People testing have a need to know how many errors might be occurring
over time. Add error counters and expose them via debugfs.
A module initcall is used to create a debugfs root directory for
ufshcd-related items. In the case that modules are built-in, then
initialization is done in link order, so move ufshcd-core to the top of
the Makefile.
Signed-off-by: Adrian Hunter <[email protected]>
Reviewed-by: Avri Altman <[email protected]>
---
Changes in V3:
Fixed link order to ensure correct initcall ordering when
modules are built-in.
Amended commit message accordingly.
Changes in V2:
Add missing '#include "ufs-debugfs.h"' in ufs-debugfs.c
Reported-by: kernel test robot <[email protected]>
drivers/scsi/ufs/Makefile | 13 +++++---
drivers/scsi/ufs/ufs-debugfs.c | 56 ++++++++++++++++++++++++++++++++++
drivers/scsi/ufs/ufs-debugfs.h | 22 +++++++++++++
drivers/scsi/ufs/ufshcd.c | 19 ++++++++++++
drivers/scsi/ufs/ufshcd.h | 5 +++
5 files changed, 111 insertions(+), 4 deletions(-)
create mode 100644 drivers/scsi/ufs/ufs-debugfs.c
create mode 100644 drivers/scsi/ufs/ufs-debugfs.h
diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index 4679af1b564e..06f3a3fe4a44 100644
--- a/drivers/scsi/ufs/Makefile
+++ b/drivers/scsi/ufs/Makefile
@@ -1,5 +1,14 @@
# SPDX-License-Identifier: GPL-2.0
# UFSHCD makefile
+
+# The link order is important here. ufshcd-core must initialize
+# before vendor drivers.
+obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
+ufshcd-core-y += ufshcd.o ufs-sysfs.o
+ufshcd-core-$(CONFIG_DEBUG_FS) += ufs-debugfs.o
+ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o
+ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
+
obj-$(CONFIG_SCSI_UFS_DWC_TC_PCI) += tc-dwc-g210-pci.o ufshcd-dwc.o tc-dwc-g210.o
obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-dwc-g210.o
obj-$(CONFIG_SCSI_UFS_CDNS_PLATFORM) += cdns-pltfrm.o
@@ -7,10 +16,6 @@ obj-$(CONFIG_SCSI_UFS_QCOM) += ufs_qcom.o
ufs_qcom-y += ufs-qcom.o
ufs_qcom-$(CONFIG_SCSI_UFS_CRYPTO) += ufs-qcom-ice.o
obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o
-obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
-ufshcd-core-y += ufshcd.o ufs-sysfs.o
-ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o
-ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
obj-$(CONFIG_SCSI_UFS_HISI) += ufs-hisi.o
diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-debugfs.c
new file mode 100644
index 000000000000..dee98dc72d29
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-debugfs.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2020 Intel Corporation
+
+#include <linux/debugfs.h>
+
+#include "ufs-debugfs.h"
+#include "ufshcd.h"
+
+static struct dentry *ufs_debugfs_root;
+
+void __init ufs_debugfs_init(void)
+{
+ ufs_debugfs_root = debugfs_create_dir("ufshcd", NULL);
+}
+
+void __exit ufs_debugfs_exit(void)
+{
+ debugfs_remove_recursive(ufs_debugfs_root);
+}
+
+static int ufs_debugfs_stats_show(struct seq_file *s, void *data)
