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From: Frederic Barrat <fbarrat@linux.ibm.com>
To: "Alastair D'Silva" <alastair@au1.ibm.com>, alastair@d-silva.org
Cc: "Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Paul Mackerras" <paulus@samba.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Andrew Donnellan" <ajd@linux.ibm.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Mauro Carvalho Chehab" <mchehab+samsung@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"Rob Herring" <robh@kernel.org>,
	"Anton Blanchard" <anton@ozlabs.org>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Mahesh Salgaonkar" <mahesh@linux.vnet.ibm.com>,
	"Madhavan Srinivasan" <maddy@linux.vnet.ibm.com>,
	"Cédric Le Goater" <clg@kaod.org>,
	"Anju T Sudhakar" <anju@linux.vnet.ibm.com>,
	"Hari Bathini" <hbathini@linux.ibm.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Greg Kurz" <groug@kaod.org>,
	"Nicholas Piggin" <npiggin@gmail.com>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Alexey Kardashevskiy" <aik@ozlabs.ru>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-nvdimm@lists.01.org
Subject: Re: [PATCH v2 06/27] ocxl: Tally up the LPC memory on a link & allow it to be mapped
Date: Thu, 9 Jan 2020 15:48:08 +0100
Message-ID: <a2f93729-038e-9fcb-2cf0-53739ae19147@linux.ibm.com> (raw)
In-Reply-To: <20191203034655.51561-7-alastair@au1.ibm.com>



Le 03/12/2019 à 04:46, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> Tally up the LPC memory on an OpenCAPI link & allow it to be mapped
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>   drivers/misc/ocxl/core.c          | 10 ++++++
>   drivers/misc/ocxl/link.c          | 60 +++++++++++++++++++++++++++++++
>   drivers/misc/ocxl/ocxl_internal.h | 33 +++++++++++++++++
>   3 files changed, 103 insertions(+)
> 
> diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
> index b7a09b21ab36..2531c6cf19a0 100644
> --- a/drivers/misc/ocxl/core.c
> +++ b/drivers/misc/ocxl/core.c
> @@ -230,8 +230,18 @@ static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct pci_dev *dev)
>   	if (rc)
>   		goto err_free_pasid;
>   
> +	if (afu->config.lpc_mem_size || afu->config.special_purpose_mem_size) {
> +		rc = ocxl_link_add_lpc_mem(afu->fn->link, afu->config.lpc_mem_offset,
> +					   afu->config.lpc_mem_size +
> +					   afu->config.special_purpose_mem_size);
> +		if (rc)
> +			goto err_free_mmio;
> +	}
> +
>   	return 0;
>   
> +err_free_mmio:
> +	unmap_mmio_areas(afu);
>   err_free_pasid:
>   	reclaim_afu_pasid(afu);
>   err_free_actag:
> diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
> index 58d111afd9f6..d8503f0dc6ec 100644
> --- a/drivers/misc/ocxl/link.c
> +++ b/drivers/misc/ocxl/link.c
> @@ -84,6 +84,11 @@ struct ocxl_link {
>   	int dev;
>   	atomic_t irq_available;
>   	struct spa *spa;
> +	struct mutex lpc_mem_lock;
> +	u64 lpc_mem_sz; /* Total amount of LPC memory presented on the link */
> +	u64 lpc_mem;
> +	int lpc_consumers;
> +
>   	void *platform_data;
>   };
>   static struct list_head links_list = LIST_HEAD_INIT(links_list);
> @@ -396,6 +401,8 @@ static int alloc_link(struct pci_dev *dev, int PE_mask, struct ocxl_link **out_l
>   	if (rc)
>   		goto err_spa;
>   
> +	mutex_init(&link->lpc_mem_lock);
> +
>   	/* platform specific hook */
>   	rc = pnv_ocxl_spa_setup(dev, link->spa->spa_mem, PE_mask,
>   				&link->platform_data);
> @@ -711,3 +718,56 @@ void ocxl_link_free_irq(void *link_handle, int hw_irq)
>   	atomic_inc(&link->irq_available);
>   }
>   EXPORT_SYMBOL_GPL(ocxl_link_free_irq);
> +
> +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size)
> +{
> +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> +
> +	// Check for overflow
> +	if (offset > (offset + size))
> +		return -EINVAL;
> +
> +	mutex_lock(&link->lpc_mem_lock);
> +	link->lpc_mem_sz = max(link->lpc_mem_sz, offset + size);
> +
> +	mutex_unlock(&link->lpc_mem_lock);
> +
> +	return 0;
> +}
> +
> +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev)
> +{
> +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> +	u64 lpc_mem;
> +
> +	mutex_lock(&link->lpc_mem_lock);
> +	if (link->lpc_mem) {
> +		lpc_mem = link->lpc_mem;
> +
> +		link->lpc_consumers++;
> +		mutex_unlock(&link->lpc_mem_lock);
> +		return lpc_mem;
> +	}
> +
> +	link->lpc_mem = pnv_ocxl_platform_lpc_setup(pdev, link->lpc_mem_sz);
> +	if (link->lpc_mem)
> +		link->lpc_consumers++;


