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SubjectRe: [PATCH v5 1/5] PCI/AER: Define and allocate aer_stats structure for AER capable devices
On Wed, Jun 20, 2018 at 04:41:43PM -0700, Rajat Jain wrote:
> Define a structure to hold the AER statistics. There are 2 groups
> of statistics: dev_* counters that are to be collected for all AER
> capable devices and rootport_* counters that are collected for all
> (AER capable) rootports only. Allocate and free this structure when
> device is added or released (thus counters survive the lifetime of the
> device).
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
> ---
> v5: Same as v4
> v4: Same as v3
> v3: Merge everything in aer.c
>
> drivers/pci/pcie/aer.c | 60 ++++++++++++++++++++++++++++++++++++++++++
> drivers/pci/probe.c | 1 +
> include/linux/pci.h | 3 +++
> 3 files changed, 64 insertions(+)
>
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index a2e88386af28..f9fa994b6c33 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -33,6 +33,9 @@
> #define AER_ERROR_SOURCES_MAX 100
> #define AER_MAX_MULTI_ERR_DEVICES 5 /* Not likely to have more */
>
> +#define AER_MAX_TYPEOF_CORRECTABLE_ERRS 16 /* as per PCI_ERR_COR_STATUS */
> +#define AER_MAX_TYPEOF_UNCORRECTABLE_ERRS 26 /* as per PCI_ERR_UNCOR_STATUS*/
> +
> struct aer_err_info {
> struct pci_dev *dev[AER_MAX_MULTI_ERR_DEVICES];
> int error_dev_num;
> @@ -76,6 +79,40 @@ struct aer_rpc {
> */
> };
>
> +/* AER stats for the device */
> +struct aer_stats {
> +
> + /*
> + * Fields for all AER capable devices. They indicate the errors
> + * "as seen by this device". Note that this may mean that if an
> + * end point is causing problems, the AER counters may increment
> + * at its link partner (e.g. root port) because the errors will be
> + * "seen" by the link partner and not the the problematic end point
> + * itself (which may report all counters as 0 as it never saw any
> + * problems).
> + */
> + /* Individual counters for different type of correctable errors */
> + u64 dev_cor_errs[AER_MAX_TYPEOF_CORRECTABLE_ERRS];
> + /* Individual counters for different type of uncorrectable errors */
> + u64 dev_uncor_errs[AER_MAX_TYPEOF_UNCORRECTABLE_ERRS];
> + /* Total number of correctable errors seen by this device */
> + u64 dev_total_cor_errs;
> + /* Total number of fatal uncorrectable errors seen by this device */
> + u64 dev_total_fatal_errs;
> + /* Total number of fatal uncorrectable errors seen by this device */
> + u64 dev_total_nonfatal_errs;
> +
> + /*
> + * Fields for Root ports only, these indicate the total number of
> + * ERR_COR, ERR_FATAL, and ERR_NONFATAL messages received by the
> + * rootport, INCLUDING the ones that are generated internally (by
> + * the rootport itself)

Strictly speaking, I think these are applicable for both root ports
and root complex event collectors, right?

> + */
> + u64 rootport_total_cor_errs;
> + u64 rootport_total_fatal_errs;
> + u64 rootport_total_nonfatal_errs;
> +};
> +
> #define AER_LOG_TLP_MASKS (PCI_ERR_UNC_POISON_TLP| \
> PCI_ERR_UNC_ECRC| \
> PCI_ERR_UNC_UNSUP| \
> @@ -402,12 +439,35 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
> return 0;
> }
>
> +static int pci_aer_stats_init(struct pci_dev *pdev)
> +{
> + pdev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);
> + if (!pdev->aer_stats) {
> + dev_err(&pdev->dev, "No memory for aer_stats\n");

pci_err(), if we need the message at all.

Based on c7abb2352c29 ("PCI: Remove unnecessary messages for memory
allocation failures"), I'd be inclined to drop the message completely.

> + return -ENOMEM;
> + }
> + return 0;
> +}
> +
> +static void pci_aer_stats_exit(struct pci_dev *pdev)
> +{
> + kfree(pdev->aer_stats);
> + pdev->aer_stats = NULL;
> +}
> +
> int pci_aer_init(struct pci_dev *dev)
> {
> dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
> + if (!dev->aer_cap || pci_aer_stats_init(dev))
> + return -EIO;

This skips pci_cleanup_aer_error_status_regs() if the kzalloc() fails.
I think we should still do pci_cleanup_aer_error_status_regs(), even
if the alloc fails.

Nobody checks the return value of pci_aer_init(), so I think you can
simplify this by making these functions void.

Maybe even squash them together, i.e., do the kzalloc() directly in
pci_aer_init() and the kfree() directly in pci_aer_exit()?

> return pci_cleanup_aer_error_status_regs(dev);
> }
>
> +void pci_aer_exit(struct pci_dev *dev)
> +{
> + pci_aer_stats_exit(dev);
> +}
> +
> #define AER_AGENT_RECEIVER 0
> #define AER_AGENT_REQUESTER 1
> #define AER_AGENT_COMPLETER 2
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index ac876e32de4b..48edd0c9e4bc 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2064,6 +2064,7 @@ static void pci_configure_device(struct pci_dev *dev)
>
> static void pci_release_capabilities(struct pci_dev *dev)
> {
> + pci_aer_exit(dev);
> pci_vpd_release(dev);
> pci_iov_release(dev);
> pci_free_cap_save_buffers(dev);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 340029b2fb38..8d59c6c19a19 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -299,6 +299,7 @@ struct pci_dev {
> u8 hdr_type; /* PCI header type (`multi' flag masked out) */
> #ifdef CONFIG_PCIEAER
> u16 aer_cap; /* AER capability offset */
> + struct aer_stats *aer_stats; /* AER stats for this device */
> #endif
> u8 pcie_cap; /* PCIe capability offset */
> u8 msi_cap; /* MSI capability offset */
> @@ -1471,10 +1472,12 @@ static inline bool pcie_aspm_support_enabled(void) { return false; }
> void pci_no_aer(void);
> bool pci_aer_available(void);
> int pci_aer_init(struct pci_dev *dev);
> +void pci_aer_exit(struct pci_dev *dev);

With the exception of pci_aer_available(), these are only used inside
drivers/pci. This might be a good opportunity to move those private
things to drivers/pci/pci.h (in a separate patch, of course).

> #else
> static inline void pci_no_aer(void) { }
> static inline bool pci_aer_available(void) { return false; }
> static inline int pci_aer_init(struct pci_dev *d) { return -ENODEV; }
> +static inline void pci_aer_exit(struct pci_dev *d) { }
> #endif
>
> #ifdef CONFIG_PCIE_ECRC
> --
> 2.18.0.rc1.244.gcf134e6275-goog
>

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