On Sun, Apr 18, 2021 at 11:19:29AM +0200, Heiner Kallweit wrote:
> Use helper get_unaligned_le32() to simplify the code.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
> ---
> drivers/pci/vpd.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
> index 60573f27a..2888bb300 100644
> --- a/drivers/pci/vpd.c
> +++ b/drivers/pci/vpd.c
> @@ -9,6 +9,7 @@
> #include <linux/delay.h>
> #include <linux/export.h>
> #include <linux/sched/signal.h>
> +#include <asm/unaligned.h>
> #include "pci.h"
>
> /* VPD access through PCI 2.2+ VPD capability */
> @@ -235,10 +236,9 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
> }
>
> static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
> - const void *arg)
> + const void *buf)
> {
> struct pci_vpd *vpd = dev->vpd;
> - const u8 *buf = arg;
> loff_t end = pos + count;
> int ret = 0;
>
> @@ -264,14 +264,8 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
> goto out;
>
> while (pos < end) {
> - u32 val;
> -
> - val = *buf++;
> - val |= *buf++ << 8;
> - val |= *buf++ << 16;
> - val |= *buf++ << 24;
> -
> - ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val);
> + ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA,
> + get_unaligned_le32(buf));
If I understand correctly, get_unaligned_le32() is equivalent to the
open-coded "val = *buf++; ..." In other words, this doesn't fix a bug
on any platforms, and it doesn't change the bits written to VPD.
Right?
If so, this makes sense. I'd like it better if we could also make
pci_vpd_read() look more symmetric, since it has similar byte
order-related code. The read side is a little more complicated since
the size need not be 4-byte aligned. But maybe there's a way? Seems
like there should be other examples of this sort of thing, but my
quick look didn't find one.
> if (ret < 0)
> break;
> ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
> @@ -286,6 +280,7 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
> break;
>
> pos += sizeof(u32);
> + buf += sizeof(u32);
> }
> out:
> mutex_unlock(&vpd->lock);
> --
> 2.31.1
>
