On 24 August 2016 at 09:58, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> packed should always exist without calling its cleanup function
> explicitly. Moreover, we have use it when preparing packed list.
> So I don't believe we should ever fall into this check again when
> doing mmc_blk_packed_hdr_wrq_prep or mmc_blk_end_packed_req. And
> the code of mmc_blk_end_packed_req is trying to use packed before
> checking it which makes it quite weird. This patch is trying to
> remove these two checks and move it to the mmc_blk_prep_packed_list.
> If we find packed is null, then we should never use MMC_PACKED_NONE
> and MMC_BLK_PACKED_CMD. By doing this, we could fall back to
> non-packed request if finding null packed, though it's impossible
> theoretically.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
>
> ---
>
> Changes in v2:
> - remove BUG_ON and add fallback for packed instead of
> panic it.
>
> drivers/mmc/card/block.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 48a5dd7..c7a9b28 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -1673,6 +1673,18 @@ static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
> u8 max_packed_rw = 0;
> u8 reqs = 0;
>
> + /*
> + * We don't need to check packed for any further
> + * operation of packed stuff as we set MMC_PACKED_NONE
> + * and return zero for reqs if geting null packed. Also
> + * we clean the flag of MMC_BLK_PACKED_CMD to avoid doing
> + * it again when removing blk req.
> + */
> + if (!mqrq->packed) {
> + md->flags &= (~MMC_BLK_PACKED_CMD);
> + goto no_packed;
> + }
> +
> if (!(md->flags & MMC_BLK_PACKED_CMD))
> goto no_packed;
>
> @@ -1781,8 +1793,6 @@ static void mmc_blk_packed_hdr_wrq_prep(struct mmc_queue_req *mqrq,
> u8 hdr_blocks;
> u8 i = 1;
>
> - BUG_ON(!packed);
> -
> mqrq->cmd_type = MMC_PACKED_WRITE;
> packed->blocks = 0;
> packed->idx_failure = MMC_PACKED_NR_IDX;
> @@ -1886,8 +1896,6 @@ static int mmc_blk_end_packed_req(struct mmc_queue_req *mq_rq)
> int idx = packed->idx_failure, i = 0;
> int ret = 0;
>
> - BUG_ON(!packed);
> -
> while (!list_empty(&packed->list)) {
> prq = list_entry_rq(packed->list.next);
> if (idx == i) {
> --
> 2.3.7
>
>
This is step in the right direction, although there are still some
BUG_ONs() for the packed command path. Could you please have look and
remove all of them?
Kind regards
Uffe
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