[PATCH] Decrease stack usage in ncpfs's ioctl

It decreases stack consumption in one of ncpfs's paths from 3000 to 2200
bytes (and stack portion in ncpfs ioctl code from 1336 to 452 bytes).

- some code used large structure (with embeded 256 bytes for filename)
  while it never passed filename around.  Use something smaller in
  ncp_conn_logged_in.  Decrease 616 => 300.

- gcc-3.3 is very bad when it comes to parallel blocks in ioctl.  Split
  some branches from large switch to separate functions.  ncp_ioctl now
  uses 152 bytes of stack (instead of 720) and biggest child 64.
Signed-off-by: Petr Vandrovec <vandrove@vc.cvut.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ncpfs/dir.c

@@ -762,12 +762,12 @@ ncp_do_readdir(struct file *filp, void *dirent, filldir_t filldir,
 int ncp_conn_logged_in(struct super_block *sb)
 {
 	struct ncp_server* server = NCP_SBP(sb);
-	struct nw_info_struct i;
 	int result;
 
 	if (ncp_single_volume(server)) {
 		int len;
 		struct dentry* dent;
+		__u32 volNumber, dirEntNum, DosDirNum;
 		__u8 __name[NCP_MAXPATHLEN + 1];
 
 		len = sizeof(__name);
@@ -776,7 +776,7 @@ int ncp_conn_logged_in(struct super_block *sb)
 		if (result)
 			goto out;
 		result = -ENOENT;
-		if (ncp_lookup_volume(server, __name, &i)) {
+		if (ncp_get_volume_root(server, __name, &volNumber, &dirEntNum, &DosDirNum)) {
 			PPRINTK("ncp_conn_logged_in: %s not found\n",
 				server->m.mounted_vol);
 			goto out;
@@ -785,9 +785,9 @@ int ncp_conn_logged_in(struct super_block *sb)
 		if (dent) {
 			struct inode* ino = dent->d_inode;
 			if (ino) {
-				NCP_FINFO(ino)->volNumber = i.volNumber;
-				NCP_FINFO(ino)->dirEntNum = i.dirEntNum;
-				NCP_FINFO(ino)->DosDirNum = i.DosDirNum;
+				NCP_FINFO(ino)->volNumber = volNumber;
+				NCP_FINFO(ino)->dirEntNum = dirEntNum;
+				NCP_FINFO(ino)->DosDirNum = DosDirNum;
 			} else {
 				DPRINTK("ncpfs: sb->s_root->d_inode == NULL!\n");
 			}

fs/ncpfs/ioctl.c

@@ -29,6 +29,155 @@
 /* maximum negotiable packet size */
 #define NCP_PACKET_SIZE_INTERNAL 65536
 
