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From: Peter Grayson <pgrayson@realmsys.com>
To: linux-mtd@lists.infradead.org
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Date: Fri, 23 Sep 2005 17:29:14 -0600
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Subject: [PATCH] nandbase performance
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Here is a patch against nand_base.c that improves partial page read
performance. The patch simply replaces a byte-by-byte copy in a for-loop
with a memcpy() call. Jffs2 does a lot of these partial page reads.

Pete

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diff -uNr mtd/drivers/mtd/nand/nand_base.c mtd-nandbase/drivers/mtd/nand/nand_base.c
--- mtd/drivers/mtd/nand/nand_base.c	2005-09-16 15:30:32.000000000 -0600
+++ mtd-nandbase/drivers/mtd/nand/nand_base.c	2005-09-23 17:21:38.032055488 -0600
@@ -1311,8 +1311,9 @@
 	readdata:
 		/* Partial page read, transfer data into fs buffer */
 		if (!aligned) { 
-			for (j = col; j < end && read < len; j++)
-				buf[read++] = data_poi[j];
+			int bytes_to_copy = min(end - col, (int)len - read);
+			memcpy(&buf[read], &data_poi[col], bytes_to_copy);
+			read += bytes_to_copy;
 			this->pagebuf = realpage;	
 		} else		
 			read += mtd->oobblock;

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