,6 @@ afs_linux_writepage_sync(struct inode *ip, struct page *pp,
     afs_linux_complete_writeback(vcp);
     ReleaseWriteLock(&vcp->lock);
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
     crfree(credp);
 
     if (code1)
@@ -2224,7 +2175,6 @@ afs_linux_writepage(struct page *pp)
 
     code = afs_linux_page_writeback(inode, pp, 0, to, credp);
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     ObtainWriteLock(&vcp->lock, 538);
 
@@ -2240,7 +2190,6 @@ afs_linux_writepage(struct page *pp)
     ReleaseWriteLock(&vcp->lock);
     crfree(credp);
     AFS_GUNLOCK();
-    afs_maybe_unlock_kernel();
 
 done:
     end_page_writeback(pp);
@@ -2427,7 +2376,6 @@ afs_symlink_filler(struct file *file, struct page *page)
     char *p = (char *)kmap(page);
     int code;
 
-    afs_maybe_lock_kernel();
     AFS_GLOCK();
     code = afs_linux_ireadlink(ip, p, PAGE_SIZE, AFS_UIOSYS);
     AFS_GUNLOCK();
@@ -2435,7 +2383,6 @@ afs_symlink_filler(struct file *file, struct page *page)
     if (code < 0)
 	goto fail;
     p[code] = '\0';		/* null terminate? */
-    afs_maybe_unlock_kernel();
 
     SetPageUptodate(page);
     kunmap(page);
@@ -2443,8 +2390,6 @@ afs_symlink_filler(struct file *file, struct page *page)
     return 0;
 
   fail:
-    afs_maybe_unlock_kernel();
-
     SetPageError(page);
     kunmap(page);
     unlock_page(page);
diff --git a/src/afs/afs_syscall.c b/src/afs/afs_syscall.c
index b6425fa..d3496bf 100644
--- a/src/afs/afs_syscall.c
+++ b/src/afs/afs_syscall.c
@@ -595,7 +595,6 @@ Afs_syscall()
     }
 #endif
 #ifdef AFS_LINUX20_ENV
-    lock_kernel();
     /* setup uap for use below - pull out the magic decoder ring to know
      * which syscalls have folded argument lists.
      */
@@ -898,7 +897,6 @@ Afs_syscall()
 #endif
 #ifdef AFS_LINUX20_ENV
     code = -code;
-    unlock_kernel();
 #endif
     return code;
 }