Hi
[adding Steven Rostedt]
On Thu, Jul 14, 2022 at 11:02:23PM -0700, Nilesh Javali wrote:
> From: Arun Easi <aeasi@xxxxxxxxxxx>
>
> Adding a message based tracing mechanism where
> a rotating number of messages are captured in
> a trace structure. Disable/enable/resize
> operations are allowed via debugfs interfaces.
I really wonder why you need to this kind of infrastructure to your
driver? As far I know the qla2xxx is already able to log into
ftrace. Why can't we just use this infrastructure?
Thanks,
Daniel
>
> Signed-off-by: Arun Easi <aeasi@xxxxxxxxxxx>
> Signed-off-by: Nilesh Javali <njavali@xxxxxxxxxxx>
> ---
> drivers/scsi/qla2xxx/qla_dbg.c | 12 +++
> drivers/scsi/qla2xxx/qla_dbg.h | 140 +++++++++++++++++++++++++++++++++
> drivers/scsi/qla2xxx/qla_def.h | 31 ++++++++
> drivers/scsi/qla2xxx/qla_dfs.c | 102 ++++++++++++++++++++++++
> drivers/scsi/qla2xxx/qla_os.c | 5 ++
> 5 files changed, 290 insertions(+)
>
> diff --git a/drivers/scsi/qla2xxx/qla_dbg.c b/drivers/scsi/qla2xxx/qla_dbg.c
> index 7cf1f78cbaee..c4ba8ac51d27 100644
> --- a/drivers/scsi/qla2xxx/qla_dbg.c
> +++ b/drivers/scsi/qla2xxx/qla_dbg.c
> @@ -2777,3 +2777,15 @@ ql_dbg_qp(uint32_t level, struct qla_qpair *qpair, int32_t id,
> va_end(va);
>
> }
> +
> +#ifdef QLA_TRACING
> +void qla_tracing_init(void)
> +{
> + if (is_kdump_kernel())
> + return;
> +}
> +
> +void qla_tracing_exit(void)
> +{
> +}
> +#endif /* QLA_TRACING */
> diff --git a/drivers/scsi/qla2xxx/qla_dbg.h b/drivers/scsi/qla2xxx/qla_dbg.h
> index feeb1666227f..e0d91a1f81c0 100644
> --- a/drivers/scsi/qla2xxx/qla_dbg.h
> +++ b/drivers/scsi/qla2xxx/qla_dbg.h
> @@ -5,6 +5,7 @@
> */
>
> #include "qla_def.h"
> +#include <linux/delay.h>
>
> /*
> * Firmware Dump structure definition
> @@ -321,6 +322,145 @@ struct qla2xxx_fw_dump {
>
> extern uint ql_errlev;
>
> +#ifdef QLA_TRACING
> +#include <linux/crash_dump.h>
> +
> +extern void qla_tracing_init(void);
> +extern void qla_tracing_exit(void);
> +
> +static inline int
> +ql_mask_match_ext(uint level, int *log_tunable)
> +{
> + if (*log_tunable == 1)
> + *log_tunable = QL_DBG_DEFAULT1_MASK;
> +
> + return (level & *log_tunable) == level;
> +}
> +
> +static inline int
> +__qla_trace_get(struct qla_trace *trc)
> +{
> + if (test_bit(QLA_TRACE_QUIESCE, &trc->flags))
> + return -EIO;
> + atomic_inc(&trc->ref_count);
> + return 0;
> +}
> +
> +static inline int
> +qla_trace_get(struct qla_trace *trc)
> +{
> + unsigned long flags;
> + int ret;
> +
> + spin_lock_irqsave(&trc->trc_lock, flags);
> + ret = __qla_trace_get(trc);
> + spin_unlock_irqrestore(&trc->trc_lock, flags);
> +
> + return ret;
> +}
> +
> +static inline void
> +qla_trace_put(struct qla_trace *trc)
> +{
> + wmb();
> + atomic_dec(&trc->ref_count);
> +}
> +
> +static inline char *
> +qla_get_trace_next(struct qla_trace *trc)
> +{
> + uint32_t t_ind;
> + char *buf;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&trc->trc_lock, flags);
> + if (!test_bit(QLA_TRACE_ENABLED, &trc->flags) ||
> + __qla_trace_get(trc)) {
> + spin_unlock_irqrestore(&trc->trc_lock, flags);
> + return NULL;
> + }
> + t_ind = trc->trace_ind = qla_trace_ind_norm(trc, trc->trace_ind + 1);
> + spin_unlock_irqrestore(&trc->trc_lock, flags);
> +
> + if (!t_ind)
> + set_bit(QLA_TRACE_WRAPPED, &trc->flags);
> +
> + buf = qla_trace_record(trc, t_ind);
> + /* Put an end marker '>' for the next record. */
> + qla_trace_record(trc, qla_trace_ind_norm(trc, t_ind + 1))[0] = '>';
> +
> + return buf;
> +}
> +
> +static inline int
> +qla_trace_quiesce(struct qla_trace *trc)
> +{
