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

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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>
This commit is contained in:
Ivan Djelic 2012-04-17 13:11:53 +02:00 committed by David Woodhouse
parent e25da1c07d
commit a9c465f07c
1 changed files with 3 additions and 1 deletions
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4
drivers/mtd/nand/omap2.c
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@ -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, struct omap_nand_info *info = container_of(mtd, struct omap_nand_info,
mtd); mtd);
unsigned long timeo = jiffies; unsigned long timeo = jiffies;
int status = NAND_STATUS_FAIL, state = this->state; int status, state = this->state;
if (state == FL_ERASING) if (state == FL_ERASING)
timeo += (HZ * 400) / 1000; timeo += (HZ * 400) / 1000;
@ -896,6 +896,8 @@ static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip)
break; break;
cond_resched(); cond_resched();
} }
status = gpmc_nand_read(info->gpmc_cs, GPMC_NAND_DATA);
return status; return status;
} }