+static int
+ncp_get_fs_info(struct ncp_server* server, struct inode* inode, struct ncp_fs_info* arg)
+{
+	struct ncp_fs_info info;
+
+	if ((permission(inode, MAY_WRITE, NULL) != 0)
+	    && (current->uid != server->m.mounted_uid)) {
+		return -EACCES;
+	}
+	if (copy_from_user(&info, arg, sizeof(info)))
+		return -EFAULT;
+
+	if (info.version != NCP_GET_FS_INFO_VERSION) {
+		DPRINTK("info.version invalid: %d\n", info.version);
+		return -EINVAL;
+	}
+	/* TODO: info.addr = server->m.serv_addr; */
+	SET_UID(info.mounted_uid, server->m.mounted_uid);
+	info.connection		= server->connection;
+	info.buffer_size	= server->buffer_size;
+	info.volume_number	= NCP_FINFO(inode)->volNumber;
+	info.directory_id	= NCP_FINFO(inode)->DosDirNum;
+
+	if (copy_to_user(arg, &info, sizeof(info)))
+		return -EFAULT;
+	return 0;
+}
+
+static int
+ncp_get_fs_info_v2(struct ncp_server* server, struct inode* inode, struct ncp_fs_info_v2* arg)
+{
+	struct ncp_fs_info_v2 info2;
+
+	if ((permission(inode, MAY_WRITE, NULL) != 0)
+	    && (current->uid != server->m.mounted_uid)) {
+		return -EACCES;
+	}
+	if (copy_from_user(&info2, arg, sizeof(info2)))
+		return -EFAULT;
+
+	if (info2.version != NCP_GET_FS_INFO_VERSION_V2) {
+		DPRINTK("info.version invalid: %d\n", info2.version);
+		return -EINVAL;
+	}
+	info2.mounted_uid   = server->m.mounted_uid;
+	info2.connection    = server->connection;
+	info2.buffer_size   = server->buffer_size;
+	info2.volume_number = NCP_FINFO(inode)->volNumber;
+	info2.directory_id  = NCP_FINFO(inode)->DosDirNum;
+	info2.dummy1 = info2.dummy2 = info2.dummy3 = 0;
+
+	if (copy_to_user(arg, &info2, sizeof(info2)))
+		return -EFAULT;
+	return 0;
+}
+
+#ifdef CONFIG_NCPFS_NLS
+/* Here we are select the iocharset and the codepage for NLS.
+ * Thanks Petr Vandrovec for idea and many hints.
+ */
+static int
+ncp_set_charsets(struct ncp_server* server, struct ncp_nls_ioctl* arg)
+{
+	struct ncp_nls_ioctl user;
+	struct nls_table *codepage;
+	struct nls_table *iocharset;
+	struct nls_table *oldset_io;
+	struct nls_table *oldset_cp;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+	if (server->root_setuped)
+		return -EBUSY;
+
+	if (copy_from_user(&user, arg, sizeof(user)))
+		return -EFAULT;
+
+	codepage = NULL;
+	user.codepage[NCP_IOCSNAME_LEN] = 0;
+	if (!user.codepage[0] || !strcmp(user.codepage, "default"))
+		codepage = load_nls_default();
+	else {
+		codepage = load_nls(user.codepage);
+		if (!codepage) {
+			return -EBADRQC;
+		}
+	}
+
+	iocharset = NULL;
+	user.iocharset[NCP_IOCSNAME_LEN] = 0;
+	if (!user.iocharset[0] || !strcmp(user.iocharset, "default")) {
+		iocharset = load_nls_default();
+		NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
+	} else if (!strcmp(user.iocharset, "utf8")) {
+		iocharset = load_nls_default();
+		NCP_SET_FLAG(server, NCP_FLAG_UTF8);
+	} else {
+		iocharset = load_nls(user.iocharset);
+		if (!iocharset) {
+			unload_nls(codepage);
+			return -EBADRQC;
+		}
+		NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
+	}
+
+	oldset_cp = server->nls_vol;
+	server->nls_vol = codepage;
+	oldset_io = server->nls_io;
+	server->nls_io = iocharset;
+
+	if (oldset_cp)
+		unload_nls(oldset_cp);
+	if (oldset_io)
+		unload_nls(oldset_io);
+
+	return 0;
+}
+
+static int
+ncp_get_charsets(struct ncp_server* server, struct ncp_nls_ioctl* arg)
+{
+	struct ncp_nls_ioctl user;
+	int len;
+
+	memset(&user, 0, sizeof(user));
+	if (server->nls_vol && server->nls_vol->charset) {
+		len = strlen(server->nls_vol->charset);
+		if (len > NCP_IOCSNAME_LEN)
+			len = NCP_IOCSNAME_LEN;
+		strncpy(user.codepage, server->nls_vol->charset, len);
+		user.codepage[len] = 0;
+	}
+
+	if (NCP_IS_FLAG(server, NCP_FLAG_UTF8))
+		strcpy(user.iocharset, "utf8");
+	else if (server->nls_io && server->nls_io->charset) {
+		len = strlen(server->nls_io->charset);
+		if (len > NCP_IOCSNAME_LEN)
+			len = NCP_IOCSNAME_LEN;
+		strncpy(user.iocharset,	server->nls_io->charset, len);
+		user.iocharset[len] = 0;
+	}
+
+	if (copy_to_user(arg, &user, sizeof(user)))
+		return -EFAULT;
+	return 0;
+}
+#endif /* CONFIG_NCPFS_NLS */
+
 int ncp_ioctl(struct inode *inode, struct file *filp,
 	      unsigned int cmd, unsigned long arg)
 {
@@ -96,60 +245,10 @@ int ncp_ioctl(struct inode *inode, struct file *filp,
 		return ncp_conn_logged_in(inode->i_sb);
 
