Re: [PATCH v3] fusion: remove dead MTRR code

[Sreekanth Reddy]

Hi Luis,

Sorry for delay in response. Actually I was looking for the history of
this section of code but I couldn't find it. Anyway this is dead code
and we are fine with removing this dead code.

James,

Please consider this patch as Acked-by: "Sreekanth Reddy"
<Sreekanth.reddy@xxxxxxxxxxxxx>

Regards,
Sreekanth


On Wed, Apr 22, 2015 at 2:16 AM, Luis R. Rodriguez
<mcgrof@xxxxxxxxxxxxxxxx> wrote:
> From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx>
>
> If and when this gets enabled the driver could should split
> up IO memory space properly and that is quite a bit of work.
> Just remove the uncommented dead MTRR code then.
>
> There are a few motivations for this:
>
> a) Take advantage of PAT when available
>
> b) Help bury MTRR code away, MTRR is architecture specific and on
>    x86 its replaced by PAT
>
> c) Help with the goal of eventually using _PAGE_CACHE_UC over
>    _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit
>    de33c442e titled "x86 PAT: fix performance drop for glx,
>    use UC minus for ioremap(), ioremap_nocache() and
>    pci_mmap_page_range()")
>
> Cc: Toshi Kani <toshi.kani@xxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
> Cc: Nagalakshmi Nandigama <nagalakshmi.nandigama@xxxxxxxxxxxxx>
> Cc: Praveen Krishnamoorthy <praveen.krishnamoorthy@xxxxxxxxxxxxx>
> Cc: Sreekanth Reddy <sreekanth.reddy@xxxxxxxxxxxxx>
> Cc: Abhijit Mahajan <abhijit.mahajan@xxxxxxxxxxxxx>
> Cc: linux-scsi@xxxxxxxxxxxxxxx
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> Cc: Suresh Siddha <sbsiddha@xxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
> Cc: Dave Airlie <airlied@xxxxxxxxxx>
> Cc: Antonino Daplas <adaplas@xxxxxxxxx>
> Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> Cc: Ville SyrjÃlà <syrjala@xxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxx>
> Cc: Davidlohr Bueso <dbueso@xxxxxxx>
> Cc: Jean-Christophe Plagniol-Villard <plagnioj@xxxxxxxxxxxx>
> Cc: MPT-FusionLinux.pdl@xxxxxxxxxxxxx
> Cc: linux-scsi@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxx>
> ---
>  drivers/message/fusion/mptbase.c | 24 ------------------------
>  drivers/message/fusion/mptbase.h |  1 -
>  2 files changed, 25 deletions(-)
>
> diff --git a/drivers/message/fusion/mptbase.c b/drivers/message/fusion/mptbase.c
> index 187f836..5dcc031 100644
> --- a/drivers/message/fusion/mptbase.c
> +++ b/drivers/message/fusion/mptbase.c
> @@ -59,10 +59,6 @@
>  #include <linux/delay.h>
>  #include <linux/interrupt.h>           /* needed for in_interrupt() proto */
>  #include <linux/dma-mapping.h>
> -#include <asm/io.h>
> -#ifdef CONFIG_MTRR
> -#include <asm/mtrr.h>
> -#endif
>  #include <linux/kthread.h>
>  #include <scsi/scsi_host.h>
>
> @@ -2820,13 +2816,6 @@ mpt_adapter_dispose(MPT_ADAPTER *ioc)
>         pci_disable_device(ioc->pcidev);
>         pci_release_selected_regions(ioc->pcidev, ioc->bars);
>
> -#if defined(CONFIG_MTRR) && 0
> -       if (ioc->mtrr_reg > 0) {
> -               mtrr_del(ioc->mtrr_reg, 0, 0);
> -               dprintk(ioc, printk(MYIOC_s_INFO_FMT "MTRR region de-registered\n", ioc->name));
> -       }
> -#endif
> -
>         /*  Zap the adapter lookup ptr!  */
>         list_del(&ioc->list);
>
> @@ -4512,19 +4501,6 @@ PrimeIocFifos(MPT_ADAPTER *ioc)
>
>                 ioc->req_frames_low_dma = (u32) (alloc_dma & 0xFFFFFFFF);
>
> -#if defined(CONFIG_MTRR) && 0
> -               /*
> -                *  Enable Write Combining MTRR for IOC's memory region.
> -                *  (at least as much as we can; "size and base must be
> -                *  multiples of 4 kiB"
> -                */
> -               ioc->mtrr_reg = mtrr_add(ioc->req_frames_dma,
> -                                        sz,
> -                                        MTRR_TYPE_WRCOMB, 1);
> -               dprintk(ioc, printk(MYIOC_s_DEBUG_FMT "MTRR region registered (base:size=%08x:%x)\n",
> -                               ioc->name, ioc->req_frames_dma, sz));
> -#endif
> -
>                 for (i = 0; i < ioc->req_depth; i++) {
>                         alloc_dma += ioc->req_sz;
>                         mem += ioc->req_sz;
> diff --git a/drivers/message/fusion/mptbase.h b/drivers/message/fusion/mptbase.h
> index 8f14090..813d463 100644
> --- a/drivers/message/fusion/mptbase.h
> +++ b/drivers/message/fusion/mptbase.h
> @@ -671,7 +671,6 @@ typedef struct _MPT_ADAPTER
>         u8                      *HostPageBuffer; /* SAS - host page buffer support */
>         u32                     HostPageBuffer_sz;
>         dma_addr_t              HostPageBuffer_dma;
> -       int                      mtrr_reg;
>         struct pci_dev          *pcidev;        /* struct pci_dev pointer */
>         int                     bars;           /* bitmask of BAR's that must be configured */
>         int                     msi_enable;
> --
> 2.3.2.209.gd67f9d5.dirty
>
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