mtd: nand: omap: fix race condition in omap_wait()

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=a9c465f07c2dcd515d20b96f93470762f9ae08b6
Commit:     a9c465f07c2dcd515d20b96f93470762f9ae08b6
Parent:     e25da1c07dfb318628a8a86f0967914dc4fd135e
Author:     Ivan Djelic <ivan.djelic at parrot.com>
AuthorDate: Tue Apr 17 13:11:53 2012 +0200
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Sun May 13 22:54:00 2012 -0500

    mtd: nand: omap: fix race condition in omap_wait()
    
    If a context switch occurs in function omap_wait() just before the
    while loop is entered, then upon return from context switch the
    timeout may already have elapsed: in that case, status is never
    read from NAND device, and omap_wait() returns an error.
    This failure has been experimentally observed during stress tests.
    
    This patch ensures a NAND status read is always performed before
    returning, as in the generic nand_wait() function.
    
    Signed-off-by: Ivan Djelic <ivan.djelic at parrot.com>
    Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at linux.intel.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/nand/omap2.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index ab56069..05d3562 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -881,7 +881,7 @@ static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
 	struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
 							mtd);
 	unsigned long timeo = jiffies;
-	int status = NAND_STATUS_FAIL, state = this->state;
+	int status, state = this->state;
 
 	if (state == FL_ERASING)
 		timeo += (HZ * 400) / 1000;
@@ -896,6 +896,8 @@ static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
 			break;
 		cond_resched();
 	}
+
+	status = gpmc_nand_read(info->gpmc_cs, GPMC_NAND_DATA);
 	return status;
 }