From 7c13750947dd4b7d919e99762f235837c3a0f6c5 Mon Sep 17 00:00:00 2001 From: John Ogness Date: Wed, 7 Feb 2024 14:46:52 +0106 Subject: [PATCH] printk: Use prb_first_seq() as base for 32bit seq macros [ Upstream commit 90ad525c2d9a8a6591ab822234a94b82871ef8e0 ] Note: This change only applies to 32bit architectures. On 64bit architectures the macros are NOPs. Currently prb_next_seq() is used as the base for the 32bit seq macros __u64seq_to_ulseq() and __ulseq_to_u64seq(). However, in a follow-up commit, prb_next_seq() will need to make use of the 32bit seq macros. Use prb_first_seq() as the base for the 32bit seq macros instead because it is guaranteed to return 64bit sequence numbers without relying on any 32bit seq macros. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20240207134103.1357162-4-john.ogness@linutronix.de Signed-off-by: Petr Mladek Signed-off-by: Sasha Levin --- kernel/printk/printk_ringbuffer.c | 2 +- kernel/printk/printk_ringbuffer.h | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index 3d98232902cf..f5a8bb606fe5 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -1931,7 +1931,7 @@ static int prb_read(struct printk_ringbuffer *rb, u64 seq, } /* Get the sequence number of the tail descriptor. */ -static u64 prb_first_seq(struct printk_ringbuffer *rb) +u64 prb_first_seq(struct printk_ringbuffer *rb) { struct prb_desc_ring *desc_ring = &rb->desc_ring; enum desc_state d_state; diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h index d72938772690..cb887489d00f 100644 --- a/kernel/printk/printk_ringbuffer.h +++ b/kernel/printk/printk_ringbuffer.h @@ -378,6 +378,7 @@ bool prb_read_valid(struct printk_ringbuffer *rb, u64 seq, bool prb_read_valid_info(struct printk_ringbuffer *rb, u64 seq, struct printk_info *info, unsigned int *line_count); +u64 prb_first_seq(struct printk_ringbuffer *rb); u64 prb_first_valid_seq(struct printk_ringbuffer *rb); u64 prb_next_seq(struct printk_ringbuffer *rb); u64 prb_next_reserve_seq(struct printk_ringbuffer *rb); @@ -393,12 +394,12 @@ u64 prb_next_reserve_seq(struct printk_ringbuffer *rb); static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq) { + u64 rb_first_seq = prb_first_seq(rb); u64 seq; - u64 rb_next_seq; /* * The provided sequence is only the lower 32 bits of the ringbuffer - * sequence. It needs to be expanded to 64bit. Get the next sequence + * sequence. It needs to be expanded to 64bit. Get the first sequence * number from the ringbuffer and fold it. * * Having a 32bit representation in the console is sufficient. @@ -407,8 +408,7 @@ static inline u64 __ulseq_to_u64seq(struct printk_ringbuffer *rb, u32 ulseq) * * Also the access to the ring buffer is always safe. */ - rb_next_seq = prb_next_seq(rb); - seq = rb_next_seq - (s32)((u32)rb_next_seq - ulseq); + seq = rb_first_seq - (s32)((u32)rb_first_seq - ulseq); return seq; }