From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751282AbcGNCxE (ORCPT ); Wed, 13 Jul 2016 22:53:04 -0400 Received: from mga04.intel.com ([192.55.52.120]:58335 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751204AbcGNCwp (ORCPT ); Wed, 13 Jul 2016 22:52:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,360,1464678000"; d="scan'208";a="845912774" From: Lv Zheng To: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Len Brown Cc: Lv Zheng , Lv Zheng , , linux-acpi@vger.kernel.org Subject: [PATCH 2/3] ACPI / debugger: Add kernel flushing support Date: Thu, 14 Jul 2016 10:52:37 +0800 Message-Id: <71c8414d9520dcdf460a6559ff312a1da839af79.1468464391.git.lv.zheng@intel.com> X-Mailer: git-send-email 1.7.10 In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch adds debugger log flushing support in kernel via .fsync() callback. The in-kernel flushing is more efficient, because it reduces useless log IOs by bypassing log user_read/kern_write during the flush period. Signed-off-by: Lv Zheng --- drivers/acpi/acpi_dbg.c | 94 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/acpi_dbg.c b/drivers/acpi/acpi_dbg.c index dee8692..90d6922 100644 --- a/drivers/acpi/acpi_dbg.c +++ b/drivers/acpi/acpi_dbg.c @@ -46,6 +46,8 @@ #define ACPI_AML_KERN (ACPI_AML_IN_KERN | ACPI_AML_OUT_KERN) #define ACPI_AML_BUSY (ACPI_AML_USER | ACPI_AML_KERN) #define ACPI_AML_OPEN (ACPI_AML_OPENED | ACPI_AML_CLOSED) +#define ACPI_AML_FLUSHING_LOG 0x0040 /* flushing log output */ +#define ACPI_AML_WAITING_CMD 0x0080 /* waiting for cmd input */ struct acpi_aml_io { wait_queue_head_t wait; @@ -120,6 +122,20 @@ static inline bool __acpi_aml_busy(void) return false; } +static inline bool __acpi_aml_waiting_cmd(void) +{ + if (acpi_aml_io.flags & ACPI_AML_WAITING_CMD) + return true; + return false; +} + +static inline bool __acpi_aml_flushing_log(void) +{ + if (acpi_aml_io.flags & ACPI_AML_FLUSHING_LOG) + return true; + return false; +} + static inline bool __acpi_aml_opened(void) { if (acpi_aml_io.flags & ACPI_AML_OPEN) @@ -152,6 +168,26 @@ static bool acpi_aml_busy(void) return ret; } +static inline bool acpi_aml_waiting_cmd(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = __acpi_aml_waiting_cmd(); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static inline bool acpi_aml_flushing_log(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = __acpi_aml_flushing_log(); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + static bool acpi_aml_used(void) { bool ret; @@ -183,7 +219,8 @@ static bool acpi_aml_kern_writable(void) mutex_lock(&acpi_aml_io.lock); ret = !__acpi_aml_access_ok(ACPI_AML_OUT_KERN) || - __acpi_aml_writable(&acpi_aml_io.out_crc, ACPI_AML_OUT_KERN); + __acpi_aml_writable(&acpi_aml_io.out_crc, ACPI_AML_OUT_KERN) || + __acpi_aml_flushing_log(); mutex_unlock(&acpi_aml_io.lock); return ret; } @@ -264,6 +301,9 @@ static int acpi_aml_write_kern(const char *buf, int len) int n; char *p; + if (acpi_aml_flushing_log()) + return len; + ret = acpi_aml_lock_write(crc, ACPI_AML_OUT_KERN); if (ret < 0) return ret; @@ -458,9 +498,18 @@ static int acpi_aml_wait_command_ready(bool single_step, else acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT); + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags |= ACPI_AML_WAITING_CMD; + wake_up_interruptible(&acpi_aml_io.wait); + mutex_unlock(&acpi_aml_io.lock); + status = acpi_os_get_line(buffer, length, NULL); if (ACPI_FAILURE(status)) return -EINVAL; + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags &= ~ACPI_AML_WAITING_CMD; + mutex_unlock(&acpi_aml_io.lock); return 0; } @@ -593,9 +642,11 @@ static int acpi_aml_read_user(char __user *buf, int len) smp_rmb(); p = &crc->buf[crc->tail]; n = min(len, circ_count_to_end(crc)); - if (copy_to_user(buf, p, n)) { - ret = -EFAULT; - goto out; + if (!acpi_aml_flushing_log()) { + if (copy_to_user(buf, p, n)) { + ret = -EFAULT; + goto out; + } } /* sync tail after removing logs */ smp_mb(); @@ -731,10 +782,45 @@ static unsigned int acpi_aml_poll(struct file *file, poll_table *wait) return masks; } +static int acpi_aml_flush(void) +{ + int ret; + + /* + * Discard output buffer and put the driver into a state waiting + * for the new user input. + */ + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags |= ACPI_AML_FLUSHING_LOG; + mutex_unlock(&acpi_aml_io.lock); + + ret = wait_event_interruptible(acpi_aml_io.wait, + acpi_aml_waiting_cmd()); + (void)acpi_aml_read_user(NULL, ACPI_AML_BUF_SIZE); + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags &= ~ACPI_AML_FLUSHING_LOG; + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static int acpi_aml_fsync(struct file *file, + loff_t start, loff_t end, int datasync) +{ + struct inode *inode = file_inode(file); + int ret; + + inode_lock(inode); + ret = acpi_aml_flush(); + inode_unlock(inode); + return ret; +} + static const struct file_operations acpi_aml_operations = { .read = acpi_aml_read, .write = acpi_aml_write, .poll = acpi_aml_poll, + .fsync = acpi_aml_fsync, .open = acpi_aml_open, .release = acpi_aml_release, .llseek = generic_file_llseek, -- 1.7.10