 	case NCP_IOC_GET_FS_INFO:
-		{
-			struct ncp_fs_info info;
-
-			if ((permission(inode, MAY_WRITE, NULL) != 0)
-			    && (current->uid != server->m.mounted_uid)) {
-				return -EACCES;
-			}
-			if (copy_from_user(&info, (struct ncp_fs_info *) arg, 
-				sizeof(info)))
-				return -EFAULT;
-
-			if (info.version != NCP_GET_FS_INFO_VERSION) {
-				DPRINTK("info.version invalid: %d\n", info.version);
-				return -EINVAL;
-			}
-			/* TODO: info.addr = server->m.serv_addr; */
-			SET_UID(info.mounted_uid, server->m.mounted_uid);
-			info.connection		= server->connection;
-			info.buffer_size	= server->buffer_size;
-			info.volume_number	= NCP_FINFO(inode)->volNumber;
-			info.directory_id	= NCP_FINFO(inode)->DosDirNum;
-
-			if (copy_to_user((struct ncp_fs_info *) arg, &info, 
-				sizeof(info))) return -EFAULT;
-			return 0;
-		}
+		return ncp_get_fs_info(server, inode, (struct ncp_fs_info *)arg);
 
 	case NCP_IOC_GET_FS_INFO_V2:
-		{
-			struct ncp_fs_info_v2 info2;
-
-			if ((permission(inode, MAY_WRITE, NULL) != 0)
-			    && (current->uid != server->m.mounted_uid)) {
-				return -EACCES;
-			}
-			if (copy_from_user(&info2, (struct ncp_fs_info_v2 *) arg, 
-				sizeof(info2)))
-				return -EFAULT;
-
-			if (info2.version != NCP_GET_FS_INFO_VERSION_V2) {
-				DPRINTK("info.version invalid: %d\n", info2.version);
-				return -EINVAL;
-			}
-			info2.mounted_uid   = server->m.mounted_uid;
-			info2.connection    = server->connection;
-			info2.buffer_size   = server->buffer_size;
-			info2.volume_number = NCP_FINFO(inode)->volNumber;
-			info2.directory_id  = NCP_FINFO(inode)->DosDirNum;
-			info2.dummy1 = info2.dummy2 = info2.dummy3 = 0;
-
-			if (copy_to_user((struct ncp_fs_info_v2 *) arg, &info2, 
-				sizeof(info2))) return -EFAULT;
-			return 0;
-		}
+		return ncp_get_fs_info_v2(server, inode, (struct ncp_fs_info_v2 *)arg);
 
 	case NCP_IOC_GETMOUNTUID2:
 		{
@@ -201,7 +300,7 @@ int ncp_ioctl(struct inode *inode, struct file *filp,
 	case NCP_IOC_SETROOT:
 		{
 			struct ncp_setroot_ioctl sr;
-			unsigned int vnum, de, dosde;
+			__u32 vnum, de, dosde;
 			struct dentry* dentry;
 
 			if (!capable(CAP_SYS_ADMIN))
@@ -219,15 +318,10 @@ int ncp_ioctl(struct inode *inode, struct file *filp,
 				dosde = 0;
 			} else if (sr.volNumber >= NCP_NUMBER_OF_VOLUMES) {
 				return -EINVAL;
-			} else {
-				struct nw_info_struct ni;
-				
-				if (ncp_mount_subdir(server, &ni, sr.volNumber,
-						sr.namespace, sr.dirEntNum))
-					return -ENOENT;
-				vnum = ni.volNumber;
-				de = ni.dirEntNum;
-				dosde = ni.DosDirNum;
+			} else if (ncp_mount_subdir(server, sr.volNumber,
+						sr.namespace, sr.dirEntNum,
+						&vnum, &de, &dosde)) {
+				return -ENOENT;
 			}
 			
 			dentry = inode->i_sb->s_root;
@@ -508,105 +602,14 @@ int ncp_ioctl(struct inode *inode, struct file *filp,
 		}
 
 #ifdef CONFIG_NCPFS_NLS
-/* Here we are select the iocharset and the codepage for NLS.
- * Thanks Petr Vandrovec for idea and many hints.
- */
 	case NCP_IOC_SETCHARSETS:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EACCES;
-		if (server->root_setuped)
-			return -EBUSY;
-
-		{
-			struct ncp_nls_ioctl user;
-			struct nls_table *codepage;
-			struct nls_table *iocharset;
-			struct nls_table *oldset_io;
-			struct nls_table *oldset_cp;
-			
-			if (copy_from_user(&user, (struct ncp_nls_ioctl*)arg,
-					sizeof(user)))
-				return -EFAULT;
-
-			codepage = NULL;
-			user.codepage[NCP_IOCSNAME_LEN] = 0;
-			if (!user.codepage[0] ||
-					!strcmp(user.codepage, "default"))
-				codepage = load_nls_default();
-			else {
-				codepage = load_nls(user.codepage);
-				if (!codepage) {
-					return -EBADRQC;
-				}
-			}
-
-			iocharset = NULL;
-			user.iocharset[NCP_IOCSNAME_LEN] = 0;
-			if (!user.iocharset[0] ||
-					!strcmp(user.iocharset, "default")) {
-				iocharset = load_nls_default();
-				NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
-			} else {
-				if (!strcmp(user.iocharset, "utf8")) {
-					iocharset = load_nls_default();
-					NCP_SET_FLAG(server, NCP_FLAG_UTF8);
-				} else {
-					iocharset = load_nls(user.iocharset);
-					if (!iocharset) {
-						unload_nls(codepage);
-						return -EBADRQC;
-					}
-					NCP_CLR_FLAG(server, NCP_FLAG_UTF8);
-				}
-			}
-
-			oldset_cp = server->nls_vol;
-			server->nls_vol = codepage;
-			oldset_io = server->nls_io;
-			server->nls_io = iocharset;
-
-			if (oldset_cp)
-				unload_nls(oldset_cp);
-			if (oldset_io)
-				unload_nls(oldset_io);
-
-			return 0;
-		}
+		return ncp_set_charsets(server, (struct ncp_nls_ioctl *)arg);
 		
-	case NCP_IOC_GETCHARSETS: /* not tested */
-		{
-			struct ncp_nls_ioctl user;
-			int len;
-
-			memset(&user, 0, sizeof(user));
-			if (server->nls_vol && server->nls_vol->charset) {
-				len = strlen(server->nls_vol->charset);
-				if (len > NCP_IOCSNAME_LEN)
-					len = NCP_IOCSNAME_LEN;
-				strncpy(user.codepage,
-						server->nls_vol->charset, len);
-				user.codepage[len] = 0;
-			}
-
-			if (NCP_IS_FLAG(server, NCP_FLAG_UTF8))
-				strcpy(user.iocharset, "utf8");
-			else
-				if (server->nls_io && server->nls_io->charset) {
-					len = strlen(server->nls_io->charset);
-					if (len > NCP_IOCSNAME_LEN)
-						len = NCP_IOCSNAME_LEN;
-					strncpy(user.iocharset,
-						server->nls_io->charset, len);
-					user.iocharset[len] = 0;
-				}
+	case NCP_IOC_GETCHARSETS:
+		return ncp_get_charsets(server, (struct ncp_nls_ioctl *)arg);
 
-			if (copy_to_user((struct ncp_nls_ioctl*)arg, &user,
-					sizeof(user)))
-				return -EFAULT;
-
-			return 0;
-		}
 #endif /* CONFIG_NCPFS_NLS */
+
 	case NCP_IOC_SETDENTRYTTL:
 		if ((permission(inode, MAY_WRITE, NULL) != 0) &&
 				 (current->uid != server->m.mounted_uid))

fs/ncpfs/ncplib_kernel.c

@@ -536,37 +536,34 @@ ncp_ObtainSpecificDirBase(struct ncp_server *server,
 }
 
 int
-ncp_mount_subdir(struct ncp_server *server, struct nw_info_struct *i,
-			__u8 volNumber, __u8 srcNS, __u32 dirEntNum)
+ncp_mount_subdir(struct ncp_server *server,
+		 __u8 volNumber, __u8 srcNS, __u32 dirEntNum,
+		 __u32* volume, __u32* newDirEnt, __u32* newDosEnt)
 {
 	int dstNS;
 	int result;
-	__u32 newDirEnt;
-	__u32 newDosEnt;
 	
