diff options
Diffstat (limited to 'fs/pstore/platform.c')
-rw-r--r-- | fs/pstore/platform.c | 76 |
1 files changed, 31 insertions, 45 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 2b21d180157c..8af9efa0ca0a 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -129,26 +129,27 @@ static const char *get_reason_str(enum kmsg_dump_reason reason) } } -bool pstore_cannot_block_path(enum kmsg_dump_reason reason) +/* + * Should pstore_dump() wait for a concurrent pstore_dump()? If + * not, the current pstore_dump() will report a failure to dump + * and return. + */ +static bool pstore_cannot_wait(enum kmsg_dump_reason reason) { - /* - * In case of NMI path, pstore shouldn't be blocked - * regardless of reason. - */ + /* In NMI path, pstore shouldn't block regardless of reason. */ if (in_nmi()) return true; switch (reason) { /* In panic case, other cpus are stopped by smp_send_stop(). */ case KMSG_DUMP_PANIC: - /* Emergency restart shouldn't be blocked by spin lock. */ + /* Emergency restart shouldn't be blocked. */ case KMSG_DUMP_EMERG: return true; default: return false; } } -EXPORT_SYMBOL_GPL(pstore_cannot_block_path); #ifdef CONFIG_PSTORE_ZLIB_COMPRESS /* Derived from logfs_compress() */ @@ -499,23 +500,23 @@ static void pstore_dump(struct kmsg_dumper *dumper, unsigned long total = 0; const char *why; unsigned int part = 1; - unsigned long flags = 0; - int is_locked; int ret; why = get_reason_str(reason); - if (pstore_cannot_block_path(reason)) { - is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags); - if (!is_locked) { - pr_err("pstore dump routine blocked in %s path, may corrupt error record\n" - , in_nmi() ? "NMI" : why); + if (down_trylock(&psinfo->buf_lock)) { + /* Failed to acquire lock: give up if we cannot wait. */ + if (pstore_cannot_wait(reason)) { + pr_err("dump skipped in %s path: may corrupt error record\n", + in_nmi() ? "NMI" : why); + return; + } + if (down_interruptible(&psinfo->buf_lock)) { + pr_err("could not grab semaphore?!\n"); return; } - } else { - spin_lock_irqsave(&psinfo->buf_lock, flags); - is_locked = 1; } + oopscount++; while (total < kmsg_bytes) { char *dst; @@ -532,7 +533,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, record.part = part; record.buf = psinfo->buf; - if (big_oops_buf && is_locked) { + if (big_oops_buf) { dst = big_oops_buf; dst_size = big_oops_buf_sz; } else { @@ -550,7 +551,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, dst_size, &dump_size)) break; - if (big_oops_buf && is_locked) { + if (big_oops_buf) { zipped_len = pstore_compress(dst, psinfo->buf, header_size + dump_size, psinfo->bufsize); @@ -573,8 +574,8 @@ static void pstore_dump(struct kmsg_dumper *dumper, total += record.size; part++; } - if (is_locked) - spin_unlock_irqrestore(&psinfo->buf_lock, flags); + + up(&psinfo->buf_lock); } static struct kmsg_dumper pstore_dumper = { @@ -597,31 +598,14 @@ static void pstore_unregister_kmsg(void) #ifdef CONFIG_PSTORE_CONSOLE static void pstore_console_write(struct console *con, const char *s, unsigned c) { - const char *e = s + c; + struct pstore_record record; - while (s < e) { - struct pstore_record record; - unsigned long flags; - - pstore_record_init(&record, psinfo); - record.type = PSTORE_TYPE_CONSOLE; - - if (c > psinfo->bufsize) - c = psinfo->bufsize; + pstore_record_init(&record, psinfo); + record.type = PSTORE_TYPE_CONSOLE; - if (oops_in_progress) { - if (!spin_trylock_irqsave(&psinfo->buf_lock, flags)) - break; - } else { - spin_lock_irqsave(&psinfo->buf_lock, flags); - } - record.buf = (char *)s; - record.size = c; - psinfo->write(&record); - spin_unlock_irqrestore(&psinfo->buf_lock, flags); - s += c; - c = e - s; - } + record.buf = (char *)s; + record.size = c; + psinfo->write(&record); } static struct console pstore_console = { @@ -710,6 +694,7 @@ int pstore_register(struct pstore_info *psi) psi->write_user = pstore_write_user_compat; psinfo = psi; mutex_init(&psinfo->read_mutex); + sema_init(&psinfo->buf_lock, 1); spin_unlock(&pstore_lock); if (owner && !try_module_get(owner)) { @@ -717,7 +702,8 @@ int pstore_register(struct pstore_info *psi) return -EINVAL; } - allocate_buf_for_compression(); + if (psi->flags & PSTORE_FLAGS_DMESG) + allocate_buf_for_compression(); if (pstore_is_mounted()) pstore_get_records(0); |