tree af34201ba3bfc195a22ceac43a1c22f2f7c2fbe8
parent ff877ea80efa2015b6263766f78ee42c2a1b32f9
author Alexey Korolev <akorolev@infradead.org> 1210868598 +0100
committer David Woodhouse <David.Woodhouse@intel.com> 1216997390 -0400

[MTD] [NAND] subpage read feature as a way to increase performance. 

This patch enables NAND subpage read functionality.
If upper layer drivers are requesting to read non page aligned data NAND
subpage-read functionality reads the only whose ECC regions which include
requested data when original code reads whole page.
This significantly improves performance in many cases.

Here are some digits :

UBI volume mount time
No subpage reads: 5.75 seconds
Subpage read patch: 2.42 seconds

Open/stat time for files on JFFS2 volume:
No subpage read  0m 5.36s
Subpage read     0m 2.88s

Signed-off-by Alexey Korolev <akorolev@infradead.org>
Acked-by: Artem Bityutskiy <dedekind@infradead.org>
Acked-by: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>