+{
+ struct ufs_hba *hba = s->private;
+ struct ufs_event_hist *e = hba->ufs_stats.event;
+
+#define PRT(fmt, typ) \
+ seq_printf(s, fmt, e[UFS_EVT_ ## typ].cnt)
+
+ PRT("PHY Adapter Layer errors (except LINERESET): %llu\n", PA_ERR);
+ PRT("Data Link Layer errors: %llu\n", DL_ERR);
+ PRT("Network Layer errors: %llu\n", NL_ERR);
+ PRT("Transport Layer errors: %llu\n", TL_ERR);
+ PRT("Generic DME errors: %llu\n", DME_ERR);
+ PRT("Auto-hibernate errors: %llu\n", AUTO_HIBERN8_ERR);
+ PRT("IS Fatal errors (CEFES, SBFES, HCFES, DFES): %llu\n", FATAL_ERR);
+ PRT("DME Link Startup errors: %llu\n", LINK_STARTUP_FAIL);
+ PRT("PM Resume errors: %llu\n", RESUME_ERR);
+ PRT("PM Suspend errors : %llu\n", SUSPEND_ERR);
+ PRT("Logical Unit Resets: %llu\n", DEV_RESET);
+ PRT("Host Resets: %llu\n", HOST_RESET);
+ PRT("SCSI command aborts: %llu\n", ABORT);
+#undef PRT
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(ufs_debugfs_stats);
+
+void ufs_debugfs_hba_init(struct ufs_hba *hba)
+{
+ hba->debugfs_root = debugfs_create_dir(dev_name(hba->dev), ufs_debugfs_root);
+ debugfs_create_file("stats", 0400, hba->debugfs_root, hba, &ufs_debugfs_stats_fops);
+}
+
+void ufs_debugfs_hba_exit(struct ufs_hba *hba)
+{
+ debugfs_remove_recursive(hba->debugfs_root);
+}
diff --git a/drivers/scsi/ufs/ufs-debugfs.h b/drivers/scsi/ufs/ufs-debugfs.h
new file mode 100644
index 000000000000..f35b39c4b4f5
--- /dev/null
+++ b/drivers/scsi/ufs/ufs-debugfs.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2020 Intel Corporation
+ */
+
+#ifndef __UFS_DEBUGFS_H__
+#define __UFS_DEBUGFS_H__
+
+struct ufs_hba;
+
+#ifdef CONFIG_DEBUG_FS
+void __init ufs_debugfs_init(void);
+void __exit ufs_debugfs_exit(void);
+void ufs_debugfs_hba_init(struct ufs_hba *hba);
+void ufs_debugfs_hba_exit(struct ufs_hba *hba);
+#else
+static inline void ufs_debugfs_init(void) {}
+static inline void ufs_debugfs_exit(void) {}
+static inline void ufs_debugfs_hba_init(struct ufs_hba *hba) {}
+static inline void ufs_debugfs_hba_exit(struct ufs_hba *hba) {}
+#endif
+
+#endif
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 82ad31781bc9..d8a3cf0cd6d5 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -20,6 +20,7 @@
#include "ufs_quirks.h"
#include "unipro.h"
#include "ufs-sysfs.h"
+#include "ufs-debugfs.h"
#include "ufs_bsg.h"
#include "ufshcd-crypto.h"
#include <asm/unaligned.h>
@@ -4540,6 +4541,7 @@ void ufshcd_update_evt_hist(struct ufs_hba *hba, u32 id, u32 val)
e = &hba->ufs_stats.event[id];
e->val[e->pos] = val;
e->tstamp[e->pos] = ktime_get();
+ e->cnt += 1;
e->pos = (e->pos + 1) % UFS_EVENT_HIST_LENGTH;
ufshcd_vops_event_notify(hba, id, &val);
@@ -8334,6 +8336,8 @@ static int ufshcd_hba_init(struct ufs_hba *hba)
if (err)
goto out_disable_vreg;
+ ufs_debugfs_hba_init(hba);
+
hba->is_powered = true;
goto out;
@@ -8350,6 +8354,7 @@ static int ufshcd_hba_init(struct ufs_hba *hba)
static void ufshcd_hba_exit(struct ufs_hba *hba)
