From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Date: Sun, 21 Mar 2010 21:52:23 +0000 (+0100)
Subject: libata: don't flush dcache on slab pages
X-Git-Tag: firefly_0821_release~10186^2~1569
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8b867c02502f86a737e2ec747b0ef15ad93dc6e2;p=firefly-linux-kernel-4.4.55.git

libata: don't flush dcache on slab pages

commit 3842e835490cdf17013b30a788f6311bdcfd0571 upstream.

page_mapping() check this via VM_BUG_ON(PageSlab(page)) so we bug here
with the according debuging turned on.

Future TODO: replace this with a flush_dcache_page_for_pio() API

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 2ae15c3b22a7..776a89599448 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -893,7 +893,7 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 				       do_write);
 	}
 
-	if (!do_write)
+	if (!do_write && !PageSlab(page))
 		flush_dcache_page(page);
 
 	qc->curbytes += qc->sect_size;