From: John Ogness <john.ogness@linutronix.de> To: Petr Mladek <pmladek@suse.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>, Sergey Senozhatsky <sergey.senozhatsky@gmail.com>, Steven Rostedt <rostedt@goodmis.org>, Linus Torvalds <torvalds@linux-foundation.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Thomas Gleixner <tglx@linutronix.de>, Peter Zijlstra <peterz@infradead.org>, Andrea Parri <parri.andrea@gmail.com>, Paul McKenney <paulmck@kernel.org>, kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH next v3 5/8] printk: ringbuffer: clear initial reserved fields Date: Mon, 31 Aug 2020 03:16:55 +0206 [thread overview] Message-ID: <20200831011058.6286-6-john.ogness@linutronix.de> (raw) In-Reply-To: <20200831011058.6286-1-john.ogness@linutronix.de> prb_reserve() will set some meta data values and leave others uninitialized (or rather, containing the values of the previous wrap). Simplify the API by always clearing out all the fields. Only the sequence number is filled in. The caller is now responsible for filling in the rest of the meta data fields. In particular, for correctly filling in text and dict lengths. Signed-off-by: John Ogness <john.ogness@linutronix.de> --- kernel/printk/printk.c | 7 ++++++- kernel/printk/printk_ringbuffer.c | 29 +++++++++++++++++++---------- 2 files changed, 25 insertions(+), 11 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index ad8d1dfe5fbe..7e7d596c8878 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -520,8 +520,11 @@ static int log_store(u32 caller_id, int facility, int level, memcpy(&r.text_buf[0], text, text_len); if (trunc_msg_len) memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len); - if (r.dict_buf) + r.info->text_len = text_len + trunc_msg_len; + if (r.dict_buf) { memcpy(&r.dict_buf[0], dict, dict_len); + r.info->dict_len = dict_len; + } r.info->facility = facility; r.info->level = level & 7; r.info->flags = flags & 0x1f; @@ -1078,9 +1081,11 @@ static unsigned int __init add_to_rb(struct printk_ringbuffer *rb, return 0; memcpy(&dest_r.text_buf[0], &r->text_buf[0], dest_r.text_buf_size); + dest_r.info->text_len = r->info->text_len; if (dest_r.dict_buf) { memcpy(&dest_r.dict_buf[0], &r->dict_buf[0], dest_r.dict_buf_size); + dest_r.info->dict_len = r->info->dict_len; } dest_r.info->facility = r->info->facility; dest_r.info->level = r->info->level; diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index d66718e74aae..da54d4fadf96 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -146,10 +146,13 @@ * * if (prb_reserve(&e, &test_rb, &r)) { * snprintf(r.text_buf, r.text_buf_size, "%s", textstr); + * r.info->text_len = strlen(textstr); * * // dictionary allocation may have failed - * if (r.dict_buf) + * if (r.dict_buf) { * snprintf(r.dict_buf, r.dict_buf_size, "%s", dictstr); + * r.info->dict_len = strlen(dictstr); + * } * * r.info->ts_nsec = local_clock(); * @@ -1125,9 +1128,9 @@ static const char *get_data(struct prb_data_ring *data_ring, * @dict_buf_size is set to 0. Writers must check this before writing to * dictionary space. * - * @info->text_len and @info->dict_len will already be set to @text_buf_size - * and @dict_buf_size, respectively. If dictionary space reservation fails, - * @info->dict_len is set to 0. + * Important: @info->text_len and @info->dict_len need to be set correctly by + * the writer in order for data to be readable and/or extended. + * Their values are initialized to 0. */ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, struct printk_record *r) @@ -1159,6 +1162,18 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, d = to_desc(desc_ring, id); + /* + * Clear all @info fields except for @seq, which is used to determine + * the new sequence