forked from Minki/linux
mtd: check for max_bitflips in mtd_read_oob()
mtd_read_oob() has some unexpected similarities to mtd_read(). For instance, when ops->datbuf != NULL, nand_base.c might return max_bitflips; however, when ops->datbuf == NULL, nand_base's code potentially could return -EUCLEAN (no in-tree drivers do this yet). In any case where the driver might return max_bitflips, we should translate this into an appropriate return code using the bitflip_threshold. Essentially, mtd_read_oob() duplicates the logic from mtd_read(). This prevents users of mtd_read_oob() from receiving a positive return value (i.e., from max_bitflips) and interpreting it as an unknown error. Artem: amend comments. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Reviewed-by: Mike Dunn <mikedunn@newsguy.com> Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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@ -860,10 +860,22 @@ EXPORT_SYMBOL_GPL(mtd_panic_write);
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int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
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{
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int ret_code;
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ops->retlen = ops->oobretlen = 0;
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if (!mtd->_read_oob)
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return -EOPNOTSUPP;
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return mtd->_read_oob(mtd, from, ops);
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/*
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* In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics
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* similar to mtd->_read(), returning a non-negative integer
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* representing max bitflips. In other cases, mtd->_read_oob() may
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* return -EUCLEAN. In all cases, perform similar logic to mtd_read().
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*/
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ret_code = mtd->_read_oob(mtd, from, ops);
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if (unlikely(ret_code < 0))
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return ret_code;
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if (mtd->ecc_strength == 0)
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return 0; /* device lacks ecc */
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return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
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}
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EXPORT_SYMBOL_GPL(mtd_read_oob);
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