{
if (hba->is_powered) {
+ ufs_debugfs_hba_exit(hba);
ufshcd_variant_hba_exit(hba);
ufshcd_setup_vreg(hba, false);
ufshcd_suspend_clkscaling(hba);
@@ -9436,6 +9441,20 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
}
EXPORT_SYMBOL_GPL(ufshcd_init);
+static int __init ufshcd_core_init(void)
+{
+ ufs_debugfs_init();
+ return 0;
+}
+
+static void __exit ufshcd_core_exit(void)
+{
+ ufs_debugfs_exit();
+}
+
+module_init(ufshcd_core_init);
+module_exit(ufshcd_core_exit);
+
MODULE_AUTHOR("Santosh Yaragnavi <[email protected]>");
MODULE_AUTHOR("Vinayak Holikatti <[email protected]>");
MODULE_DESCRIPTION("Generic UFS host controller driver Core");
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index aa9ea3552323..8c51ce01517e 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -445,11 +445,13 @@ struct ufs_clk_scaling {
* @pos: index to indicate cyclic buffer position
* @reg: cyclic buffer for registers value
* @tstamp: cyclic buffer for time stamp
+ * @cnt: error counter
*/
struct ufs_event_hist {
int pos;
u32 val[UFS_EVENT_HIST_LENGTH];
ktime_t tstamp[UFS_EVENT_HIST_LENGTH];
+ unsigned long long cnt;
};
/**
@@ -817,6 +819,9 @@ struct ufs_hba {
u32 crypto_cfg_register;
struct blk_keyslot_manager ksm;
#endif
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *debugfs_root;
+#endif
};
/* Returns true if clocks can be gated. Otherwise false */
--
2.17.1
On Fri, 2020-12-18 at 14:20 +0200, Adrian Hunter wrote:
> People testing have a need to know how many errors might be occurring
> over time. Add error counters and expose them via debugfs.
>
> A module initcall is used to create a debugfs root directory for
> ufshcd-related items. In the case that modules are built-in, then
> initialization is done in link order, so move ufshcd-core to the top
> of
> the Makefile.
>
> Signed-off-by: Adrian Hunter <[email protected]>
> Reviewed-by: Avri Altman <[email protected]>
> ---
>
>
> Changes in V3:
> Fixed link order to ensure correct initcall ordering when
> modules are built-in.
> Amended commit message accordingly.
>
> Changes in V2:
> Add missing '#include "ufs-debugfs.h"' in ufs-debugfs.c
> Reported-by: kernel test robot <[email protected]>
>
>
> drivers/scsi/ufs/Makefile | 13 +++++---
> drivers/scsi/ufs/ufs-debugfs.c | 56
> ++++++++++++++++++++++++++++++++++
> drivers/scsi/ufs/ufs-debugfs.h | 22 +++++++++++++
> drivers/scsi/ufs/ufshcd.c | 19 ++++++++++++
> drivers/scsi/ufs/ufshcd.h | 5 +++
> 5 files changed, 111 insertions(+), 4 deletions(-)
> create mode 100644 drivers/scsi/ufs/ufs-debugfs.c
> create mode 100644 drivers/scsi/ufs/ufs-debugfs.h
>
> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
> index 4679af1b564e..06f3a3fe4a44 100644
> --- a/drivers/scsi/ufs/Makefile
> +++ b/drivers/scsi/ufs/Makefile
> @@ -1,5 +1,14 @@
> # SPDX-License-Identifier: GPL-2.0
> # UFSHCD makefile
> +
> +# The link order is important here. ufshcd-core must initialize
> +# before vendor drivers.
