Re: 2.6.6-rc3-mm2 (4KSTACK)

[Andrew Morton]

"Martin J. Bligh" <mbligh@xxxxxxxxxxx> wrote:
>
> 2 nfs_writepage_sync is a known stack-abuser ;-) 1632 bytes on PPC64 at least
>  (from Anton's data). Maybe it's that struct nfs_write_data ?

 (from Anton's data). Maybe it's that struct nfs_write_data ?


diff -puN fs/nfs/write.c~nfs_writepage_sync-stack-reduction fs/nfs/write.c
--- 25/fs/nfs/write.c~nfs_writepage_sync-stack-reduction	2004-05-07 12:36:51.648098192 -0700
+++ 25-akpm/fs/nfs/write.c	2004-05-07 12:39:41.320304096 -0700
@@ -179,7 +179,13 @@ static int nfs_writepage_sync(struct fil
 {
 	unsigned int	wsize = NFS_SERVER(inode)->wsize;
 	int		result, written = 0;
-	struct nfs_write_data	wdata = {
+	struct nfs_write_data *wdata;
+
+	wdata = kmalloc(sizeof(*wdata), GFP_NOFS);
+	if (!wdata)
+		return -ENOMEM;
+
+	*wdata = (struct nfs_write_data) {
 		.flags		= how,
 		.cred		= NULL,
 		.inode		= inode,
@@ -192,8 +198,8 @@ static int nfs_writepage_sync(struct fil
 			.count		= wsize,
 		},
 		.res		= {
-			.fattr		= &wdata.fattr,
-			.verf		= &wdata.verf,
+			.fattr		= &wdata->fattr,
+			.verf		= &wdata->verf,
 		},
 	};
 
@@ -205,22 +211,22 @@ static int nfs_writepage_sync(struct fil
 	nfs_begin_data_update(inode);
 	do {
 		if (count < wsize)
-			wdata.args.count = count;
-		wdata.args.offset = page_offset(page) + wdata.args.pgbase;
+			wdata->args.count = count;
+		wdata->args.offset = page_offset(page) + wdata->args.pgbase;
 
-		result = NFS_PROTO(inode)->write(&wdata, file);
+		result = NFS_PROTO(inode)->write(wdata, file);
 
 		if (result < 0) {
 			/* Must mark the page invalid after I/O error */
 			ClearPageUptodate(page);
 			goto io_error;
 		}
-		if (result < wdata.args.count)
+		if (result < wdata->args.count)
 			printk(KERN_WARNING "NFS: short write, count=%u, result=%d\n",
-					wdata.args.count, result);
+					wdata->args.count, result);
 
-		wdata.args.offset += result;
-	        wdata.args.pgbase += result;
+		wdata->args.offset += result;
+	        wdata->args.pgbase += result;
 		written += result;
 		count -= result;
 	} while (count);
@@ -234,9 +240,10 @@ static int nfs_writepage_sync(struct fil
 
 io_error:
 	nfs_end_data_update_defer(inode);
-	if (wdata.cred)
-		put_rpccred(wdata.cred);
+	if (wdata->cred)
+		put_rpccred(wdata->cred);
 
+	kfree(wdata);
 	return written ? written : result;
 }
 

_

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