So if we fail to setup the lpc access in opal, we don't increment 
link->lpc_consumers and we shouldn't call ocxl_link_lpc_release(). Is 
that always true? Risk is to trigger the warning in 
ocxl_link_lpc_release(). So maybe we should check link->lpc_mem first in 
ocxl_link_lpc_release() and exit early if no memory is mapped. It would 
probably avoid hitting the WARN on an error path for example.

    Fred


> +	lpc_mem = link->lpc_mem;
> +	mutex_unlock(&link->lpc_mem_lock);
> +
> +	return lpc_mem;
> +}
> +
> +void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev)
> +{
> +	struct ocxl_link *link = (struct ocxl_link *) link_handle;
> +
> +	mutex_lock(&link->lpc_mem_lock);
> +	WARN_ON(--link->lpc_consumers < 0);
> +	if (link->lpc_consumers == 0) {
> +		pnv_ocxl_platform_lpc_release(pdev);
> +		link->lpc_mem = 0;
> +	}
> +
> +	mutex_unlock(&link->lpc_mem_lock);
> +}
> diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
> index 97415afd79f3..20b417e00949 100644
> --- a/drivers/misc/ocxl/ocxl_internal.h
> +++ b/drivers/misc/ocxl/ocxl_internal.h
> @@ -141,4 +141,37 @@ int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset);
>   u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id);
>   void ocxl_afu_irq_free_all(struct ocxl_context *ctx);
>   
> +/**
> + * ocxl_link_add_lpc_mem() - Increment the amount of memory required by an OpenCAPI link
> + *
> + * @link_handle: The OpenCAPI link handle
> + * @offset: The offset of the memory to add
> + * @size: The amount of memory to increment by
> + *
> + * Return 0 on success, negative on overflow
> + */
> +int ocxl_link_add_lpc_mem(void *link_handle, u64 offset, u64 size);
> +
> +/**
> + * ocxl_link_lpc_map() - Map the LPC memory for an OpenCAPI device
> + *
> + * Since LPC memory belongs to a link, the whole LPC memory available
> + * on the link bust be mapped in order to make it accessible to a device.
> + *
> + * @link_handle: The OpenCAPI link handle
> + * @pdev: A device that is on the link
> + */
> +u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev);
> +
> +/**
> + * ocxl_link_lpc_release() - Release the LPC memory device for an OpenCAPI device
> + *
> + * Offlines LPC memory on an OpenCAPI link for a device. If this is the
> + * last device on the link to release the memory, unmap it from the link.
> + *
> + * @link_handle: The OpenCAPI link handle
> + * @pdev: A device that is on the link
> + */
> +void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev);
> +
>   #endif /* _OCXL_INTERNAL_H_ */
> 
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  reply index

