[RFC PATCH v4 7/9] printk-rb: increase size of seq and size variables

John Ogness
2019-08-07T22:27:42Z

The printk implementation will rely on sequence numbers never
wrapping. For 32-bit systems, an unsigned long for sequence
numbers is not acceptable. Change the sequence number to u64.

Size variables are currently unsigned int, which may not be
acceptable for 64-bit systems. Change size variables to
unsigned long. (32-bit sizes on 32-bit systems should be fine.)

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
kernel/printk/dataring.c | 8 ++++----
kernel/printk/dataring.h | 4 ++--
kernel/printk/numlist.c | 6 +++---
kernel/printk/numlist.h | 6 +++---
kernel/printk/ringbuffer.c | 6 +++---
kernel/printk/ringbuffer.h | 10 +++++-----
kernel/printk/test_prb.c | 14 +++++++-------
7 files changed, 27 insertions(+), 27 deletions(-)

diff --git a/kernel/printk/dataring.c b/kernel/printk/dataring.c
index 345c46dba5bb..712842f2dc04 100644
--- a/kernel/printk/dataring.c
+++ b/kernel/printk/dataring.c
@@ -152,7 +152,7 @@ static struct dr_datablock *to_datablock(struct dataring *dr,
* than or equal to the size of @dr_datablock.id. This ensures that there is
* always space in the data array for the @id of a "wrapping" data block.
*/
-static void to_db_size(unsigned int *size)
+static void to_db_size(unsigned long *size)
{
*size += sizeof(struct dr_datablock);
/* Alignment padding must be >= sizeof(dr_datablock.id). */
@@ -238,7 +238,7 @@ bool dataring_datablock_isvalid(struct dataring *dr, struct dr_desc *desc)
*
* Return: true if the size is legal for the data ringbuffer, otherwise false.
*/
-bool dataring_checksize(struct dataring *dr, unsigned int size)
+bool dataring_checksize(struct dataring *dr, unsigned long size)
{
if (size == 0)
return false;
@@ -445,7 +445,7 @@ static unsigned long _dataring_pop(struct dataring *dr,
* This will only fail if it was not possible to invalidate the tail data
* block (i.e. the @id of the tail data block was not yet set by its writer).
*/
-static bool get_new_lpos(struct dataring *dr, unsigned int size,
+static bool get_new_lpos(struct dataring *dr, unsigned long size,
unsigned long *begin_lpos_out,
unsigned long *next_lpos_out)
{
@@ -537,7 +537,7 @@ void dataring_desc_init(struct dr_desc *desc)
* This will only fail if it was not possible to invalidate the tail data
* block.
*/
-char *dataring_push(struct dataring *dr, unsigned int size,
+char *dataring_push(struct dataring *dr, unsigned long size,
struct dr_desc *desc, unsigned long id)
{
unsigned long begin_lpos;
diff --git a/kernel/printk/dataring.h b/kernel/printk/dataring.h
index 413ee95f4dd6..c566ce228abe 100644
--- a/kernel/printk/dataring.h
+++ b/kernel/printk/dataring.h
@@ -90,10 +90,10 @@ struct dataring {
void *getdesc_arg;
};

-bool dataring_checksize(struct dataring *dr, unsigned int size);
+bool dataring_checksize(struct dataring *dr, unsigned long size);

bool dataring_pop(struct dataring *dr);
-char *dataring_push(struct dataring *dr, unsigned int size,
+char *dataring_push(struct dataring *dr, unsigned long size,
struct dr_desc *desc, unsigned long id);

void dataring_datablock_setid(struct dataring *dr, struct dr_desc *desc,
diff --git a/kernel/printk/numlist.c b/kernel/printk/numlist.c
index d5e224dafc0c..16c6ffa74b01 100644
--- a/kernel/printk/numlist.c
+++ b/kernel/printk/numlist.c
@@ -108,7 +108,7 @@
*
* This function will fail if @id is not valid anytime during this function.
*/
-bool numlist_read(struct numlist *nl, unsigned long id, unsigned long *seq,
+bool numlist_read(struct numlist *nl, unsigned long id, u64 *seq,
unsigned long *next_id)
{
struct nl_node *n;
@@ -165,7 +165,7 @@ bool numlist_read(struct numlist *nl, unsigned long id, unsigned long *seq,
*
* Return: The ID of the tail node.
*/
-unsigned long numlist_read_tail(struct numlist *nl, unsigned long *seq,
+unsigned long numlist_read_tail(struct numlist *nl, u64 *seq,
unsigned long *next_id)
{
unsigned long tail_id;
@@ -201,8 +201,8 @@ unsigned long numlist_read_tail(struct numlist *nl, unsigned long *seq,
void numlist_push(struct numlist *nl, struct nl_node *n, unsigned long id)
{
unsigned long head_id;
- unsigned long seq;
unsigned long r;
+ u64 seq;

/*
* bA:
diff --git a/kernel/printk/numlist.h b/kernel/printk/numlist.h
index cdc3b21e6597..d4595fb9a3e9 100644
--- a/kernel/printk/numlist.h
+++ b/kernel/printk/numlist.h
@@ -20,7 +20,7 @@
*/
struct nl_node {
/* private */
- unsigned long seq;
+ u64 seq;
unsigned long next_id;
};

@@ -64,9 +64,9 @@ struct numlist {
void numlist_push(struct numlist *nl, struct nl_node *n, unsigned long id);
struct nl_node *numlist_pop(struct numlist *nl);

