LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Amey Narkhede <ameynarkhede03@gmail.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	alex.williamson@redhat.com,
	Raphael Norwitz <raphael.norwitz@nutanix.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	kw@linux.com, Shanker Donthineni <sdonthineni@nvidia.com>,
	Sinan Kaya <okaya@kernel.org>, Len Brown <lenb@kernel.org>,
	"Rafael J . Wysocki" <rjw@rjwysocki.net>
Subject: Re: [PATCH v13 5/9] PCI: Allow userspace to query and set device reset mechanism
Date: Tue, 3 Aug 2021 12:04:24 +0530	[thread overview]
Message-ID: <20210803063424.aybmwdxxj6bt2iax@archlinux> (raw)
In-Reply-To: <20210802225559.GA1472320@bjorn-Precision-5520>

On 21/08/02 05:55PM, Bjorn Helgaas wrote:
> On Sun, Aug 01, 2021 at 07:55:14PM +0530, Amey Narkhede wrote:
> > Add reset_method sysfs attribute to enable user to query and set user
> > preferred device reset methods and their ordering.
> >
> > Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
> > ---
> > +
[...]
> > +static ssize_t reset_method_store(struct device *dev,
> > +				  struct device_attribute *attr,
> > +				  const char *buf, size_t count)
> > +{
> > +	struct pci_dev *pdev = to_pci_dev(dev);
> > +	int i = 0;
> > +	char *name, *options = NULL;
> > +
> > +	if (count >= (PAGE_SIZE - 1))
> > +		return -EINVAL;
> > +
> > +	if (sysfs_streq(buf, "")) {
> > +		pdev->reset_methods[0] = 0;
> > +		pci_warn(pdev, "All device reset methods disabled by user");
> > +		return count;
> > +	}
>
> I think it's possible for the user to disable all reset methods by
> supplying only junk.  Maybe this check could be moved to the end of
> the function to catch both the "empty input" and the "input contains
> only junk" cases?
>
Supplying only junk doesn't disable the reset. It returns -EINVAL as it
will go in following while loop. The check m == PCI_NUM_RESET_METHODS
returns -EINVAL

> > +	if (sysfs_streq(buf, "default")) {
> > +		pci_init_reset_methods(pdev);
> > +		return count;
> > +	}
> > +
> > +	options = kstrndup(buf, count, GFP_KERNEL);
> > +	if (!options)
> > +		return -ENOMEM;
> > +
>
>   i = 0;
>
> here so it's nearer the loop it controls.
>
> > +	while ((name = strsep(&options, " ")) != NULL) {
> > +		int m;
> > +
> > +		if (sysfs_streq(name, ""))
> > +			continue;
> > +
> > +		name = strim(name);
> > +
> > +		for (m = 1; m < PCI_NUM_RESET_METHODS && i < PCI_NUM_RESET_METHODS; m++) {
> > +			if (sysfs_streq(name, pci_reset_fn_methods[m].name) &&
> > +			    !pci_reset_fn_methods[m].reset_fn(pdev, 1)) {
> > +				pdev->reset_methods[i++] = m;
> > +				break;
> > +			}
> > +		}
> > +
> > +		if (m == PCI_NUM_RESET_METHODS) {
> > +			kfree(options);
> > +			return -EINVAL;
>
> In this case, I think we have actually updated pdev->reset_methods[],
> but we still return -EINVAL, right?  If we decide to silently ignore
> unrecognized methods, we probably should return success here.
>
Is it okay to do that? I hope it won't cause any trouble for user
scripts

Thanks,
Amey

[...]

  reply	other threads:[~2021-08-03  6:34 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-01 14:25 [PATCH v13 0/9] PCI: Expose and manage PCI device reset Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 1/9] PCI: Cache PCIe FLR capability Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 2/9] PCI: Add pcie_reset_flr to follow calling convention of other reset methods Amey Narkhede
2021-08-01 17:04   ` kernel test robot
2021-08-01 17:05   ` [RFC PATCH] PCI: pcie_has_flr() can be static kernel test robot
2021-08-01 18:17   ` [PATCH v13 2/9] PCI: Add pcie_reset_flr to follow calling convention of other reset methods kernel test robot
2021-08-02 22:44   ` Bjorn Helgaas
2021-08-03  4:49     ` Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 3/9] PCI: Add new array for keeping track of ordering of " Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 4/9] PCI: Remove reset_fn field from pci_dev Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 5/9] PCI: Allow userspace to query and set device reset mechanism Amey Narkhede
2021-08-02 22:55   ` Bjorn Helgaas
2021-08-03  6:34     ` Amey Narkhede [this message]
2021-08-03 13:45   ` Shanker R Donthineni
2021-08-01 14:25 ` [PATCH v13 6/9] PCI: Define a function to set ACPI_COMPANION in pci_dev Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 7/9] PCI: Setup ACPI fwnode early and at the same time with OF Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 8/9] PCI: Add support for ACPI _RST reset method Amey Narkhede
2021-08-01 14:25 ` [PATCH v13 9/9] PCI: Change the type of probe argument in reset functions Amey Narkhede
2021-08-02 22:59   ` Bjorn Helgaas

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210803063424.aybmwdxxj6bt2iax@archlinux \
    --to=ameynarkhede03@gmail.com \
    --cc=alex.williamson@redhat.com \
    --cc=bhelgaas@google.com \
    --cc=helgaas@kernel.org \
    --cc=kw@linux.com \
    --cc=lenb@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pci@vger.kernel.org \
    --cc=okaya@kernel.org \
    --cc=raphael.norwitz@nutanix.com \
    --cc=rjw@rjwysocki.net \
    --cc=sdonthineni@nvidia.com \
    --subject='Re: [PATCH v13 5/9] PCI: Allow userspace to query and set device reset mechanism' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox