From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] device-dax: avoid an unnecessary check in alloc_dev_dax_range()
Date: Fri, 18 Dec 2020 14:09:15 +0800 [thread overview]
Message-ID: <55970773-35ff-1afb-940b-8342b09aea9a@huawei.com> (raw)
In-Reply-To: <20201120092251.2197-1-thunder.leizhen@huawei.com>
On 2020/11/20 17:22, Zhen Lei wrote:
> Swap the calling sequence of krealloc() and __request_region(), call the
> latter first. In this way, the value of dev_dax->nr_range does not need to
> be considered when __request_region() failed.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
> drivers/dax/bus.c | 29 ++++++++++++-----------------
> 1 file changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 27513d311242..1efae11d947a 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -763,23 +763,15 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
> return 0;
> }
>
> - ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
> - * (dev_dax->nr_range + 1), GFP_KERNEL);
> - if (!ranges)
> - return -ENOMEM;
> -
> alloc = __request_region(res, start, size, dev_name(dev), 0);
> - if (!alloc) {
> - /*
> - * If this was an empty set of ranges nothing else
> - * will release @ranges, so do it now.
> - */
> - if (!dev_dax->nr_range) {
> - kfree(ranges);
> - ranges = NULL;
> - }
> - dev_dax->ranges = ranges;
> + if (!alloc)
> return -ENOMEM;
> +
> + ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
> + * (dev_dax->nr_range + 1), GFP_KERNEL);
> + if (!ranges) {
> + rc = -ENOMEM;
> + goto err;
Hi, Dan Williams:
In fact, after adding the new helper dev_dax_trim_range(), we can
directly call __release_region() and return error code at here. Replace goto.
> }
>
> for (i = 0; i < dev_dax->nr_range; i++)
> @@ -808,11 +800,14 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
> dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
> &alloc->start, &alloc->end);
> dev_dax->nr_range--;
> - __release_region(res, alloc->start, resource_size(alloc));
> - return rc;
> + goto err;
> }
>
> return 0;
> +
> +err:
> + __release_region(res, alloc->start, resource_size(alloc));
> + return rc;
> }
>
> static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
>
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WARNING: multiple messages have this Message-ID (diff)
From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] device-dax: avoid an unnecessary check in alloc_dev_dax_range()
Date: Fri, 18 Dec 2020 14:09:15 +0800 [thread overview]
Message-ID: <55970773-35ff-1afb-940b-8342b09aea9a@huawei.com> (raw)
In-Reply-To: <20201120092251.2197-1-thunder.leizhen@huawei.com>
On 2020/11/20 17:22, Zhen Lei wrote:
> Swap the calling sequence of krealloc() and __request_region(), call the
> latter first. In this way, the value of dev_dax->nr_range does not need to
> be considered when __request_region() failed.
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
> drivers/dax/bus.c | 29 ++++++++++++-----------------
> 1 file changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index 27513d311242..1efae11d947a 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -763,23 +763,15 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
> return 0;
> }
>
> - ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
> - * (dev_dax->nr_range + 1), GFP_KERNEL);
> - if (!ranges)
> - return -ENOMEM;
> -
> alloc = __request_region(res, start, size, dev_name(dev), 0);
> - if (!alloc) {
> - /*
> - * If this was an empty set of ranges nothing else
> - * will release @ranges, so do it now.
> - */
> - if (!dev_dax->nr_range) {
> - kfree(ranges);
> - ranges = NULL;
> - }
> - dev_dax->ranges = ranges;
> + if (!alloc)
> return -ENOMEM;
> +
> + ranges = krealloc(dev_dax->ranges, sizeof(*ranges)
> + * (dev_dax->nr_range + 1), GFP_KERNEL);
> + if (!ranges) {
> + rc = -ENOMEM;
> + goto err;
Hi, Dan Williams:
In fact, after adding the new helper dev_dax_trim_range(), we can
directly call __release_region() and return error code at here. Replace goto.
> }
>
> for (i = 0; i < dev_dax->nr_range; i++)
> @@ -808,11 +800,14 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
> dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 1,
> &alloc->start, &alloc->end);
> dev_dax->nr_range--;
> - __release_region(res, alloc->start, resource_size(alloc));
> - return rc;
> + goto err;
> }
>
> return 0;
> +
> +err:
> + __release_region(res, alloc->start, resource_size(alloc));
> + return rc;
> }
>
> static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
>
next prev parent reply other threads:[~2020-12-18 6:09 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 9:22 [PATCH 1/1] device-dax: avoid an unnecessary check in alloc_dev_dax_range() Zhen Lei
2020-11-20 9:22 ` Zhen Lei
2020-12-18 3:10 ` Dan Williams
2020-12-18 3:10 ` Dan Williams
2020-12-18 6:02 ` Leizhen (ThunderTown)
2020-12-18 6:02 ` Leizhen (ThunderTown)
2020-12-18 6:09 ` Leizhen (ThunderTown) [this message]
2020-12-18 6:09 ` Leizhen (ThunderTown)
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