 	dstNS = ncp_get_known_namespace(server, volNumber);
 	if ((result = ncp_ObtainSpecificDirBase(server, srcNS, dstNS, volNumber, 
-				      dirEntNum, NULL, &newDirEnt, &newDosEnt)) != 0)
+				      dirEntNum, NULL, newDirEnt, newDosEnt)) != 0)
 	{
 		return result;
 	}
 	server->name_space[volNumber] = dstNS;
-	i->volNumber = volNumber;
-	i->dirEntNum = newDirEnt;
-	i->DosDirNum = newDosEnt;
+	*volume = volNumber;
 	server->m.mounted_vol[1] = 0;
 	server->m.mounted_vol[0] = 'X';
 	return 0;
 }
 
 int 
-ncp_lookup_volume(struct ncp_server *server, char *volname,
-		      struct nw_info_struct *target)
+ncp_get_volume_root(struct ncp_server *server, const char *volname,
+		    __u32* volume, __u32* dirent, __u32* dosdirent)
 {
 	int result;
-	int volnum;
+	__u8 volnum;
 
-	DPRINTK("ncp_lookup_volume: looking up vol %s\n", volname);
+	DPRINTK("ncp_get_volume_root: looking up vol %s\n", volname);
 
 	ncp_init_request(server);
 	ncp_add_byte(server, 22);	/* Subfunction: Generate dir handle */
@@ -585,16 +582,31 @@ ncp_lookup_volume(struct ncp_server *server, char *volname,
 		ncp_unlock_server(server);
 		return result;
 	}
-	memset(target, 0, sizeof(*target));
-	target->DosDirNum = target->dirEntNum = ncp_reply_dword(server, 4);
-	target->volNumber = volnum = ncp_reply_byte(server, 8);
+	*dirent = *dosdirent = ncp_reply_dword(server, 4);
+	volnum = ncp_reply_byte(server, 8);
 	ncp_unlock_server(server);
+	*volume = volnum;
 
 	server->name_space[volnum] = ncp_get_known_namespace(server, volnum);
 
 	DPRINTK("lookup_vol: namespace[%d] = %d\n",
 		volnum, server->name_space[volnum]);
 
+	return 0;
+}
+
+int
+ncp_lookup_volume(struct ncp_server *server, const char *volname,
+		  struct nw_info_struct *target)
+{
+	int result;
+
+	memset(target, 0, sizeof(*target));
+	result = ncp_get_volume_root(server, volname,
+			&target->volNumber, &target->dirEntNum, &target->DosDirNum);
+	if (result) {
+		return result;
+	}
 	target->nameLen = strlen(volname);
 	memcpy(target->entryName, volname, target->nameLen+1);
 	target->attributes = aDIR;

fs/ncpfs/ncplib_kernel.h

@@ -70,7 +70,9 @@ void ncp_extract_file_info(void* src, struct nw_info_struct* target);
 int ncp_obtain_info(struct ncp_server *server, struct inode *, char *,
 		struct nw_info_struct *target);
 int ncp_obtain_nfs_info(struct ncp_server *server, struct nw_info_struct *target);
-int ncp_lookup_volume(struct ncp_server *, char *, struct nw_info_struct *);
+int ncp_get_volume_root(struct ncp_server *server, const char *volname,
+			__u32 *volume, __u32 *dirent, __u32 *dosdirent);
+int ncp_lookup_volume(struct ncp_server *, const char *, struct nw_info_struct *);
 int ncp_modify_file_or_subdir_dos_info(struct ncp_server *, struct inode *,
 	 __u32, const struct nw_modify_dos_info *info);
 int ncp_modify_file_or_subdir_dos_info_path(struct ncp_server *, struct inode *,
@@ -111,8 +113,8 @@ ncp_ClearPhysicalRecord(struct ncp_server *server,
 #endif	/* CONFIG_NCPFS_IOCTL_LOCKING */
 
 int
-ncp_mount_subdir(struct ncp_server *, struct nw_info_struct *,
-			__u8, __u8, __u32);
+ncp_mount_subdir(struct ncp_server *, __u8, __u8, __u32,
+		 __u32* volume, __u32* dirent, __u32* dosdirent);
 int ncp_dirhandle_alloc(struct ncp_server *, __u8 vol, __u32 dirent, __u8 *dirhandle);
 int ncp_dirhandle_free(struct ncp_server *, __u8 dirhandle);