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-dbg.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'drivers/acpi/apei/erst-dbg.c') diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c index de73caf3cebc..a4cfb64c86a1 100644 --- a/drivers/acpi/apei/erst-dbg.c +++ b/drivers/acpi/apei/erst-dbg.c @@ -43,12 +43,27 @@ static DEFINE_MUTEX(erst_dbg_mutex); static int erst_dbg_open(struct inode *inode, struct file *file) { + int rc, *pos; + if (erst_disable) return -ENODEV; + pos = (int *)&file->private_data; + + rc = erst_get_record_id_begin(pos); + if (rc) + return rc; + return nonseekable_open(inode, file); } +static int erst_dbg_release(struct inode *inode, struct file *file) +{ + erst_get_record_id_end(); + + return 0; +} + static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg) { int rc; @@ -79,18 +94,20 @@ static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg) static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf, size_t usize, loff_t *off) { - int rc; + int rc, *pos; ssize_t len = 0; u64 id; - if (*off != 0) + if (*off) return -EINVAL; if (mutex_lock_interruptible(&erst_dbg_mutex) != 0) return -EINTR; + pos = (int *)&filp->private_data; + retry_next: - rc = erst_get_next_record_id(&id); + rc = erst_get_record_id_next(pos, &id); if (rc) goto out; /* no more record */ @@ -181,6 +198,7 @@ out: static const struct file_operations erst_dbg_ops = { .owner = THIS_MODULE, .open = erst_dbg_open, + .release = erst_dbg_release, .read = erst_dbg_read, .write = erst_dbg_write, .unlocked_ioctl = erst_dbg_ioctl, -- cgit v1.2.1