Hello, Here is v2 of a series to remove @logbuf_lock, exposing the ringbuffer locklessly to both readers and writers. v1 is here [0].
Since @logbuf_lock was protecting much more than just the ringbuffer, this series clarifies and cleans up the various protections using comments, lockless accessors, atomic types, and a new finer-grained @syslog_log. Changes since v1: - handle the syslog_print_all() size calculation issue in a separate patch (patch 1) - use a local printk_info for find_first_fitting_seq() - define CONSOLE_LOG_MAX in printk.c instead of printk.h since it is not used outside of printk.c - increase CONSOLE_LOG_MAX to 4096 to support long multi-line records - add a wrapper function read_syslog_seq_irq() for getting a consistent @syslog_seq value (only used in do_syslog()) - drop the "hv: synchronize kmsg_dumper" patch - in "remove logbuf_lock" only change to safe buffer usage - fixup safe buffer usage and redundance in separate patches (patches 13 and 14) - update comments and commit messages as requested John Ogness [0] https://lkml.kernel.org/r/20210126211551.26536-1-john.ogn...@linutronix.de John Ogness (14): printk: limit second loop of syslog_print_all printk: kmsg_dump: remove unused fields printk: refactor kmsg_dump_get_buffer() printk: consolidate kmsg_dump_get_buffer/syslog_print_all code printk: introduce CONSOLE_LOG_MAX for improved multi-line support printk: use seqcount_latch for clear_seq printk: use atomic64_t for devkmsg_user.seq printk: add syslog_lock printk: introduce a kmsg_dump iterator um: synchronize kmsg_dumper printk: remove logbuf_lock printk: kmsg_dump: remove _nolock() variants printk: kmsg_dump: use kmsg_dump_rewind printk: console: remove unnecessary safe buffer usage arch/powerpc/kernel/nvram_64.c | 12 +- arch/powerpc/platforms/powernv/opal-kmsg.c | 3 +- arch/powerpc/xmon/xmon.c | 6 +- arch/um/kernel/kmsg_dump.c | 13 +- drivers/hv/vmbus_drv.c | 5 +- drivers/mtd/mtdoops.c | 5 +- fs/pstore/platform.c | 5 +- include/linux/kmsg_dump.h | 52 +-- kernel/debug/kdb/kdb_main.c | 10 +- kernel/printk/internal.h | 4 +- kernel/printk/printk.c | 454 +++++++++++---------- kernel/printk/printk_safe.c | 29 +- 12 files changed, 298 insertions(+), 300 deletions(-) -- 2.20.1
