user/sven/linux.git/kernel/printk, branch v5.13.17

printk: Move EXPORT_SYMBOL() closer to vprintk definition

2021-06-16T08:42:19Z

Commit 28e1745b9fa2 ("printk: rename vprintk_func to vprintk") while improving readability by removing vprintk indirection, inadvertently placed the EXPORT_SYMBOL() for the newly renamed function at the end of the file. For reader sanity, and as is convention move the EXPORT_SYMBOL() declaration just after the end of the function. Fixes: 28e1745b9fa2 ("printk: rename vprintk_func to vprintk") Signed-off-by: Punit Agrawal Acked-by: Rasmus Villemoes Acked-by: Sergey Senozhatsky Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210614235635.887365-1-punitagrawal@gmail.com

kernel/printk.c: Fixed mundane typos

2021-03-30T13:34:17Z

s/sempahore/semaphore/ s/exacly/exactly/ s/unregistred/unregistered/ s/interation/iteration/ Signed-off-by: Bhaskar Chowdhury Reviewed-by: Petr Mladek [pmladek@suse.com: Removed 4th hunk. The string has already been removed in the meantime.] Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210328043932.8310-1-unixbhaskar@gmail.com

printk: rename vprintk_func to vprintk

2021-03-30T13:21:18Z

The printk code is already hard enough to understand. Remove an unnecessary indirection by renaming vprintk_func to vprintk (adding the asmlinkage annotation), and removing the vprintk definition from printk.c. That way, printk is implemented in terms of vprintk as one would expect, and there's no "vprintk_func, what's that? Some function pointer that gets set where?" The declaration of vprintk in linux/printk.h already has the __printf(1,0) attribute, there's no point repeating that with the definition - it's for diagnostics in callers. linux/printk.h already contains a static inline {return 0;} definition of vprintk when !CONFIG_PRINTK. Since the corresponding stub definition of vprintk_func was not marked "static inline", any translation unit including internal.h would get a definition of vprintk_func - it just so happens that for !CONFIG_PRINTK, there is precisely one such TU, namely printk.c. Had there been more, it would be a link error; now it's just a silly waste of a few bytes of .text, which one must assume are rather precious to anyone disabling PRINTK. $ objdump -dr kernel/printk/printk.o 00000330 : 330: 31 c0 xor %eax,%eax 332: c3 ret 333: 8d b4 26 00 00 00 00 lea 0x0(%esi,%eiz,1),%esi 33a: 8d b6 00 00 00 00 lea 0x0(%esi),%esi Signed-off-by: Rasmus Villemoes Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210323144201.486050-1-linux@rasmusvillemoes.dk

printk: console: remove unnecessary safe buffer usage

2021-03-08T10:43:38Z

Upon registering a console, safe buffers are activated when setting up the sequence number to replay the log. However, these are already protected by @console_sem and @syslog_lock. Remove the unnecessary safe buffer usage. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-16-john.ogness@linutronix.de

printk: kmsg_dump: remove _nolock() variants

2021-03-08T10:43:35Z

kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is no need for _nolock() variants. Remove these functions and switch all callers of the _nolock() variants. The functions without _nolock() were chosen because they are already exported to kernel modules. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-15-john.ogness@linutronix.de

printk: remove logbuf_lock

2021-03-08T10:43:32Z

Since the ringbuffer is lockless, there is no need for it to be protected by @logbuf_lock. Remove @logbuf_lock. @console_seq, @exclusive_console_stop_seq, @console_dropped are protected by @console_lock. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-14-john.ogness@linutronix.de

printk: introduce a kmsg_dump iterator

2021-03-08T10:43:27Z

Rather than storing the iterator information in the registered kmsg_dumper structure, create a separate iterator structure. The kmsg_dump_iter structure can reside on the stack of the caller, thus allowing lockless use of the kmsg_dump functions. Update code that accesses the kernel logs using the kmsg_dumper structure to use the new kmsg_dump_iter structure. For kmsg_dumpers, this also means adding a call to kmsg_dump_rewind() to initialize the iterator. All this is in preparation for removal of @logbuf_lock. Signed-off-by: John Ogness Reviewed-by: Kees Cook # pstore Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de

printk: kmsg_dumper: remove @active field

2021-03-08T10:43:23Z

All 6 kmsg_dumpers do not benefit from the @active flag: (provide their own synchronization) - arch/powerpc/kernel/nvram_64.c - arch/um/kernel/kmsg_dump.c - drivers/mtd/mtdoops.c - fs/pstore/platform.c (only dump on KMSG_DUMP_PANIC, which does not require synchronization) - arch/powerpc/platforms/powernv/opal-kmsg.c - drivers/hv/vmbus_drv.c The other 2 kmsg_dump users also do not rely on @active: (hard-code @active to always be true) - arch/powerpc/xmon/xmon.c - kernel/debug/kdb/kdb_main.c Therefore, @active can be removed. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-12-john.ogness@linutronix.de

printk: add syslog_lock

2021-03-08T10:43:20Z

The global variables @syslog_seq, @syslog_partial, @syslog_time and write access to @clear_seq are protected by @logbuf_lock. Once @logbuf_lock is removed, these variables will need their own synchronization method. Introduce @syslog_lock for this purpose. @syslog_lock is a raw_spin_lock for now. This simplifies the transition to removing @logbuf_lock. Once @logbuf_lock and the safe buffers are removed, @syslog_lock can change to spin_lock. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-11-john.ogness@linutronix.de

printk: use atomic64_t for devkmsg_user.seq

2021-03-08T10:43:18Z

@user->seq is indirectly protected by @logbuf_lock. Once @logbuf_lock is removed, @user->seq will be no longer safe from an atomicity point of view. In preparation for the removal of @logbuf_lock, change it to atomic64_t to provide this safety. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210303101528.29901-10-john.ogness@linutronix.de