> +obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
> +ufshcd-core-y += ufshcd.o ufs-sysfs.o
> +ufshcd-core-$(CONFIG_DEBUG_FS) += ufs-debugfs.o
> +ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o
> +ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
> +
> obj-$(CONFIG_SCSI_UFS_DWC_TC_PCI) += tc-dwc-g210-pci.o ufshcd-dwc.o
> tc-dwc-g210.o
> obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o
> ufshcd-dwc.o tc-dwc-g210.o
> obj-$(CONFIG_SCSI_UFS_CDNS_PLATFORM) += cdns-pltfrm.o
> @@ -7,10 +16,6 @@ obj-$(CONFIG_SCSI_UFS_QCOM) += ufs_qcom.o
> ufs_qcom-y += ufs-qcom.o
> ufs_qcom-$(CONFIG_SCSI_UFS_CRYPTO) += ufs-qcom-ice.o
> obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o
> -obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
> -ufshcd-core-y += ufshcd.o ufs-sysfs.o
> -ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o
> -ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
> obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
> obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
> obj-$(CONFIG_SCSI_UFS_HISI) += ufs-hisi.o
> diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-
> debugfs.c
> new file mode 100644
> index 000000000000..dee98dc72d29
> --- /dev/null
> +++ b/drivers/scsi/ufs/ufs-debugfs.c
> @@ -0,0 +1,56 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (C) 2020 Intel Corporation
> +
> +#include <linux/debugfs.h>
> +
> +#include "ufs-debugfs.h"
> +#include "ufshcd.h"
> +
> +static struct dentry *ufs_debugfs_root;
> +
> +void __init ufs_debugfs_init(void)
> +{
> + ufs_debugfs_root = debugfs_create_dir("ufshcd", NULL);
> +}
> +
> +void __exit ufs_debugfs_exit(void)
> +{
> + debugfs_remove_recursive(ufs_debugfs_root);
> +}
> +
> +static int ufs_debugfs_stats_show(struct seq_file *s, void *data)
> +{
> + struct ufs_hba *hba = s->private;
> + struct ufs_event_hist *e = hba->ufs_stats.event;
> +
> +#define PRT(fmt, typ) \
> + seq_printf(s, fmt, e[UFS_EVT_ ## typ].cnt)
> +
> + PRT("PHY Adapter Layer errors (except LINERESET): %llu\n",
> PA_ERR);
> + PRT("Data Link Layer errors: %llu\n", DL_ERR);
> + PRT("Network Layer errors: %llu\n", NL_ERR);
> + PRT("Transport Layer errors: %llu\n", TL_ERR);
> + PRT("Generic DME errors: %llu\n", DME_ERR);
> + PRT("Auto-hibernate errors: %llu\n", AUTO_HIBERN8_ERR);
> + PRT("IS Fatal errors (CEFES, SBFES, HCFES, DFES): %llu\n",
> FATAL_ERR);
> + PRT("DME Link Startup errors: %llu\n", LINK_STARTUP_FAIL);
> + PRT("PM Resume errors: %llu\n", RESUME_ERR);
> + PRT("PM Suspend errors : %llu\n", SUSPEND_ERR);
> + PRT("Logical Unit Resets: %llu\n", DEV_RESET);
> + PRT("Host Resets: %llu\n", HOST_RESET);
> + PRT("SCSI command aborts: %llu\n", ABORT);
> +#undef PRT
> + return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(ufs_debugfs_stats);
> +
> +void ufs_debugfs_hba_init(struct ufs_hba *hba)
> +{
I prefer adding:
if (!ufs_debugfs_root)
return;
> + hba->debugfs_root = debugfs_create_dir(dev_name(hba->dev),
> ufs_debugfs_root);
> + debugfs_create_file("stats", 0400, hba->debugfs_root, hba,
> &ufs_debugfs_stats_fops);
if (!debugfs_create_file("stats", 0400, hba->debugfs_root, hba,
&ufs_debugfs_stats_fops)) {
debugfs_remove(hba->debugfs_root);
return -ENOMEM;
}
Thanks,
Bean
On 18/12/20 5:17 pm, Bean Huo wrote:
> On Fri, 2020-12-18 at 14:20 +0200, Adrian Hunter wrote:
>> People testing have a need to know how many errors might be occurring
>> over time. Add error counters and expose them via debugfs.
>>
>> A module initcall is used to create a debugfs root directory for
>> ufshcd-related items. In the case that modules are built-in, then
>> initialization is done in link order, so move ufshcd-core to the top
>> of
>> the Makefile.
>>
>> Signed-off-by: Adrian Hunter <[email protected]>
>> Reviewed-by: Avri Altman <[email protected]>
>> ---
>>
>>
>> Changes in V3:
>> Fixed link order to ensure correct initcall ordering when
>> modules are built-in.
>> Amended commit message accordingly.
