linux-kernel - Re: [PATCH v8 5/8] PCI: endpoint: Add support to handle multiple base for mapping outbound memory

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Message-ID: <CA+V-a8vkZwgOf8gkxWU62A3L1BTXw_y2H5MGo-7-+ad28q1tWQ@mail.gmail.com>
Date:   Mon, 20 Apr 2020 10:17:08 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Cc:     Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh+dt@...nel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Andrew Murray <amurray@...goodpenguin.co.uk>,
        Tom Joseph <tjoseph@...ence.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Marek Vasut <marek.vasut+renesas@...il.com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>,
        "linux-rockchip@...ts.infradead.org" 
        <linux-rockchip@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v8 5/8] PCI: endpoint: Add support to handle multiple base
 for mapping outbound memory

Hi Yoshihiro,

Thank you for the review.

On Mon, Apr 20, 2020 at 10:04 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@...esas.com> wrote:
>
> Hi Prabhakar-san,
>
> Thank you for the patch!
>
> > From: Lad Prabhakar, Sent: Sunday, April 19, 2020 10:27 PM
> <snip>
> > @@ -109,11 +137,22 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_init);
> >   */
> >  void pci_epc_mem_exit(struct pci_epc *epc)
> >  {
> > -     struct pci_epc_mem *mem = epc->mem;
> > +     struct pci_epc_mem *mem;
> > +     int i;
> >
> > +     if (!epc->num_windows)
> > +             return;
> > +
> > +     for (i = 0; i <= epc->num_windows; i++) {
>
> I'm sorry, I overlooked when I reviewed before.
> This condition should be "i < epc->num_windows".
>
Argh my bad, will fix it.

> > +             mem = epc->windows[i];
> > +             kfree(mem->bitmap);
> > +             kfree(mem);
> > +     }
> > +     kfree(epc->windows);
> > +
> > +     epc->windows = NULL;
> >       epc->mem = NULL;
> > -     kfree(mem->bitmap);
> > -     kfree(mem);
> > +     epc->num_windows = 0;
> >  }
> >  EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
> >
> > @@ -129,31 +168,57 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
> >  void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> >                                    phys_addr_t *phys_addr, size_t size)
> >  {
> > -     int pageno;
> >       void __iomem *virt_addr = NULL;
> > -     struct pci_epc_mem *mem = epc->mem;
> > -     unsigned int page_shift = ilog2(mem->page_size);
> > +     struct pci_epc_mem *mem;
> > +     unsigned int page_shift;
> > +     size_t align_size;
> > +     int pageno;
> >       int order;
> > +     int i;
> >
> > -     size = ALIGN(size, mem->page_size);
> > -     order = pci_epc_mem_get_order(mem, size);
> > -
> > -     mutex_lock(&mem->lock);
> > -     pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
> > -     if (pageno < 0)
> > -             goto ret;
> > +     for (i = 0; i < epc->num_windows; i++) {
> > +             mem = epc->windows[i];
> > +             mutex_lock(&mem->lock);
> > +             align_size = ALIGN(size, mem->window.page_size);
> > +             order = pci_epc_mem_get_order(mem, align_size);
> >
> > -     *phys_addr = mem->phys_base + ((phys_addr_t)pageno << page_shift);
> > -     virt_addr = ioremap(*phys_addr, size);
> > -     if (!virt_addr)
> > -             bitmap_release_region(mem->bitmap, pageno, order);
> > +             pageno = bitmap_find_free_region(mem->bitmap, mem->pages,
> > +                                              order);
> > +             if (pageno >= 0) {
> > +                     page_shift = ilog2(mem->window.page_size);
> > +                     *phys_addr = mem->window.phys_base +
> > +                             ((phys_addr_t)pageno << page_shift);
> > +                     virt_addr = ioremap(*phys_addr, align_size);
> > +                     if (!virt_addr)
> > +                             bitmap_release_region(mem->bitmap,
> > +                                                   pageno, order);
>
> I'm sorry here again. But, I think we should call mutex_unlock() and "continue;"
> here if ioremap() failed for trying remaining windows. What do you think?
>
If ioremap() has failed something has really went wrong with the
system, but there is no harm in trying other windows. So Ill add the
code as suggested above.

Cheers,
--Prabhakar

> > +                     mutex_unlock(&mem->lock);
> > +                     return virt_addr;
> > +             }
> > +             mutex_unlock(&mem->lock);
> > +     }
> >
> > -ret:
> > -     mutex_unlock(&mem->lock);
> >       return virt_addr;
> >  }
> >  EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>
> Best regards,
> Yoshihiro Shimoda
>