RE: [PATCH RFC 2/4] ufs: Remove a check from ufshcd_queuecommand()

[Avri Altman <Avri.Altman@wdc.com>]

> scsi_add_host() allocates shost->can_queue tags. ufshcd_init() sets
> shost->can_queue to hba->nutrs. In other words, we know that tag values
> will be in the range [0, hba->nutrs). Remove a check that verifies what
> we already know. This check was introduced by commit 14497328b6a6
> ("scsi:
> ufs: verify command tag validity").
> 
> Cc: Gilad Broner <gbroner@codeaurora.org>
> Cc: Yaniv Gardi <ygardi@codeaurora.org>
> Cc: Subhash Jadavani <subhashj@codeaurora.org>
> Cc: Dolev Raviv <draviv@codeaurora.org>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  drivers/scsi/ufs/ufshcd.c | 14 ++------------
>  1 file changed, 2 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index c230d2a6a55c..71c720d940a3 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -2701,21 +2701,11 @@ static void ufshcd_init_lrb(struct ufs_hba *hba,
> struct ufshcd_lrb *lrb, int i)
>   */
>  static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd
> *cmd)
>  {
> +       struct ufs_hba *hba = shost_priv(host);
> +       int tag = cmd->request->tag;
>         struct ufshcd_lrb *lrbp;
> -       struct ufs_hba *hba;
> -       int tag;
>         int err = 0;
> 
> -       hba = shost_priv(host);
> -
> -       tag = cmd->request->tag;
> -       if (!ufshcd_valid_tag(hba, tag)) {
> -               dev_err(hba->dev,
> -                       "%s: invalid command tag %d: cmd=0x%p, cmd-
> >request=0x%p",
> -                       __func__, tag, cmd, cmd->request);
> -               BUG();
> -       }
While at it, maybe remove ufshcd_valid_tag altogether?

Thanks,
Avri
> -
>         if (!down_read_trylock(&hba->clk_scaling_lock))
>                 return SCSI_MLQUEUE_HOST_BUSY;