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 <ukrishn@xxxxxxxxxxxxxxxxxx>
---
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 <linux/async.h>
#include <linux/irq_poll.h>
#include <linux/list.h>
#include <linux/rwsem.h>
@@ -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 @@ static int init_afu(struct cxlflash_cfg *cfg)
}
/**
+ * 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 @@ int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t ctx_hndl_u,
rc = afu->context_reset(hwq);
if (!rc && ++nretry < 2)
goto retry;
+ cxlflash_schedule_async_reset(cfg);
}
out:
@@ -2096,41 +2198,6 @@ int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t ctx_hndl_u,
}
/**
- * 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.
*
--
2.1.0
