[PATCH] nvme: invalidate correct memory range after read

[Andre Przywara]

On Tue, 28 Sep 2021 10:01:40 +0200
Stefan Agner <stefan at agner.ch> wrote:

> The current code invalidates the range after the read buffer since the
> buffer pointer gets incremented in the read loop. Use a temporary
> pointer to make sure we have a pristine pointer to invalidate the
> correct memory range after read.

Ah, good catch!
This looks good, just one nit below:

> Fixes: 704e040a51d2 ("nvme: Apply cache operations on the DMA buffers")
> Signed-off-by: Stefan Agner <stefan at agner.ch>
> ---
> 
>  drivers/nvme/nvme.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c
> index f6465ea7f4..354513ad30 100644
> --- a/drivers/nvme/nvme.c
> +++ b/drivers/nvme/nvme.c
> @@ -743,6 +743,7 @@ static ulong nvme_blk_rw(struct udevice *udev, lbaint_t blknr,
>  	u64 prp2;
>  	u64 total_len = blkcnt << desc->log2blksz;
>  	u64 temp_len = total_len;
> +	void *temp_buffer = buffer;

You could make this an unsigned long (or better uintptr_t), then lose all
the casts below and avoid the void ptr arithmetic.

But it works either way, so:

Reviewed-by: Andre Przywara <andre.przywara at arm.com>

Cheers,
Andre


>  
>  	u64 slba = blknr;
>  	u16 lbas = 1 << (dev->max_transfer_shift - ns->lba_shift);
> @@ -770,19 +771,19 @@ static ulong nvme_blk_rw(struct udevice *udev, lbaint_t blknr,
>  		}
>  
>  		if (nvme_setup_prps(dev, &prp2,
> -				    lbas << ns->lba_shift, (ulong)buffer))
> +				    lbas << ns->lba_shift, (ulong)temp_buffer))
>  			return -EIO;
>  		c.rw.slba = cpu_to_le64(slba);
>  		slba += lbas;
>  		c.rw.length = cpu_to_le16(lbas - 1);
> -		c.rw.prp1 = cpu_to_le64((ulong)buffer);
> +		c.rw.prp1 = cpu_to_le64((ulong)temp_buffer);
>  		c.rw.prp2 = cpu_to_le64(prp2);
>  		status = nvme_submit_sync_cmd(dev->queues[NVME_IO_Q],
>  				&c, NULL, IO_TIMEOUT);
>  		if (status)
>  			break;
>  		temp_len -= (u32)lbas << ns->lba_shift;
> -		buffer += lbas << ns->lba_shift;
> +		temp_buffer += lbas << ns->lba_shift;
>  	}
>  
>  	if (read)