Merge branch 'rework/prb-fixes' into for-linus (add9d911) · Commits · git / linux-net

kernel/printk/printk_ringbuffer.c

+15 −12

Original line number	Diff line number	Diff line
		@@ -14,7 +14,7 @@
		*
		* Data Structure
		* --------------
		* The printk_ringbuffer is made up of 3 internal ringbuffers:
		* The printk_ringbuffer is made up of 2 internal ringbuffers:
		*
		* desc_ring
		* A ring of descriptors and their meta data (such as sequence number,
		@@ -224,7 +224,7 @@
		*
		* prb_rec_init_rd(&r, &info, &text_buf[0], sizeof(text_buf));
		*
		* prb_for_each_record(0, &test_rb, &seq, &r) {
		* prb_for_each_record(0, &test_rb, seq, &r) {
		* if (info.seq != seq)
		* pr_warn("lost %llu records\n", info.seq - seq);
		*
		@@ -1302,23 +1302,26 @@ static const char get_data(struct prb_data_ring data_ring,
		return NULL;
		}

		/* Sanity check. Data-less blocks were handled earlier. */
		if (WARN_ON_ONCE(!data_check_size(data_ring, data_size) \|\| !data_size))
		return NULL;

		/* A valid data block will always be aligned to the ID size. */
		if (WARN_ON_ONCE(blk_lpos->begin != ALIGN(blk_lpos->begin, sizeof(db->id))) \|\|
		WARN_ON_ONCE(blk_lpos->next != ALIGN(blk_lpos->next, sizeof(db->id)))) {
		return NULL;
		}

		/* A valid data block will always have at least an ID. */
		if (WARN_ON_ONCE(*data_size < sizeof(db->id)))
		/*
		* A regular data block will always have an ID and at least
		* 1 byte of data. Data-less blocks were handled earlier.
		*/
		if (WARN_ON_ONCE(*data_size <= sizeof(db->id)))
		return NULL;

		/* Subtract block ID space from size to reflect data size. */
		*data_size -= sizeof(db->id);

		/* Sanity check the max size of the regular data block. */
		if (WARN_ON_ONCE(!data_check_size(data_ring, *data_size)))
		return NULL;

		return &db->data[0];
		}

		@@ -1365,7 +1368,7 @@ static struct prb_desc desc_reopen_last(struct prb_desc_ring desc_ring,
		*
		* WMB from _prb_commit:A to _prb_commit:B
		* matching
		* MB If desc_reopen_last:A to prb_reserve_in_last:A
		* MB from desc_reopen_last:A to prb_reserve_in_last:A
		*/
		if (!atomic_long_try_cmpxchg(&d->state_var, &prev_state_val,
		DESC_SV(id, desc_reserved))) { /* LMM(desc_reopen_last:A) */
		@@ -1770,9 +1773,9 @@ static void _prb_commit(struct prb_reserved_entry *e, unsigned long state_val)
		*
		* Relies on:
		*
		* MB _prb_commit:B to prb_commit:A
		* MB from _prb_commit:B to prb_commit:A
		* matching
		* MB desc_reserve:D to desc_make_final:A
		* MB from desc_reserve:D to desc_make_final:A
		*/
		if (!atomic_long_try_cmpxchg(&d->state_var, &prev_state_val,
		DESC_SV(e->id, state_val))) { /* LMM(_prb_commit:B) */
		@@ -2035,7 +2038,7 @@ u64 prb_first_seq(struct printk_ringbuffer *rb)
		*
		* MB from desc_push_tail:B to desc_reserve:F
		* matching
		* RMB prb_first_seq:B to prb_first_seq:A
		* RMB from prb_first_seq:B to prb_first_seq:A
		*/
		smp_rmb(); /* LMM(prb_first_seq:C) */
		}

kernel/printk/printk_ringbuffer.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -127,7 +127,7 @@ enum desc_state {
		};

		#define _DATA_SIZE(sz_bits) (1UL << (sz_bits))
		#define _DESCS_COUNT(ct_bits) (1U << (ct_bits))
		#define _DESCS_COUNT(ct_bits) (1UL << (ct_bits))
		#define DESC_SV_BITS BITS_PER_LONG
		#define DESC_FLAGS_SHIFT (DESC_SV_BITS - 2)
		#define DESC_FLAGS_MASK (3UL << DESC_FLAGS_SHIFT)
		@@ -388,7 +388,7 @@ for ((s) = from; prb_read_valid(rb, s, r); (s) = (r)->info->seq + 1)
		*
		* This is a macro for conveniently iterating over a ringbuffer.
		* Note that @s may not be the sequence number of the record on each
		* iteration. For the sequence number, @r->info->seq should be checked.
		* iteration. For the sequence number, @i->seq should be checked.
		*
		* Context: Any context.
		*/