diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c index 22e9d281324da..e7d4ce6964ae9 100644 --- a/arch/powerpc/kernel/nvram_64.c +++ b/arch/powerpc/kernel/nvram_64.c @@ -563,8 +563,6 @@ static int nvram_pstore_init(void) nvram_pstore_info.buf = oops_data; nvram_pstore_info.bufsize = oops_data_sz; - spin_lock_init(&nvram_pstore_info.buf_lock); - rc = pstore_register(&nvram_pstore_info); if (rc && (rc != -EPERM)) /* Print error only when pstore.backend == nvram */ diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c index a5e1d963208e7..9953e50667ec1 100644 --- a/drivers/acpi/apei/erst.c +++ b/drivers/acpi/apei/erst.c @@ -1176,7 +1176,6 @@ static int __init erst_init(void) "Error Record Serialization Table (ERST) support is initialized.\n"); buf = kmalloc(erst_erange.size, GFP_KERNEL); - spin_lock_init(&erst_info.buf_lock); if (buf) { erst_info.buf = buf + sizeof(struct cper_pstore_record); erst_info.bufsize = erst_erange.size - diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c index cfe87b465819f..0f7d97917197d 100644 --- a/drivers/firmware/efi/efi-pstore.c +++ b/drivers/firmware/efi/efi-pstore.c @@ -259,8 +259,7 @@ static int efi_pstore_write(struct pstore_record *record) efi_name[i] = name[i]; ret = efivar_entry_set_safe(efi_name, vendor, PSTORE_EFI_ATTRIBUTES, - !pstore_cannot_block_path(record->reason), - record->size, record->psi->buf); + preemptible(), record->size, record->psi->buf); if (record->reason == KMSG_DUMP_OOPS) efivar_run_worker(); @@ -369,7 +368,6 @@ static __init int efivars_pstore_init(void) return -ENOMEM; efi_pstore_info.bufsize = 1024; - spin_lock_init(&efi_pstore_info.buf_lock); if (pstore_register(&efi_pstore_info)) { kfree(efi_pstore_info.buf); diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 2387cb74f7299..2d1066ed3c28e 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -161,26 +161,27 @@ 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); #if IS_ENABLED(CONFIG_PSTORE_DEFLATE_COMPRESS) static int zbufsize_deflate(size_t size) @@ -400,23 +401,23 @@ 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; @@ -433,7 +434,7 @@ 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 { @@ -451,7 +452,7 @@ 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); @@ -474,8 +475,8 @@ 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 = { @@ -594,6 +595,7 @@ 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)) { diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 202eaa82bcc63..e6d9560ea4557 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -815,7 +815,6 @@ static int ramoops_probe(struct platform_device *pdev) err = -ENOMEM; goto fail_clear; } - spin_lock_init(&cxt->pstore.buf_lock); cxt->pstore.flags = PSTORE_FLAGS_DMESG; if (cxt->console_size) diff --git a/include/linux/pstore.h b/include/linux/pstore.h index a9ec285d85d1c..b146181e8709f 100644 --- a/include/linux/pstore.h +++ b/include/linux/pstore.h @@ -26,7 +26,7 @@ #include #include #include -#include +#include #include #include @@ -99,7 +99,7 @@ struct pstore_record { * @owner: module which is responsible for this backend driver * @name: name of the backend driver * - * @buf_lock: spinlock to serialize access to @buf + * @buf_lock: semaphore to serialize access to @buf * @buf: preallocated crash dump buffer * @bufsize: size of @buf available for crash dump bytes (must match * smallest number of bytes available for writing to a @@ -184,7 +184,7 @@ struct pstore_info { struct module *owner; char *name; - spinlock_t buf_lock; + struct semaphore buf_lock; char *buf; size_t bufsize; @@ -210,7 +210,6 @@ struct pstore_info { extern int pstore_register(struct pstore_info *); extern void pstore_unregister(struct pstore_info *); -extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason); struct pstore_ftrace_record { unsigned long ip;