>>
>> Changes in V2:
>> Add missing '#include "ufs-debugfs.h"' in ufs-debugfs.c
>> Reported-by: kernel test robot <[email protected]>
>>
>>
>> drivers/scsi/ufs/Makefile | 13 +++++---
>> drivers/scsi/ufs/ufs-debugfs.c | 56
>> ++++++++++++++++++++++++++++++++++
>> drivers/scsi/ufs/ufs-debugfs.h | 22 +++++++++++++
>> drivers/scsi/ufs/ufshcd.c | 19 ++++++++++++
>> drivers/scsi/ufs/ufshcd.h | 5 +++
>> 5 files changed, 111 insertions(+), 4 deletions(-)
>> create mode 100644 drivers/scsi/ufs/ufs-debugfs.c
>> create mode 100644 drivers/scsi/ufs/ufs-debugfs.h
>>
>> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
>> index 4679af1b564e..06f3a3fe4a44 100644
>> --- a/drivers/scsi/ufs/Makefile
>> +++ b/drivers/scsi/ufs/Makefile
>> @@ -1,5 +1,14 @@
>> # SPDX-License-Identifier: GPL-2.0
>> # UFSHCD makefile
>> +
>> +# The link order is important here. ufshcd-core must initialize
>> +# before vendor drivers.
>> +obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>> +ufshcd-core-y += ufshcd.o ufs-sysfs.o
>> +ufshcd-core-$(CONFIG_DEBUG_FS) += ufs-debugfs.o
>> +ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o
>> +ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
>> +
>> obj-$(CONFIG_SCSI_UFS_DWC_TC_PCI) += tc-dwc-g210-pci.o ufshcd-dwc.o
>> tc-dwc-g210.o
>> obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) += tc-dwc-g210-pltfrm.o
>> ufshcd-dwc.o tc-dwc-g210.o
>> obj-$(CONFIG_SCSI_UFS_CDNS_PLATFORM) += cdns-pltfrm.o
>> @@ -7,10 +16,6 @@ obj-$(CONFIG_SCSI_UFS_QCOM) += ufs_qcom.o
>> ufs_qcom-y += ufs-qcom.o
>> ufs_qcom-$(CONFIG_SCSI_UFS_CRYPTO) += ufs-qcom-ice.o
>> obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o
>> -obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>> -ufshcd-core-y += ufshcd.o ufs-sysfs.o
>> -ufshcd-core-$(CONFIG_SCSI_UFS_BSG) += ufs_bsg.o
>> -ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
>> obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
>> obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
>> obj-$(CONFIG_SCSI_UFS_HISI) += ufs-hisi.o
>> diff --git a/drivers/scsi/ufs/ufs-debugfs.c b/drivers/scsi/ufs/ufs-
>> debugfs.c
>> new file mode 100644
>> index 000000000000..dee98dc72d29
>> --- /dev/null
>> +++ b/drivers/scsi/ufs/ufs-debugfs.c
>> @@ -0,0 +1,56 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright (C) 2020 Intel Corporation
>> +
>> +#include <linux/debugfs.h>
>> +
>> +#include "ufs-debugfs.h"
>> +#include "ufshcd.h"
>> +
>> +static struct dentry *ufs_debugfs_root;
>> +
>> +void __init ufs_debugfs_init(void)
>> +{
>> + ufs_debugfs_root = debugfs_create_dir("ufshcd", NULL);
>> +}
>> +
>> +void __exit ufs_debugfs_exit(void)
>> +{
>> + debugfs_remove_recursive(ufs_debugfs_root);
>> +}
>> +
>> +static int ufs_debugfs_stats_show(struct seq_file *s, void *data)
>> +{
>> + struct ufs_hba *hba = s->private;
>> + struct ufs_event_hist *e = hba->ufs_stats.event;
>> +
>> +#define PRT(fmt, typ) \
>> + seq_printf(s, fmt, e[UFS_EVT_ ## typ].cnt)
>> +
>> + PRT("PHY Adapter Layer errors (except LINERESET): %llu\n",
>> PA_ERR);
>> + PRT("Data Link Layer errors: %llu\n", DL_ERR);
>> + PRT("Network Layer errors: %llu\n", NL_ERR);
>> + PRT("Transport Layer errors: %llu\n", TL_ERR);
>> + PRT("Generic DME errors: %llu\n", DME_ERR);
