Re: [PATCH] libata: fix ata_id_logical_per_physical_sectors

[Sergei Shtylyov <sshtylyov@ru.mvista.com>]

Hello.

Christoph Hellwig wrote:

> The value we get from the low byte of the ATA_ID_SECTOR_SIZE word is not not
> a plain multiple, but the log of it, so fix the helper to give the correct
> answer.  Without this we'll get an incorrect minimal I/O size in the block
> limits VPD page for 4k sector drives.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Index: linux-2.6/include/linux/ata.h
> ===================================================================
> --- linux-2.6.orig/include/linux/ata.h	2010-01-28 11:17:41.968003842 +0100
> +++ linux-2.6/include/linux/ata.h	2010-01-28 11:20:02.355268610 +0100
> @@ -649,7 +649,7 @@ static inline int ata_id_has_large_logic
>  
>  static inline u8 ata_id_logical_per_physical_sectors(const u16 *id)
>  {
> -	return id[ATA_ID_SECTOR_SIZE] & 0xf;
> +	return 1 << (id[ATA_ID_SECTOR_SIZE] & 0xf);
>   

   Will this still fit into u8?

WBR, Sergei