Commit a9c465f0 authored Apr 17, 2012 by Ivan Djelic Committed by David Woodhouse May 13, 2012

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@parrot.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

parent e25da1c0

drivers/mtd/nand/omap2.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}