>> + PRT("Auto-hibernate errors: %llu\n", AUTO_HIBERN8_ERR);
>> + PRT("IS Fatal errors (CEFES, SBFES, HCFES, DFES): %llu\n",
>> FATAL_ERR);
>> + PRT("DME Link Startup errors: %llu\n", LINK_STARTUP_FAIL);
>> + PRT("PM Resume errors: %llu\n", RESUME_ERR);
>> + PRT("PM Suspend errors : %llu\n", SUSPEND_ERR);
>> + PRT("Logical Unit Resets: %llu\n", DEV_RESET);
>> + PRT("Host Resets: %llu\n", HOST_RESET);
>> + PRT("SCSI command aborts: %llu\n", ABORT);
>> +#undef PRT
>> + return 0;
>> +}
>> +DEFINE_SHOW_ATTRIBUTE(ufs_debugfs_stats);
>> +
>> +void ufs_debugfs_hba_init(struct ufs_hba *hba)
>> +{
>
> I prefer adding:
> if (!ufs_debugfs_root)
> return;
I understand that you want to be careful, but it is not harmful if it is
NULL, so are you sure we should do this?
>
>> + hba->debugfs_root = debugfs_create_dir(dev_name(hba->dev),
>> ufs_debugfs_root);
It is OK to pass NULL or error codes as parent dentry to debugfs_create_...
functions.
If ufs_debugfs_root is NULL (which won't happen) then the directory will be
created in debugfs root i.e. /sys/kernel/debug, using the device name.
If ufs_debugfs_root is an error code, then debugfs_create_dir will return an
error code, and following debugfs_create_file() will return an error code.
>
>> + debugfs_create_file("stats", 0400, hba->debugfs_root, hba,
>> &ufs_debugfs_stats_fops);
>
> if (!debugfs_create_file("stats", 0400, hba->debugfs_root, hba,
> &ufs_debugfs_stats_fops)) {
> debugfs_remove(hba->debugfs_root);
> return -ENOMEM;
Being without debugfs files is not a problem, so there is no reason to
return an error. It is relatively rare in the kernel that code checks the
return value of debugfs_create_file(). We really don't want to fail probing
just because of debugfs.
However, because debugfs' only real resource is a small amount of memory, it
is extremely unlikely it will fail in that sense. Although you can force it
to fail by adding the kernel command line parameter debugfs=off
On Fri, 2020-12-18 at 20:34 +0200, Adrian Hunter wrote:
> It is OK to pass NULL or error codes as parent dentry to
> debugfs_create_...
> functions.
>
> If ufs_debugfs_root is NULL (which won't happen) then the directory
> will be
> created in debugfs root i.e. /sys/kernel/debug, using the device
> name.
>
> If ufs_debugfs_root is an error code, then debugfs_create_dir will
> return an
> error code, and following debugfs_create_file() will return an error
> code.
>
> >
> > > + debugfs_create_file("stats", 0400, hba->debugfs_root, hba,
> > > &ufs_debugfs_stats_fops);
> >
> > if (!debugfs_create_file("stats", 0400, hba->debugfs_root,
> > hba,
> > &ufs_debugfs_stats_fops)) {
> > debugfs_remove(hba->debugfs_root);
> > return -ENOMEM;
>
> Being without debugfs files is not a problem, so there is no reason
> to
> return an error. It is relatively rare in the kernel that code
> checks the
> return value of debugfs_create_file(). We really don't want to fail
> probing
> just because of debugfs.
>
> However, because debugfs' only real resource is a small amount of
> memory, it
> is extremely unlikely it will fail in that sense. Although you can
> force it
> to fail by adding the kernel command line parameter debugfs=off
Adrian
Sounds your choice is correct. thanks.
Reviewed-by: Bean Huo <[email protected]>