From 885b976fada5bc6595a9fd3e67e3cb1a3d11f50b Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 21 Feb 2011 13:54:41 +0800 Subject: ACPI, APEI, Add ERST record ID cache APEI ERST firmware interface and implementation has no multiple users in mind. For example, if there is four records in storage with ID: 1, 2, 3 and 4, if two ERST readers enumerate the records via GET_NEXT_RECORD_ID as follow, reader 1 reader 2 1 2 3 4 -1 -1 where -1 signals there is no more record ID. Reader 1 has no chance to check record 2 and 4, while reader 2 has no chance to check record 1 and 3. And any other GET_NEXT_RECORD_ID will return -1, that is, other readers will has no chance to check any record even they are not cleared by anyone. This makes raw GET_NEXT_RECORD_ID not suitable for used by multiple users. To solve the issue, an in-memory ERST record ID cache is designed and implemented. When enumerating record ID, the ID returned by GET_NEXT_RECORD_ID is added into cache in addition to be returned to caller. So other readers can check the cache to get all record ID available. Signed-off-by: Huang Ying Reviewed-by: Andi Kleen Signed-off-by: Len Brown --- drivers/acpi/apei/erst.c | 235 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 191 insertions(+), 44 deletions(-) (limited to 'drivers/acpi/apei/erst.c') diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c index cf6db6b7662a..8ff8c32fef58 100644 --- a/drivers/acpi/apei/erst.c +++ b/drivers/acpi/apei/erst.c @@ -429,6 +429,22 @@ ssize_t erst_get_record_count(void) } EXPORT_SYMBOL_GPL(erst_get_record_count); +#define ERST_RECORD_ID_CACHE_SIZE_MIN 16 +#define ERST_RECORD_ID_CACHE_SIZE_MAX 1024 + +struct erst_record_id_cache { + struct mutex lock; + u64 *entries; + int len; + int size; + int refcount; +}; + +static struct erst_record_id_cache erst_record_id_cache = { + .lock = __MUTEX_INITIALIZER(erst_record_id_cache.lock), + .refcount = 0, +}; + static int __erst_get_next_record_id(u64 *record_id) { struct apei_exec_context ctx; @@ -443,26 +459,179 @@ static int __erst_get_next_record_id(u64 *record_id) return 0; } +int erst_get_record_id_begin(int *pos) +{ + int rc; + + if (erst_disable) + return -ENODEV; + + rc = mutex_lock_interruptible(&erst_record_id_cache.lock); + if (rc) + return rc; + erst_record_id_cache.refcount++; + mutex_unlock(&erst_record_id_cache.lock); + + *pos = 0; + + return 0; +} +EXPORT_SYMBOL_GPL(erst_get_record_id_begin); + +/* erst_record_id_cache.lock must be held by caller */ +static int __erst_record_id_cache_add_one(void) +{ + u64 id, prev_id, first_id; + int i, rc; + u64 *entries; + unsigned long flags; + + id = prev_id = first_id = APEI_ERST_INVALID_RECORD_ID; +retry: + raw_spin_lock_irqsave(&erst_lock, flags); + rc = __erst_get_next_record_id(&id); + raw_spin_unlock_irqrestore(&erst_lock, flags); + if (rc == -ENOENT) + return 0; + if (rc) + return rc; + if (id == APEI_ERST_INVALID_RECORD_ID) + return 0; + /* can not skip current ID, or loop back to first ID */ + if (id == prev_id || id == first_id) + return 0; + if (first_id == APEI_ERST_INVALID_RECORD_ID) + first_id = id; + prev_id = id; + + entries = erst_record_id_cache.entries; + for (i = 0; i < erst_record_id_cache.len; i++) { + if (entries[i] == id) + break; + } + /* record id already in cache, try next */ + if (i < erst_record_id_cache.len) + goto retry; + if (erst_record_id_cache.len >= erst_record_id_cache.size) { + int new_size, alloc_size; + u64 *new_entries; + + new_size = erst_record_id_cache.size * 2; + new_size = clamp_val(new_size, ERST_RECORD_ID_CACHE_SIZE_MIN, + ERST_RECORD_ID_CACHE_SIZE_MAX); + if (new_size <= erst_record_id_cache.size) { + if (printk_ratelimit()) + pr_warning(FW_WARN ERST_PFX + "too many record ID!