number. The writer must fill in new values. + */ + d->info.ts_nsec = 0; + d->info.text_len = 0; + d->info.dict_len = 0; + d->info.facility = 0; + d->info.flags = 0; + d->info.level = 0; + d->info.caller_id = 0; + /* * Set the @e fields here so that prb_commit() can be used if * text data allocation fails. @@ -1186,8 +1201,6 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, &d->text_blk_lpos, id); /* If text data allocation fails, a data-less record is committed. */ if (r->text_buf_size && !r->text_buf) { - d->info.text_len = 0; - d->info.dict_len = 0; prb_commit(e); /* prb_commit() re-enabled interrupts. */ goto fail; @@ -1204,10 +1217,6 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, r->info = &d->info; - /* Set default values for the sizes. */ - d->info.text_len = r->text_buf_size; - d->info.dict_len = r->dict_buf_size; - /* Record full text space used by record. */ e->text_space = space_used(&rb->text_data_ring, &d->text_blk_lpos); -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: John Ogness <john.ogness@linutronix.de> To: Petr Mladek <pmladek@suse.com> Cc: Andrea Parri <parri.andrea@gmail.com>, Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>, Paul McKenney <paulmck@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>, Sergey Senozhatsky <sergey.senozhatsky@gmail.com>, Thomas Gleixner <tglx@linutronix.de>, Linus Torvalds <torvalds@linux-foundation.org> Subject: [PATCH next v3 5/8] printk: ringbuffer: clear initial reserved fields Date: Mon, 31 Aug 2020 03:16:55 +0206 [thread overview] Message-ID: <20200831011058.6286-6-john.ogness@linutronix.de> (raw) In-Reply-To: <20200831011058.6286-1-john.ogness@linutronix.de> prb_reserve() will set some meta data values and leave others uninitialized (or rather, containing the values of the previous wrap). Simplify the API by always clearing out all the fields. Only the sequence number is filled in. The caller is now responsible for filling in the rest of the meta data fields. In particular, for correctly filling in text and dict lengths. Signed-off-by: John Ogness <john.ogness@linutronix.de> --- kernel/printk/printk.c | 7 ++++++- kernel/printk/printk_ringbuffer.c | 29 +++++++++++++++++++---------- 2 files changed, 25 insertions(+), 11 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index ad8d1dfe5fbe..7e7d596c8878 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -520,8 +520,11 @@ static int log_store(u32 caller_id, int facility, int level, memcpy(&r.text_buf[0], text, text_len); if (trunc_msg_len) memcpy(&r.text_buf[text_len], trunc_msg, trunc_msg_len); - if (r.dict_buf) + r.info->text_len = text_len + trunc_msg_len; + if (r.dict_buf) { memcpy(&r.dict_buf[0], dict, dict_len); + r.info->dict_len = dict_len; + } r.info->facility = facility; r.info->level = level & 7; r.info->flags = flags & 0x1f; @@ -1078,9 +1081,11 @@ static unsigned int __init add_to_rb(struct printk_ringbuffer *rb, return 0; memcpy(&dest_r.text_buf[0], &r->text_buf[0], dest_r.text_buf_size); + dest_r.info->text_len = r->info->text_len; if (dest_r.dict_buf) { memcpy(&dest_r.dict_buf[0], &r->dict_buf[0], dest_r.dict_buf_size); + dest_r.info->dict_len = r->info->dict_len; } dest_r.info->facility = r->info->facility; dest_r.info->level = r->info->level; diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index d66718e74aae..da54d4fadf96 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -146,10 +146,13 @@ * * if (prb_reserve(&e, &test_rb, &r)) { * snprintf(r.text_buf, r.text_buf_size, "%s", textstr); + * r.info->text_len = strlen(textstr); * * // dictionary allocation may have failed - * if (r.dict_buf) + * if (r.dict_buf) { * snprintf(r.dict_buf, r.dict_buf_size, "%s", dictstr); + * r.info->dict_len = strlen(dictstr); + * } * * r.info->ts_nsec = local_clock(); * @@ -1125,9 +1128,9 @@ static const char *get_data(struct prb_data_ring *data_ring, * @dict_buf_size is set to 0. Writers must check this before writing to * dictionary space. * - * @info->text_len and @info->dict_len will already be set to @text_buf_size - * and @dict_buf_size, respectively. If dictionary space reservation fails, - * @info->dict_len is set to 0. + * Important: @info->text_len and @info->dict_len need to be set correctly by + * the writer in order for data to be readable and/or extended. + * Their values are initialized to 0. */ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, struct printk_record *r) @@ -1159,6 +1162,18 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, d = to_desc(desc_ring, id); + /* + * Clear all @info fields except for @seq, which is used to determine + * the new sequence number. The writer must fill in new values. + */ + d->info.ts_nsec = 0; + d->info.text_len = 0; + d->info.dict_len = 0; + d->info.facility = 0; + d->info.flags = 0; + d->info.level = 0; + d->info.caller_id = 0; + /* * Set the @e fields here so that prb_commit() can be used if * text data allocation fails. @@ -1186,8 +1201,6 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, &d->text_blk_lpos, id); /* If text data allocation fails, a data-less record is committed. */ if (r->text_buf_size && !r->text_buf) { - d->info.text_len = 0; - d->info.dict_len = 0; prb_commit(e); /* prb_commit() re-enabled interrupts. */ goto fail; @@ -1204,10 +1217,6 @@ bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, r->info = &d->info; - /* Set default values for the sizes. */ - d->info.text_len = r->text_buf_size; - d->info.dict_len = r->dict_buf_size; - /* Record full text space used by record. */ e->text_space = space_used(&rb->text_data_ring, &d->text_blk_lpos); -- 2.20.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2020-08-31 1:11 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-31 1:10 [PATCH next v3 0/8] printk: reimplement LOG_CONT handling John Ogness 2020-08-31 1:10 ` John Ogness 2020-08-31 1:10 ` [PATCH next v3 1/8] printk: ringbuffer: rename DESC_COMMITTED_MASK flag John Ogness 2020-08-31 1:10 ` John Ogness 2020-08-31 1:10 ` [PATCH next v3 2/8] printk: ringbuffer: change representation of reusable John Ogness 2020-08-31 1:10 ` John Ogness 2020-08-31 1:10 ` [PATCH next v3 3/8] printk: ringbuffer: relocate get_data() John Ogness 2020-08-31 1:10 ` John Ogness 2020-08-31 1:10 ` [PATCH next v3 4/8] printk: ringbuffer: add BLK_DATALESS() macro John Ogness 2020-08-31 1:10 ` John Ogness 2020-08-31 1:10 ` John Ogness [this message] 2020-08-31 1:10 ` [PATCH next v3 5/8] printk: ringbuffer: clear initial reserved fields John Ogness 2020-09-01 14:33 ` Petr Mladek 2020-09-01 14:33 ` Petr Mladek 2020-08-31 1:10 ` [PATCH next v3 6/8] printk: ringbuffer: add finalization/extension support John Ogness 2020-08-31 1:10 ` John Ogness 2020-08-31 12:54 ` John Ogness 2020-08-31 12:54 ` John Ogness 2020-09-02 10:52 ` state names: vas: " Petr Mladek 2020-09-02 10:52 ` Petr Mladek 2020-09-02 11:20 ` John Ogness 2020-09-02 11:20 ` John Ogness 2020-09-02 12:39 ` Petr Mladek 2020-09-02 12:39 ` Petr Mladek 2020-09-02 10:58 ` Petr Mladek 2020-09-02 10:58 ` Petr Mladek 2020-09-02 12:21 ` misc: was: " Petr Mladek 2020-09-02 12:21 ` Petr Mladek 2020-08-31 1:10 ` [PATCH next v3 7/8] printk: reimplement log_cont using record extension John Ogness 2020-08-31 1:10 ` John Ogness 2020-09-02 13:38 ` Petr Mladek 2020-09-02 13:38 ` Petr Mladek 2020-08-31 1:10 ` [PATCH next v3 8/8] scripts/gdb: support printk finalized records John Ogness 2020-08-31 1:10 ` John Ogness
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