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-03  3:46 [PATCH v2 00/27] Add support for OpenCAPI SCM devices Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 01/27] memory_hotplug: Add a bounds check to __add_pages Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 02/27] nvdimm: remove prototypes for nonexistent functions Alastair D'Silva
2019-12-03  4:47   ` Andrew Donnellan
2019-12-04  0:10   ` Dan Williams
2020-01-23 21:49     ` Dan Williams
2019-12-03  3:46 ` [PATCH v2 03/27] powerpc: Add OPAL calls for LPC memory alloc/release Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 04/27] mm/memory_hotplug: Allow check_hotplug_memory_addressable to be called from drivers Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 05/27] powerpc: Map & release OpenCAPI LPC memory Alastair D'Silva
2020-01-09 14:41   ` Frederic Barrat
2020-01-21  6:46   ` Andrew Donnellan
2020-01-21  7:11     ` Greg Kurz
2020-02-14 11:09   ` Frederic Barrat
2020-02-18 23:44     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 06/27] ocxl: Tally up the LPC memory on a link & allow it to be mapped Alastair D'Silva
2020-01-09 14:48   ` Frederic Barrat [this message]
2020-02-03 12:37   ` Jonathan Cameron
2020-02-19  0:01     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 07/27] ocxl: Add functions to map/unmap LPC memory Alastair D'Silva
2020-01-09 14:49   ` Frederic Barrat
2020-02-03 12:49   ` Jonathan Cameron
2020-02-19  2:39     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 08/27] ocxl: Save the device serial number in ocxl_fn Alastair D'Silva
2020-02-03 12:53   ` Jonathan Cameron
2020-02-19  4:03     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 09/27] ocxl: Free detached contexts in ocxl_context_detach_all() Alastair D'Silva
2020-01-09 14:54   ` Frederic Barrat
2019-12-03  3:46 ` [PATCH v2 10/27] nvdimm: Add driver for OpenCAPI Storage Class Memory Alastair D'Silva
2019-12-03  5:05   ` Alastair D'Silva
2020-02-03 13:20   ` Jonathan Cameron
2020-02-19  4:40     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 11/27] nvdimm/ocxl: Add register addresses & status values to header Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 12/27] nvdimm/ocxl: Read the capability registers & wait for device ready Alastair D'Silva
2020-02-03 13:23   ` Jonathan Cameron
2020-02-19  4:46     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 13/27] nvdimm/ocxl: Add support for Admin commands Alastair D'Silva
2020-02-03 14:18   ` Jonathan Cameron
2020-02-19  5:00     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 14/27] nvdimm/ocxl: Add support for near storage commands Alastair D'Silva
2020-02-03 14:22   ` Jonathan Cameron
2020-02-19  4:54     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 15/27] nvdimm/ocxl: Register a character device for userspace to interact with Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 16/27] nvdimm/ocxl: Implement the Read Error Log command Alastair D'Silva
2019-12-05  3:42   ` Alastair D'Silva
2019-12-05 19:34   ` kbuild test robot
2019-12-03  3:46 ` [PATCH v2 17/27] nvdimm/ocxl: Add controller dump IOCTLs Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 18/27] nvdimm/ocxl: Add an IOCTL to report controller statistics Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 19/27] nvdimm/ocxl: Forward events to userspace Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 20/27] nvdimm/ocxl: Add an IOCTL to request controller health & perf data Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 21/27] nvdimm/ocxl: Support firmware update via sysfs Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 22/27] nvdimm/ocxl: Implement the heartbeat command Alastair D'Silva
2020-02-03 15:11   ` Jonathan Cameron
2020-02-19  5:02     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 23/27] nvdimm/ocxl: Add debug IOCTLs Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 24/27] nvdimm/ocxl: Implement Overwrite Alastair D'Silva
2020-02-03 15:10   ` Jonathan Cameron
2020-02-19  5:13     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 25/27] nvdimm/ocxl: Expose SMART data via ndctl Alastair D'Silva
2019-12-16  0:15   ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 26/27] powerpc: Enable OpenCAPI Storage Class Memory driver on bare metal Alastair D'Silva
2019-12-03  4:54   ` Andrew Donnellan
2019-12-03  4:57     ` Alastair D'Silva
2019-12-03  3:46 ` [PATCH v2 27/27] MAINTAINERS: Add myself & nvdimm/ocxl to ocxl Alastair D'Silva
2019-12-03  3:50 ` [PATCH v2 00/27] Add support for OpenCAPI SCM devices Matthew Wilcox
2019-12-03  4:01   ` Alastair D'Silva
2019-12-03 12:42     ` Matthew Wilcox
2019-12-04  0:15       ` Dan Williams

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