Re: [PATCH v4 5/7] ata: libata: Fix FUA handling in ata_build_rw_tf()

[Hannes Reinecke <hare@suse.de>]

On 10/31/22 02:53, Damien Le Moal wrote:
> If a user issues a write command with the FUA bit set for a device with
> NCQ support disabled (that is, the device queue depth was set to 1), the
> LBA 48 command WRITE DMA FUA EXT must be used. However,
> ata_build_rw_tf() ignores this and first tests if LBA 28 can be used
> based on the write command sector and number of blocks. That is, for
> small FUA writes at low LBAs, ata_rwcmd_protocol() will cause the write
> to fail.
> 
> Fix this by preventing the use of LBA 28 for any FUA write request.
> 
> Given that the WRITE MULTI FUA EXT command is marked as obsolete iin the
> ATA specification since ACS-3 (published in 2013), remove the
> ATA_CMD_WRITE_MULTI_FUA_EXT command from the ata_rw_cmds array.
> 
> Finally, since the block layer should never issue a FUA read
> request, warn in ata_build_rw_tf() if we see such request.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> ---
>   drivers/ata/libata-core.c | 12 +++++++++---
>   1 file changed, 9 insertions(+), 3 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
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