On 01/12/15 10:41, Jonas Gorski wrote: > On Sat, Nov 28, 2015 at 8:23 PM, Simon Arlott <[email protected]> wrote: >> + >> + /* Go to start of buffer */ >> + buf -= FC_WORDS; >> + >> + /* Erased if all data bytes are 0xFF */ >> + buf_erased = memchr_inv(buf, 0xFF, FC_WORDS) == NULL; >> + >> + if (!buf_erased) >> + goto out_free; > > We now have a function exactly for that use case in 4.4, > nand_check_erased_buf [1], consider using that. This also has the > benefit of treating bit flips as correctable as long as the ECC scheme > is strong enough.
I have no idea whether or not it's appropriate to specify bitflips_threshold > 0 so it'd just be a more complex way to do a memchr_inv() search for 0xFF. The code also has to check for the hamming code bytes being all 0x00, because according to the comments [2], the controller also has difficulty with the non-erased all-0xFFs scenario too. [2] https://github.com/lp0/bcm963xx_4.12L.06B_consumer/blob/dd8fcb13046f738c311507dc2fcfd3e5d57a88e0/kernel/linux/drivers/mtd/brcmnand/brcmnand_base.c#L2459 > > Jonas > > [1] > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/mtd/nand/nand_base.c#n1110 > -- Simon Arlott -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