> + unsigned long flags;
> + u32 cnt = 0;
> + int ret = 0;
> +
> + set_bit(QLA_TRACE_QUIESCE, &trc->flags);
> +
> + spin_lock_irqsave(&trc->trc_lock, flags);
> + while (atomic_read(&trc->ref_count)) {
> + spin_unlock_irqrestore(&trc->trc_lock, flags);
> +
> + msleep(1);
> +
> + spin_lock_irqsave(&trc->trc_lock, flags);
> + cnt++;
> + if (cnt > 10 * 1000) {
> + pr_info("qla2xxx: Trace could not be quiesced now (count=%d).",
> + atomic_read(&trc->ref_count));
> + /* Leave trace enabled */
> + clear_bit(QLA_TRACE_QUIESCE, &trc->flags);
> + ret = -EIO;
> + break;
> + }
> + }
> + spin_unlock_irqrestore(&trc->trc_lock, flags);
> + return ret;
> +}
> +
> +static inline void
> +qla_trace_init(struct qla_trace *trc, char *name, u32 num_entries)
> +{
> + if (trc->recs)
> + return;
> +
> + memset(trc, 0, sizeof(*trc));
> +
> + trc->name = name;
> + spin_lock_init(&trc->trc_lock);
> + if (!num_entries)
> + return;
> + trc->num_entries = num_entries;
> + trc->recs = vzalloc(trc->num_entries *
> + sizeof(struct qla_trace_rec));
> + if (!trc->recs)
> + return;
> +
> + set_bit(QLA_TRACE_ENABLED, &trc->flags);
> +}
> +
> +static inline void
> +qla_trace_uninit(struct qla_trace *trc)
> +{
> + if (!trc->recs)
> + return;
> +
> + vfree(trc->recs);
> + trc->recs = NULL;
> + clear_bit(QLA_TRACE_ENABLED, &trc->flags);
> +}
> +
> +#else /* QLA_TRACING */
> +#define qla_trace_init(trc, name, num)
> +#define qla_trace_uninit(trc)
> +#define qla_tracing_init()
> +#define qla_tracing_exit()
> +#endif /* QLA_TRACING */
> +
> void __attribute__((format (printf, 4, 5)))
> ql_dbg(uint, scsi_qla_host_t *vha, uint, const char *fmt, ...);
> void __attribute__((format (printf, 4, 5)))
> diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
> index 22274b405d01..39322105e7be 100644
> --- a/drivers/scsi/qla2xxx/qla_def.h
> +++ b/drivers/scsi/qla2xxx/qla_def.h
> @@ -35,6 +35,37 @@
>
> #include <uapi/scsi/fc/fc_els.h>
>
> +#define QLA_TRACING /* Captures driver messages to buffer */
> +
> +#ifdef QLA_TRACING
> +#define QLA_TRACE_LINE_SIZE 256 /* Biggest so far is ~215 */
> +#define qla_trace_ind_norm(_trc, _ind) ((_ind) >= (_trc)->num_entries ? \
> + 0 : (_ind))
> +#define qla_trace_record(_trc, __ind) ((_trc)->recs[__ind].buf)
> +#define qla_trace_record_len (sizeof(struct qla_trace_rec))
> +#define qla_trace_start(_trc) qla_trace_record(_trc, 0)
> +#define qla_trace_len(_trc) ((_trc)->num_entries)
> +#define qla_trace_size(_trc) (qla_trace_record_len * \
> + (_trc)->num_entries)
> +#define qla_trace_cur_ind(_trc) ((_trc)->trace_ind)
> +struct qla_trace_rec {
> + char buf[QLA_TRACE_LINE_SIZE];
> +};
> +
> +struct qla_trace {
> +#define QLA_TRACE_ENABLED 0 /* allow trace writes or not */
> +#define QLA_TRACE_WRAPPED 1
> +#define QLA_TRACE_QUIESCE 2
> + unsigned long flags;
> + atomic_t ref_count;
> + u32 num_entries;
> + u32 trace_ind;
> + spinlock_t trc_lock;
> + char *name;
> + struct qla_trace_rec *recs;
> +};
> +#endif /* QLA_TRACING */
> +
> #define QLA_DFS_DEFINE_DENTRY(_debugfs_file_name) \
> struct dentry *dfs_##_debugfs_file_name
> #define QLA_DFS_ROOT_DEFINE_DENTRY(_debugfs_file_name) \
> diff --git a/drivers/scsi/qla2xxx/qla_dfs.c b/drivers/scsi/qla2xxx/qla_dfs.c
> index c3c8b9536ef6..98c6390ad1f1 100644
> --- a/drivers/scsi/qla2xxx/qla_dfs.c
> +++ b/drivers/scsi/qla2xxx/qla_dfs.c
> @@ -489,6 +489,108 @@ qla_dfs_naqp_show(struct seq_file *s, void *unused)
> return 0;
> }
>
> +#ifdef QLA_TRACING
> +static char *trace_help = "\
> +# Format:\n\
> +# <msec> <cpu#> <message>\n\
> +#\n\
> +# Trace control by writing:\n\