\n"); + return 0; + } + alloc_size = new_size * sizeof(entries[0]); + if (alloc_size < PAGE_SIZE) + new_entries = kmalloc(alloc_size, GFP_KERNEL); + else + new_entries = vmalloc(alloc_size); + if (!new_entries) + return -ENOMEM; + memcpy(new_entries, entries, + erst_record_id_cache.len * sizeof(entries[0])); + if (erst_record_id_cache.size < PAGE_SIZE) + kfree(entries); + else + vfree(entries); + erst_record_id_cache.entries = entries = new_entries; + erst_record_id_cache.size = new_size; + } + entries[i] = id; + erst_record_id_cache.len++; + + return 1; +} + /* * Get the record ID of an existing error record on the persistent * storage. If there is no error record on the persistent storage, the * returned record_id is APEI_ERST_INVALID_RECORD_ID. */ -int erst_get_next_record_id(u64 *record_id) +int erst_get_record_id_next(int *pos, u64 *record_id) { - int rc; - unsigned long flags; + int rc = 0; + u64 *entries; if (erst_disable) return -ENODEV; - raw_spin_lock_irqsave(&erst_lock, flags); - rc = __erst_get_next_record_id(record_id); - raw_spin_unlock_irqrestore(&erst_lock, flags); + /* must be enclosed by erst_get_record_id_begin/end */ + BUG_ON(!erst_record_id_cache.refcount); + BUG_ON(*pos < 0 || *pos > erst_record_id_cache.len); + + mutex_lock(&erst_record_id_cache.lock); + entries = erst_record_id_cache.entries; + for (; *pos < erst_record_id_cache.len; (*pos)++) + if (entries[*pos] != APEI_ERST_INVALID_RECORD_ID) + break; + /* found next record id in cache */ + if (*pos < erst_record_id_cache.len) { + *record_id = entries[*pos]; + (*pos)++; + goto out_unlock; + } + + /* Try to add one more record ID to cache */ + rc = __erst_record_id_cache_add_one(); + if (rc < 0) + goto out_unlock; + /* successfully add one new ID */ + if (rc == 1) { + *record_id = erst_record_id_cache.entries[*pos]; + (*pos)++; + rc = 0; + } else { + *pos = -1; + *record_id = APEI_ERST_INVALID_RECORD_ID; + } +out_unlock: + mutex_unlock(&erst_record_id_cache.lock); return rc; } -EXPORT_SYMBOL_GPL(erst_get_next_record_id); +EXPORT_SYMBOL_GPL(erst_get_record_id_next); + +/* erst_record_id_cache.lock must be held by caller */ +static void __erst_record_id_cache_compact(void) +{ + int i, wpos = 0; + u64 *entries; + + if (erst_record_id_cache.refcount) + return; + + entries = erst_record_id_cache.entries; + for (i = 0; i < erst_record_id_cache.len; i++) { + if (entries[i] == APEI_ERST_INVALID_RECORD_ID) + continue; + if (wpos != i) + memcpy(&entries[wpos], &entries[i], sizeof(entries[i])); + wpos++; + } + erst_record_id_cache.len = wpos; +} + +void erst_get_record_id_end(void) +{ + /* + * erst_disable != 0 should be detected by invoker via the + * return value of erst_get_record_id_begin/next, so this + * function should not be called for erst_disable != 0. + */ + BUG_ON(erst_disable); + + mutex_lock(&erst_record_id_cache.lock); + erst_record_id_cache.refcount--; + BUG_ON(erst_record_id_cache.refcount < 0); + __erst_record_id_cache_compact(); + mutex_unlock(&erst_record_id_cache.lock); +} +EXPORT_SYMBOL_GPL(erst_get_record_id_end); static int __erst_write_to_storage(u64 offset) { @@ -703,56 +872,34 @@ ssize_t erst_read(u64 record_id, struct cper_record_header *record, } EXPORT_SYMBOL_GPL(erst_read); -/* - * If return value > buflen, the buffer size is not big enough, - * else if return value = 0, there is no more record to read, - * else if return value < 0, something goes wrong, - * else everything is OK, and return value is record length - */ -ssize_t erst_read_next(struct cper_record_header *record, size_t buflen) -{ - int rc; - ssize_t len; - unsigned long flags; - u64 record_id; - - if (erst_disable) - return -ENODEV; - - raw_spin_lock_irqsave(&erst_lock, flags); - rc = __erst_get_next_record_id(&record_id); - if (rc) { - raw_spin_unlock_irqrestore(&erst_lock, flags); - return rc; - } - /* no more record */ - if (record_id == APEI_ERST_INVALID_RECORD_ID) { - raw_spin_unlock_irqrestore(&erst_lock, flags); - return 0; - } - - len = __erst_read(record_id, record, buflen); - raw_spin_unlock_irqrestore(&erst_lock, flags); - - return len; -} -EXPORT_SYMBOL_GPL(erst_read_next); - int erst_clear(u64 record_id) { - int rc; + int rc, i; unsigned long flags; + u64 *entries; if (erst_disable) return -ENODEV; + rc = mutex_lock_interruptible(&erst_record_id_cache.lock); + if (rc) + return rc; raw_spin_lock_irqsave(&erst_lock, flags); if (erst_erange.attr & ERST_RANGE_NVRAM) rc = __erst_clear_from_nvram(record_id); else rc = __erst_clear_from_storage(record_id); raw_spin_unlock_irqrestore(&erst_lock, flags); - + if (rc) + goto out; + entries = erst_record_id_cache.entries; + for (i = 0; i < erst_record_id_cache.len; i++) { + if (entries[i] == record_id) + entries[i] = APEI_ERST_INVALID_RECORD_ID; + } + __erst_record_id_cache_compact(); +out: + mutex_unlock(&erst_record_id_cache.lock); return rc; } EXPORT_SYMBOL_GPL(erst_clear); -- cgit v1.2.3