-unsigned long numlist_read_tail(struct numlist *nl, unsigned long *seq,
+unsigned long numlist_read_tail(struct numlist *nl, u64 *seq,
unsigned long *next_id);
-bool numlist_read(struct numlist *nl, unsigned long id, unsigned long *seq,
+bool numlist_read(struct numlist *nl, unsigned long id, u64 *seq,
unsigned long *next_id);

#endif /* _KERNEL_PRINTK_NUMLIST_H */
diff --git a/kernel/printk/ringbuffer.c b/kernel/printk/ringbuffer.c
index 9be841761ea2..053622151447 100644
--- a/kernel/printk/ringbuffer.c
+++ b/kernel/printk/ringbuffer.c
@@ -416,7 +416,7 @@ static bool assign_desc(struct prb_reserved_entry *e)
* * -ENOMEM: failed to reserve data (invalid descriptor committed)
*/
char *prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb,
- unsigned int size)
+ unsigned long size)
{
struct prb_desc *d;
unsigned long id;
@@ -567,7 +567,7 @@ EXPORT_SYMBOL(prb_iter_init);
*/
static void reset_iter(struct prb_iterator *iter)
{
- unsigned long last_seq;
+ u64 last_seq;

iter->next_id = numlist_read_tail(&iter->rb->nl, &last_seq, NULL);

@@ -650,9 +650,9 @@ int prb_iter_next_valid_entry(struct prb_iterator *iter)
struct dr_desc desc;
struct prb_desc *d;
struct nl_node *n;
- unsigned long seq;
unsigned long id;
int size;
+ u64 seq;

if (!setup_next(nl, iter))
return 0;
diff --git a/kernel/printk/ringbuffer.h b/kernel/printk/ringbuffer.h
index 698d2328ea9e..ec7bb21abac2 100644
--- a/kernel/printk/ringbuffer.h
+++ b/kernel/printk/ringbuffer.h
@@ -97,9 +97,9 @@ struct prb_reserved_entry {
*/
struct prb_entry {
/* public */
- unsigned long seq;
- char *buffer;
- int buffer_size;
+ u64 seq;
+ char *buffer;
+ int buffer_size;
};

/**
@@ -125,13 +125,13 @@ struct prb_iterator {
struct prb_entry *e;

unsigned long last_id;
- unsigned long last_seq;
+ u64 last_seq;
unsigned long next_id;
};

/* writer interface */
char *prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb,
- unsigned int size);
+ unsigned long size);
void prb_commit(struct prb_reserved_entry *e);

/* reader interface */
diff --git a/kernel/printk/test_prb.c b/kernel/printk/test_prb.c
index 77d298b6990a..0157bbdf051f 100644
--- a/kernel/printk/test_prb.c
+++ b/kernel/printk/test_prb.c
@@ -38,8 +38,8 @@ static void dump_rb(struct printk_ringbuffer *rb)
{
DECLARE_PRINTKRB_ENTRY(entry, 160);
DECLARE_PRINTKRB_ITER(iter, rb, &entry);
- unsigned long last_seq = 0;
struct rbdata *dat;
+ u64 last_seq = 0;
char buf[160];
int len;

@@ -47,7 +47,7 @@ static void dump_rb(struct printk_ringbuffer *rb)

prb_for_each_entry_continue(&iter, len) {
if (entry.seq - last_seq != 1) {
- trace_printk("LOST %lu\n",
+ trace_printk("LOST %llu\n",
entry.seq - (last_seq + 1));
}
last_seq = entry.seq;
@@ -56,7 +56,7 @@ static void dump_rb(struct printk_ringbuffer *rb)

snprintf(buf, sizeof(buf), "%s", dat->text);
buf[sizeof(buf) - 1] = 0;
- trace_printk("seq=%lu len=%d textlen=%d dataval=%s\n",
+ trace_printk("seq=%llu len=%d textlen=%d dataval=%s\n",
entry.seq, len, dat->len, buf);
}

@@ -112,11 +112,11 @@ static int prbtest_reader(void *data)
DECLARE_PRINTKRB_ENTRY(entry, 160);
DECLARE_PRINTKRB_ITER(iter, &test_rb, &entry);
unsigned long total_lost = 0;
- unsigned long last_seq = 0;
unsigned long max_lost = 0;
unsigned long count = 0;
struct rbdata *dat;
int did_sched = 1;
+ u64 last_seq = 0;
int len;

pr_err("prbtest: start thread %lu (reader)\n", num);
@@ -126,7 +126,7 @@ static int prbtest_reader(void *data)
if (entry.seq < last_seq) {
WRITE_ONCE(halt_test, 1);
trace_printk(
- "reader%lu invalid seq %lu -> %lu\n",
+ "reader%lu invalid seq %llu -> %llu\n",
num, last_seq, entry.seq);
goto out;
}
@@ -145,7 +145,7 @@ static int prbtest_reader(void *data)
if (len != dat->len || len >= 160) {
WRITE_ONCE(halt_test, 1);
trace_printk(
- "reader%lu invalid len for %lu (%d<->%d)\n",
+ "reader%lu invalid len for %llu (%d<->%d)\n",
num, entry.seq, len, dat->len);
goto out;
}
@@ -172,7 +172,7 @@ static int prbtest_reader(void *data)
}
out:
pr_err(
- "reader%lu: total_lost=%lu max_lost=%lu total_read=%lu seq=%lu\n",
+ "reader%lu: total_lost=%lu max_lost=%lu total_read=%lu seq=%llu\n",
num, total_lost, max_lost, count, entry.seq);
pr_err("prbtest: end thread %lu (reader)\n", num);

--
2.20.1