jffs2 & new linux zlib

Clive Davies cdavies at altera.com
Tue Feb 19 09:24:30 EST 2002


In testing jffs2 in linux 2.5.4-rmk1 I've found that kmalloc cannot allocate 
objects of the size returned by zlib_deflate_workspacesize() and 
zlib_inflate_workspacesize(). The patch below uses vmalloc to sucessfully 
allocate the memory, however I'm not sure that this is the best approach., 
maybe it would be better to try and reduce the size of the deflate_workspace 
& inflate workspace in zlib? (This might be a ridiculous idea, I haven't a 
clue how zlib works) Any suggestions?

--- linux_2.5.4-rmk1/fs/jffs2/compr_zlib.c	Mon Feb 11 01:50:06 2002
+++ linux/fs/jffs2/compr_zlib.c	Tue Feb 19 13:33:24 2002
@@ -80,8 +80,7 @@ int zlib_compress(unsigned char *data_in
 		return -1;
 
 #ifdef __KERNEL__
-	strm.workspace = kmalloc(zlib_deflate_workspacesize(),
-				 GFP_KERNEL);
+	strm.workspace = vmalloc(zlib_deflate_workspacesize());
 	if (strm.workspace == NULL) {
 		printk(KERN_WARNING "deflateInit alloc of workspace failed\n");
 		return -1;
@@ -123,7 +122,7 @@ int zlib_compress(unsigned char *data_in
 
 	}
 	zlib_deflateEnd(&strm);
-	kfree(strm.workspace);
+	vfree(strm.workspace);
 
 	D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n", strm.total_in, 
strm.total_out));
 
@@ -137,7 +136,7 @@ int zlib_compress(unsigned char *data_in
 
  out_err:
 	zlib_deflateEnd(&strm);
-	kfree(strm.workspace);
+	vfree(strm.workspace);
 	return -1;
 }
 
@@ -148,8 +147,7 @@ void zlib_decompress(unsigned char *data
 	int ret;
 
 #ifdef __KERNEL__
-	strm.workspace = kmalloc(zlib_inflate_workspacesize(),
-				 GFP_KERNEL);
+	strm.workspace = vmalloc(zlib_inflate_workspacesize());
 	if (strm.workspace == NULL) {
 		printk(KERN_WARNING "inflateInit alloc of workspace failed\n");
 		return;
@@ -177,5 +175,5 @@ void zlib_decompress(unsigned char *data
 		printk(KERN_NOTICE "inflate returned %d\n", ret);
 	}
 	zlib_inflateEnd(&strm);
-	kfree(strm.workspace);
+	vfree(strm.workspace);
 }




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