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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Thu, 27 Jan 2022 14:47:04 -0800
Message-ID: <CAKwvOdnWHVV+3s8SO=Q8FfZ7hVekRVDL5q+7CwAk_z44xaex8w@mail.gmail.com>
Subject: Re: [PATCH] scsi: megaraid: cleanup formatting of megaraid
To:     Finn Thain <fthain@linux-m68k.org>, Miguel Ojeda <ojeda@kernel.org>
Cc:     Tom Rix <trix@redhat.com>, kashyap.desai@broadcom.com,
        sumit.saxena@broadcom.com, shivasharan.srikanteshwara@broadcom.com,
        jejb@linux.ibm.com, martin.petersen@oracle.com, nathan@kernel.org,
        megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        Joe Perches <joe@perches.com>
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+ Miguel (the clang-format maintainer), Joe (checkpatch maintainer)
These criticisms are worth reviewing.

On Thu, Jan 27, 2022 at 2:38 PM Finn Thain <fthain@linux-m68k.org> wrote:
>
>
> On Thu, 27 Jan 2022, trix@redhat.com wrote:
>
> > From: Tom Rix <trix@redhat.com>
> >
> > checkpatch reports several hundred formatting errors. Run these files
> > through clang-format and knock off some of them.
> >
>
> That method seems like a good recipe for endless churn unless checkpatch
> and clang-format really agree about these style rules.
>
> Why use checkpatch to assess code style, if we could simply diff the
> existing source with the output from clang-format... but it seems that
> clang-format harms readability, makes indentation errors and uses
> inconsistent style rules. Some examples:
>
> >  static unsigned short int max_sectors_per_io = MAX_SECTORS_PER_IO;
> >  module_param(max_sectors_per_io, ushort, 0);
> > -MODULE_PARM_DESC(max_sectors_per_io, "Maximum number of sectors per I/O request (default=MAX_SECTORS_PER_IO=128)");
> > -
> > +MODULE_PARM_DESC(
> > +     max_sectors_per_io,
> > +     "Maximum number of sectors per I/O request (default=MAX_SECTORS_PER_IO=128)");
> >
> >  static unsigned short int max_mbox_busy_wait = MBOX_BUSY_WAIT;
> >  module_param(max_mbox_busy_wait, ushort, 0);
> > -MODULE_PARM_DESC(max_mbox_busy_wait, "Maximum wait for mailbox in microseconds if busy (default=MBOX_BUSY_WAIT=10)");
> > +MODULE_PARM_DESC(
> > +     max_mbox_busy_wait,
> > +     "Maximum wait for mailbox in microseconds if busy (default=MBOX_BUSY_WAIT=10)");
> >
>
> This code is longer for no real improvement.
>
> >
> >  /*
> >   * The File Operations structure for the serial/ioctl interface of the driver
> >   */
> >  static const struct file_operations megadev_fops = {
> > -     .owner          = THIS_MODULE,
> > -     .unlocked_ioctl = megadev_unlocked_ioctl,
> > -     .open           = megadev_open,
> > -     .llseek         = noop_llseek,
> > +     .owner = THIS_MODULE,
> > +     .unlocked_ioctl = megadev_unlocked_ioctl,
> > +     .open = megadev_open,
> > +     .llseek = noop_llseek,
> >  };
> >
> >  /*
>
> Readability loss.
>
> > -             prod_info_dma_handle = dma_map_single(&adapter->dev->dev,
> > -                                                   (void *)&adapter->product_info,
> > -                                                   sizeof(mega_product_info),
> > -                                                   DMA_FROM_DEVICE);
> > +             prod_info_dma_handle = dma_map_single(
> > +                     &adapter->dev->dev, (void *)&adapter->product_info,
> > +                     sizeof(mega_product_info), DMA_FROM_DEVICE);
> >
>
> Note the orphaned first parameter and odd indentation.
>
> >
> >  static DEF_SCSI_QCMD(megaraid_queue)
> >
> > -/**
> > +     /**
> >   * mega_allocate_scb()
> >   * @adapter: pointer to our soft state
> >   * @cmd: scsi command from the mid-layer
>
> Indentation error.
>
> > @@ -418,15 +409,14 @@ static DEF_SCSI_QCMD(megaraid_queue)
> >   * Allocate a SCB structure. This is the central structure for controller
> >   * commands.
> >   */
> > -static inline scb_t *
> > -mega_allocate_scb(adapter_t *adapter, struct scsi_cmnd *cmd)
> > +     static inline scb_t *mega_allocate_scb(adapter_t *adapter,
> > +                                            struct scsi_cmnd *cmd)
> >  {
> >       struct list_head *head = &adapter->free_list;
>
> Same.
>
> > @@ -586,26 +568,25 @@ mega_build_cmd(adapter_t *adapter, struct scsi_cmnd *cmd, int *busy)
> >
> >               ldrv_num = mega_get_ldrv_num(adapter, cmd, channel);
> >
> > -
> >               max_ldrv_num = (adapter->flag & BOARD_40LD) ?
> > -                     MAX_LOGICAL_DRIVES_40LD : MAX_LOGICAL_DRIVES_8LD;
> > +                                    MAX_LOGICAL_DRIVES_40LD :
> > +                                          MAX_LOGICAL_DRIVES_8LD;
> >
>
> Churn, if not readability loss. Note the indentation change here is
> inconsistent with the indentation change noted above.
>
> >                        * 6-byte READ(0x08) or WRITE(0x0A) cdb
> >                        */
> > -                     if( cmd->cmd_len == 6 ) {
> > -                             mbox->m_out.numsectors = (u32) cmd->cmnd[4];
> > -                             mbox->m_out.lba =
> > -                                     ((u32)cmd->cmnd[1] << 16) |
> > -                                     ((u32)cmd->cmnd[2] << 8) |
> > -                                     (u32)cmd->cmnd[3];
> > +                     if (cmd->cmd_len == 6) {
> > +                             mbox->m_out.numsectors = (u32)cmd->cmnd[4];
> > +                             mbox->m_out.lba = ((u32)cmd->cmnd[1] << 16) |
> > +                                               ((u32)cmd->cmnd[2] << 8) |
> > +                                               (u32)cmd->cmnd[3];
> >
> >                               mbox->m_out.lba &= 0x1FFFFF;
> >
>
> Here, the orphaned term is moved up, next to the =. And yet,
>
> >
> >                       /* Calculate Scatter-Gather info */
> > -                     mbox->m_out.numsgelements = mega_build_sglist(adapter, scb,
> > -                                     (u32 *)&mbox->m_out.xferaddr, &seg);
> > +                     mbox->m_out.numsgelements =
> > +                             mega_build_sglist(adapter, scb,
> > +                                               (u32 *)&mbox->m_out.xferaddr,
> > +                                               &seg);
> >
> >                       return scb;
> >
>
> ... here the first term is moved down and orphaned, which is another
> inconsistency.


-- 
Thanks,
~Nick Desaulniers