> +# 'enable' - to enable this trace\n\
> +# 'disable' - to disable this trace\n\
> +# 'resize=<nlines>' - to resize this trace to <nlines>\n\
> +#\n";
> +
> +static int
> +qla_dfs_trace_show(struct seq_file *s, void *unused)
> +{
> + struct qla_trace *trc = s->private;
> + char *buf;
> + u32 t_ind = 0, i;
> +
> + seq_puts(s, trace_help);
> +
> + if (qla_trace_get(trc))
> + return 0;
> +
> + seq_printf(s, "# Trace max lines = %d, writes = %s\n#\n",
> + trc->num_entries, test_bit(QLA_TRACE_ENABLED,
> + &trc->flags) ? "enabled" : "disabled");
> +
> + if (test_bit(QLA_TRACE_WRAPPED, &trc->flags))
> + t_ind = qla_trace_cur_ind(trc) + 1;
> +
> + for (i = 0; i < qla_trace_len(trc); i++, t_ind++) {
> + t_ind = qla_trace_ind_norm(trc, t_ind);
> + buf = qla_trace_record(trc, t_ind);
> + if (!buf[0])
> + continue;
> + seq_puts(s, buf);
> + }
> +
> + mb();
> + qla_trace_put(trc);
> + return 0;
> +}
> +
> +#define string_is(_buf, _str_val) \
> + (strncmp(_str_val, _buf, strlen(_str_val)) == 0)
> +
> +static ssize_t
> +qla_dfs_trace_write(struct file *file, const char __user *buffer,
> + size_t count, loff_t *pos)
> +{
> + struct seq_file *s = file->private_data;
> + struct qla_trace *trc = s->private;
> + char buf[32];
> + ssize_t ret = count;
> +
> + memset(buf, 0, sizeof(buf));
> + if (copy_from_user(buf, buffer, min(sizeof(buf), count)))
> + return -EFAULT;
> +
> + if (string_is(buf, "enable")) {
> + if (!trc->recs) {
> + pr_warn("qla2xxx: '%s' is empty, resize before enabling.\n",
> + trc->name);
> + return -EINVAL;
> + }
> + pr_info("qla2xxx: Enabling trace '%s'\n", trc->name);
> + set_bit(QLA_TRACE_ENABLED, &trc->flags);
> + } else if (string_is(buf, "disable")) {
> + pr_info("qla2xxx: Disabling trace '%s'\n", trc->name);
> + clear_bit(QLA_TRACE_ENABLED, &trc->flags);
> + } else if (string_is(buf, "resize")) {
> + u32 new_len;
> +
> + if (sscanf(buf, "resize=%d", &new_len) != 1)
> + return -EINVAL;
> + if (new_len == trc->num_entries) {
> + pr_info("qla2xxx: New trace size is same as old.\n");
> + return count;
> + }
> + pr_info("qla2xxx: Changing trace '%s' size to %d\n",
> + trc->name, new_len);
> + if (qla_trace_quiesce(trc)) {
> + ret = -EBUSY;
> + goto done;
> + }
> + qla_trace_uninit(trc);
> + /*
> + * Go through init once again to start creating traces
> + * based on the respective tunable.
> + */
> + qla_trace_init(trc, trc->name, new_len);
> + if (!trc->recs) {
> + pr_warn("qla2xxx: Trace allocation failed for '%s'\n",
> + trc->name);
> + ret = -ENOMEM;
> + }
> + }
> +done:
> + return ret;
> +}
> +#endif /* QLA_TRACING */
> +
> /*
> * Helper macros for setting up debugfs entries.
> * _name: The name of the debugfs entry
> diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
> index 0bd0fd1042df..0d2397069cac 100644
> --- a/drivers/scsi/qla2xxx/qla_os.c
> +++ b/drivers/scsi/qla2xxx/qla_os.c
> @@ -8191,6 +8191,8 @@ qla2x00_module_init(void)
> BUILD_BUG_ON(sizeof(sw_info_t) != 32);
> BUILD_BUG_ON(sizeof(target_id_t) != 2);
>
> + qla_tracing_init();
> +
> /* Allocate cache for SRBs. */
> srb_cachep = kmem_cache_create("qla2xxx_srbs", sizeof(srb_t), 0,
> SLAB_HWCACHE_ALIGN, NULL);
> @@ -8269,6 +8271,7 @@ qla2x00_module_init(void)
>
> destroy_cache:
> kmem_cache_destroy(srb_cachep);
> + qla_tracing_exit();
> return ret;
> }
>
> @@ -8287,6 +8290,8 @@ qla2x00_module_exit(void)
> fc_release_transport(qla2xxx_transport_template);
> qlt_exit();
> kmem_cache_destroy(srb_cachep);
> +
> + qla_tracing_exit();
> }
>
> module_init(qla2x00_module_init);
> --
> 2.19.0.rc0
>
