From: Bjorn Helgaas <helgaas@kernel•org>
To: Andy Shevchenko <andriy.shevchenko@linux•intel.com>
Cc: Sam Bobroff <sbobroff@linux•ibm.com>,
linuxppc-dev@lists•ozlabs.org,
Oliver O'Halloran <oohall@gmail•com>,
linux-pci@vger•kernel.org
Subject: Re: [PATCH v1 1/2] PCI/AER: Use for_each_set_bit()
Date: Fri, 27 Sep 2019 07:39:13 -0500 [thread overview]
Message-ID: <20190927123913.GA32321@google.com> (raw)
In-Reply-To: <20190827151823.75312-1-andriy.shevchenko@linux.intel.com>
On Tue, Aug 27, 2019 at 06:18:22PM +0300, Andy Shevchenko wrote:
> This simplifies and standardizes slot manipulation code
> by using for_each_set_bit() library function.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux•intel.com>
> ---
> drivers/pci/pcie/aer.c | 19 ++++++++-----------
> 1 file changed, 8 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index b45bc47d04fe..f883f81d759a 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -15,6 +15,7 @@
> #define pr_fmt(fmt) "AER: " fmt
> #define dev_fmt pr_fmt
>
> +#include <linux/bitops.h>
> #include <linux/cper.h>
> #include <linux/pci.h>
> #include <linux/pci-acpi.h>
> @@ -657,7 +658,8 @@ const struct attribute_group aer_stats_attr_group = {
> static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
> struct aer_err_info *info)
> {
> - int status, i, max = -1;
> + unsigned long status = info->status & ~info->mask;
> + int i, max = -1;
> u64 *counter = NULL;
> struct aer_stats *aer_stats = pdev->aer_stats;
>
> @@ -682,10 +684,8 @@ static void pci_dev_aer_stats_incr(struct pci_dev *pdev,
> break;
> }
>
> - status = (info->status & ~info->mask);
> - for (i = 0; i < max; i++)
> - if (status & (1 << i))
> - counter[i]++;
> + for_each_set_bit(i, &status, max)
I applied this, but I confess to being a little ambivalent. It's
arguably a little easier to read, but it's not nearly as efficient
(not a great concern here) and more importantly much harder to verify
that it's correct because you have to chase through
for_each_set_bit(), find_first_bit(), _ffs(), etc, etc. No doubt it's
great for bitmaps of arbitrary size, but for a simple 32-bit register
I'm a little hesitant. But I applied it anyway.
> + counter[i]++;
> }
>
> static void pci_rootport_aer_stats_incr(struct pci_dev *pdev,
> @@ -717,14 +717,11 @@ static void __print_tlp_header(struct pci_dev *dev,
> static void __aer_print_error(struct pci_dev *dev,
> struct aer_err_info *info)
> {
> - int i, status;
> + unsigned long status = info->status & ~info->mask;
> const char *errmsg = NULL;
> - status = (info->status & ~info->mask);
> -
> - for (i = 0; i < 32; i++) {
> - if (!(status & (1 << i)))
> - continue;
> + int i;
>
> + for_each_set_bit(i, &status, 32) {
> if (info->severity == AER_CORRECTABLE)
> errmsg = i < ARRAY_SIZE(aer_correctable_error_string) ?
> aer_correctable_error_string[i] : NULL;
> --
> 2.23.0.rc1
>
next prev parent reply other threads:[~2019-09-27 12:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 15:18 [PATCH v1 1/2] PCI/AER: Use for_each_set_bit() Andy Shevchenko
2019-08-27 15:18 ` [PATCH v1 2/2] PCI/AER: Update parameter descriptions to satisfy kernel-doc validator Andy Shevchenko
2019-08-27 17:06 ` Kuppuswamy Sathyanarayanan
2019-08-28 10:07 ` Andy Shevchenko
2019-08-27 17:06 ` [PATCH v1 1/2] PCI/AER: Use for_each_set_bit() Kuppuswamy Sathyanarayanan
2019-09-27 10:44 ` Bjorn Helgaas
2019-09-27 12:39 ` Bjorn Helgaas [this message]
2019-09-30 12:13 ` Andy Shevchenko
2019-10-02 10:27 ` David Howells
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