From 0b09e711189952ff9d411593a8d74ec12a956c57 Mon Sep 17 00:00:00 2001 From: Uma Krishnan Date: Wed, 21 Jun 2017 21:14:17 -0500 Subject: [PATCH] scsi: cxlflash: Schedule asynchronous reset of the host A context reset failure indicates the AFU is in a bad state. At present, when such a situation occurs, no further action is taken. This leaves the adapter in an unusable state with no recoverable actions. To avoid this situation, context reset failures will be escalated to a host reset operation. This will be done asynchronously to allow the acting thread to return to the user with a failure. Signed-off-by: Uma Krishnan Acked-by: Matthew R. Ochs Signed-off-by: Martin K. Petersen --- drivers/scsi/cxlflash/common.h | 2 + drivers/scsi/cxlflash/main.c | 137 ++++++++++++++++++++++++++++++----------- 2 files changed, 104 insertions(+), 35 deletions(-) diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h index 75decf6..e9b6108 100644 --- a/drivers/scsi/cxlflash/common.h +++ b/drivers/scsi/cxlflash/common.h @@ -15,6 +15,7 @@ #ifndef _CXLFLASH_COMMON_H #define _CXLFLASH_COMMON_H +#include #include #include #include @@ -144,6 +145,7 @@ struct cxlflash_cfg { bool tmf_active; wait_queue_head_t reset_waitq; enum cxlflash_state state; + async_cookie_t async_reset_cookie; }; struct afu_cmd { diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c index b8dc379..20c2c5e 100644 --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -586,6 +586,20 @@ static void free_mem(struct cxlflash_cfg *cfg) } /** + * cxlflash_reset_sync() - synchronizing point for asynchronous resets + * @cfg: Internal structure associated with the host. + */ +static void cxlflash_reset_sync(struct cxlflash_cfg *cfg) +{ + if (cfg->async_reset_cookie == 0) + return; + + /* Wait until all async calls prior to this cookie have completed */ + async_synchronize_cookie(cfg->async_reset_cookie + 1); + cfg->async_reset_cookie = 0; +} + +/** * stop_afu() - stops the AFU command timers and unmaps the MMIO space * @cfg: Internal structure associated with the host. * @@ -601,6 +615,8 @@ static void stop_afu(struct cxlflash_cfg *cfg) int i; cancel_work_sync(&cfg->work_q); + if (!current_is_async()) + cxlflash_reset_sync(cfg); if (likely(afu)) { while (atomic_read(&afu->cmds_active)) @@ -2005,6 +2021,91 @@ err1: } /** + * afu_reset() - resets the AFU + * @cfg: Internal structure associated with the host. + * + * Return: 0 on success, -errno on failure + */ +static int afu_reset(struct cxlflash_cfg *cfg) +{ + struct device *dev = &cfg->dev->dev; + int rc = 0; + + /* Stop the context before the reset. Since the context is + * no longer available restart it after the reset is complete + */ + term_afu(cfg); + + rc = init_afu(cfg); + + dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc); + return rc; +} + +/** + * drain_ioctls() - wait until all currently executing ioctls have completed + * @cfg: Internal structure associated with the host. + * + * Obtain write access to read/write semaphore that wraps ioctl + * handling to 'drain' ioctls currently executing. + */ +static void drain_ioctls(struct cxlflash_cfg *cfg) +{ + down_write(&cfg->ioctl_rwsem); + up_write(&cfg->ioctl_rwsem); +} + +/** + * cxlflash_async_reset_host() - asynchronous host reset handler + * @data: Private data provided while scheduling reset. + * @cookie: Cookie that can be used for checkpointing. + */ +static void cxlflash_async_reset_host(void *data, async_cookie_t cookie) +{ + struct cxlflash_cfg *cfg = data; + struct device *dev = &cfg->dev->dev; + int rc = 0; + + if (cfg->state != STATE_RESET) { + dev_dbg(dev, "%s: Not performing a reset, state=%d\n", + __func__, cfg->state); + goto out; + } + + drain_ioctls(cfg); + cxlflash_mark_contexts_error(cfg); + rc = afu_reset(cfg); + if (rc) + cfg->state = STATE_FAILTERM; + else + cfg->state = STATE_NORMAL; + wake_up_all(&cfg->reset_waitq); + +out: + scsi_unblock_requests(cfg->host); +} + +/** + * cxlflash_schedule_async_reset() - schedule an asynchronous host reset + * @cfg: Internal structure associated with the host. + */ +static void cxlflash_schedule_async_reset(struct cxlflash_cfg *cfg) +{ + struct device *dev = &cfg->dev->dev; + + if (cfg->state != STATE_NORMAL) { + dev_dbg(dev, "%s: Not performing reset state=%d\n", + __func__, cfg->state); + return; + } + + cfg->state = STATE_RESET; + scsi_block_requests(cfg->host); + cfg->async_reset_cookie = async_schedule(cxlflash_async_reset_host, + cfg); +} + +/** * cxlflash_afu_sync() - builds and sends an AFU sync command * @afu: AFU associated with the host. * @ctx_hndl_u: Identifies context requesting sync. @@ -2085,6 +2186,7 @@ retry: rc = afu->context_reset(hwq); if (!rc && ++nretry < 2) goto retry; + cxlflash_schedule_async_reset(cfg); } out: @@ -2096,41 +2198,6 @@ out: } /** - * afu_reset() - resets the AFU - * @cfg: Internal structure associated with the host. - * - * Return: 0 on success, -errno on failure - */ -static int afu_reset(struct cxlflash_cfg *cfg) -{ - struct device *dev = &cfg->dev->dev; - int rc = 0; - - /* Stop the context before the reset. Since the context is - * no longer available restart it after the reset is complete - */ - term_afu(cfg); - - rc = init_afu(cfg); - - dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc); - return rc; -} - -/** - * drain_ioctls() - wait until all currently executing ioctls have completed - * @cfg: Internal structure associated with the host. - * - * Obtain write access to read/write semaphore that wraps ioctl - * handling to 'drain' ioctls currently executing. - */ -static void drain_ioctls(struct cxlflash_cfg *cfg) -{ - down_write(&cfg->ioctl_rwsem); - up_write(&cfg->ioctl_rwsem); -} - -/** * cxlflash_eh_device_reset_handler() - reset a single LUN * @scp: SCSI command to send. * -- 2.7.4