[CIFS] Reduce cifs stack space usage

The two cifs functions that used the most stack according
to "make checkstack" have been changed to use less stack.

Thanks to jra and Shaggy for helpful ideas

Signed-off-by: Steve French <sfrench@us.ibm.com>
cc: jra@samba.org
cc: shaggy@us.ibm.com

2 files changed, 16 insertions, 4 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 8a49b2e..e9dcf5e 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1146,7 +1146,7 @@ static int cifs_writepages(struct address_space *mapping,
 	pgoff_t end;
 	pgoff_t index;
  	int range_whole = 0;
-	struct kvec iov[32];
+	struct kvec * iov;
 	int len;
 	int n_iov = 0;
 	pgoff_t next;
@@ -1171,15 +1171,21 @@ static int cifs_writepages(struct address_space *mapping,
 	if((cifs_sb->tcon->ses) && (cifs_sb->tcon->ses->server))
 		if(cifs_sb->tcon->ses->server->secMode &
                           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
-			if(!experimEnabled)
+			if(!experimEnabled) 
 				return generic_writepages(mapping, wbc);
 
+	iov = kmalloc(32 * sizeof(struct kvec), GFP_KERNEL);
+	if(iov == NULL)
+		return generic_writepages(mapping, wbc);
+
+
 	/*
 	 * BB: Is this meaningful for a non-block-device file system?
 	 * If it is, we should test it again after we do I/O
 	 */
 	if (wbc->nonblocking && bdi_write_congested(bdi)) {
 		wbc->encountered_congestion = 1;
+		kfree(iov);
 		return 0;
 	}
 
@@ -1345,7 +1351,7 @@ retry:
 		mapping->writeback_index = index;
 
 	FreeXid(xid);
-
+	kfree(iov);
 	return rc;
 }
 
diff --git a/fs/cifs/smbdes.c b/fs/cifs/smbdes.c
index 7a1b2b9..1a4a395 100644
--- a/fs/cifs/smbdes.c
+++ b/fs/cifs/smbdes.c
@@ -196,7 +196,7 @@ dohash(char *out, char *in, char *key, int forw)
 	char c[28];
 	char d[28];
 	char *cd;
-	char ki[16][48];
+	char (*ki)[48];
 	char *pd1;
 	char l[32], r[32];
 	char *rl;
@@ -206,6 +206,10 @@ dohash(char *out, char *in, char *key, int forw)
 	if(pk1 == NULL)
 		return;
 
+	ki = kmalloc(16*48, GFP_KERNEL);
+	if(ki == NULL)
+		return;
+
 	cd = pk1 + 56;
 	pd1= cd  + 56;
 	rl = pd1 + 64;
@@ -243,6 +247,7 @@ dohash(char *out, char *in, char *key, int forw)
 		er = kmalloc(48+48+32+32+32, GFP_KERNEL);
 		if(er == NULL) {
 			kfree(pk1);
+			kfree(ki);
 			return;
 		}
 		erk = er+48;
@@ -290,6 +295,7 @@ dohash(char *out, char *in, char *key, int forw)
 
 	permute(out, rl, perm6, 64);
 	kfree(pk1);
+	kfree(ki);
 }
 
 static void