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Message-ID: <20230901094127.2010873-12-haowenchao2@huawei.com>
Date: Fri, 1 Sep 2023 17:41:19 +0800
From: Wenchao Hao <haowenchao2@...wei.com>
To: "James E . J . Bottomley" <jejb@...ux.ibm.com>,
"Martin K . Petersen" <martin.petersen@...cle.com>,
<linux-scsi@...r.kernel.org>
CC: Hannes Reinecke <hare@...e.de>, <linux-kernel@...r.kernel.org>,
<louhongxiang@...wei.com>, <lixiaokeng@...wei.com>,
Wenchao Hao <haowenchao2@...wei.com>
Subject: [RFC PATCH v2 11/19] scsi: scsi_error: Add a general target based error handler
Add a general target based error handler which can be used by drivers
directly. This error handler implements an scsi_target_eh, when handling
error commands, it would call helper function scsi_starget_eh() added
before to try recover error commands.
The behavior if scsi_starget_eh() can not recover all error commands
depends on fallback flag, which is initialized when scsi_target is
allocated. If fallback is set, it would fallback to further error
recover strategy like old host based error handle; else it would
mark this scsi devices of this target offline and flush all error
commands.
To using this error handler, drivers should call scsi_target_setup_eh()
in its target_alloc() to setup it's target based error handler;
call scsi_device_clear_eh() in its target_destroy() to clear this
target based error handler.
Signed-off-by: Wenchao Hao <haowenchao2@...wei.com>
---
drivers/scsi/scsi_error.c | 161 ++++++++++++++++++++++++++++++++++++++
include/scsi/scsi_eh.h | 2 +
2 files changed, 163 insertions(+)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 50cd8104175d..1338742e55b9 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -101,6 +101,19 @@ static inline void shost_clear_eh_done(struct Scsi_Host *shost)
}
}
+static inline void starget_clear_eh_done(struct scsi_target *starget)
+{
+ struct scsi_device *sdev;
+
+ list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
+ if (!sdev->eh)
+ continue;
+ sdev->eh->get_sense_done = 0;
+ sdev->eh->stu_done = 0;
+ sdev->eh->reset_done = 0;
+ }
+}
+
void scsi_eh_wakeup(struct Scsi_Host *shost)
{
lockdep_assert_held(shost->host_lock);
@@ -3058,3 +3071,151 @@ void scsi_device_clear_eh(struct scsi_device *sdev)
sdev->eh = NULL;
}
EXPORT_SYMBOL_GPL(scsi_device_clear_eh);
+
+struct starget_eh {
+ spinlock_t eh_lock;
+ unsigned int eh_num;
+ struct list_head eh_cmd_q;
+ struct scsi_target *starget;
+ struct work_struct eh_handle_work;
+ unsigned int fallback:1;
+};
+
+static void starget_eh_work(struct work_struct *work)
+{
+ struct scsi_cmnd *scmd, *next;
+ unsigned long flags;
+ LIST_HEAD(eh_work_q);
+ LIST_HEAD(eh_done_q);
+ struct starget_eh *stargeteh =
+ container_of(work, struct starget_eh, eh_handle_work);
+ struct scsi_target *starget = stargeteh->starget;
+ struct scsi_target_eh *eh = starget->eh;
+
+ spin_lock_irqsave(&stargeteh->eh_lock, flags);
+ list_splice_init(&stargeteh->eh_cmd_q, &eh_work_q);
+ spin_unlock_irqrestore(&stargeteh->eh_lock, flags);
+
+ if (scsi_starget_eh(starget, &eh_work_q, &eh_done_q))
+ goto out_clear_flag;
+
+ if (!stargeteh->fallback) {
+ scsi_eh_offline_sdevs(&eh_work_q, &eh_done_q);
+ goto out_clear_flag;
+ }
+
+ /*
+ * fallback to host based error handle
+ */
+ SCSI_LOG_ERROR_RECOVERY(2, starget_printk(KERN_INFO, starget,
+ "%s:targeteh fallback to further recovery\n", current->comm));
+ eh->reset_done = 1;
+ list_for_each_entry_safe(scmd, next, &eh_work_q, eh_entry) {
+ list_del_init(&scmd->eh_entry);
+ __scsi_eh_scmd_add(scmd);
+ }
+ goto out_flush_done;
+
+out_clear_flag:
+ starget_clear_eh_done(starget);
+
+out_flush_done:
+ scsi_eh_flush_done_q(&eh_done_q);
+ spin_lock_irqsave(&stargeteh->eh_lock, flags);
+ stargeteh->eh_num = 0;
+ spin_unlock_irqrestore(&stargeteh->eh_lock, flags);
+}
+
+static void starget_eh_add_cmnd(struct scsi_cmnd *scmd)
+{
+ unsigned long flags;
+ struct scsi_target *starget = scmd->device->sdev_target;
+ struct starget_eh *eh;
+
+ eh = (struct starget_eh *)starget->eh->driver_data;
+
+ spin_lock_irqsave(&eh->eh_lock, flags);
+ list_add_tail(&scmd->eh_entry, &eh->eh_cmd_q);
+ eh->eh_num++;
+ spin_unlock_irqrestore(&eh->eh_lock, flags);
+}
+
+static int starget_eh_is_busy(struct scsi_target *starget)
+{
+ int ret = 0;
+ unsigned long flags;
+ struct starget_eh *eh;
+
+ eh = (struct starget_eh *)starget->eh->driver_data;
+
+ spin_lock_irqsave(&eh->eh_lock, flags);
+ ret = eh->eh_num;
+ spin_unlock_irqrestore(&eh->eh_lock, flags);
+
+ return ret;
+}
+
+static int starget_eh_wakeup(struct scsi_target *starget)
+{
+ unsigned long flags;
+ unsigned int nr_error;
+ unsigned int nr_busy;
+ struct starget_eh *eh;
+
+ eh = (struct starget_eh *)starget->eh->driver_data;
+
+ spin_lock_irqsave(&eh->eh_lock, flags);
+ nr_error = eh->eh_num;
+ spin_unlock_irqrestore(&eh->eh_lock, flags);
+
+ nr_busy = atomic_read(&starget->target_busy);
+
+ if (!nr_error || nr_busy != nr_error) {
+ SCSI_LOG_ERROR_RECOVERY(5, starget_printk(KERN_INFO, starget,
+ "%s:targeteh: do not wake up, busy/error is %d/%d\n",
+ current->comm, nr_busy, nr_error));
+ return 0;
+ }
+
+ SCSI_LOG_ERROR_RECOVERY(2, starget_printk(KERN_INFO, starget,
+ "%s:targeteh: waking up, busy/error is %d/%d\n",
+ current->comm, nr_busy, nr_error));
+
+ return schedule_work(&eh->eh_handle_work);
+}
+
+int scsi_target_setup_eh(struct scsi_target *starget, int fallback)
+{
+ struct scsi_target_eh *eh;
+ struct starget_eh *stargeteh;
+
+ eh = kzalloc(sizeof(struct scsi_device_eh) + sizeof(struct starget_eh),
+ GFP_KERNEL);
+ if (!eh) {
+ starget_printk(KERN_ERR, starget, "failed to setup eh\n");
+ return -ENOMEM;
+ }
+ stargeteh = (struct starget_eh *)eh->driver_data;
+
+ eh->add_cmnd = starget_eh_add_cmnd;
+ eh->is_busy = starget_eh_is_busy;
+ eh->wakeup = starget_eh_wakeup;
+ stargeteh->starget = starget;
+ stargeteh->fallback = fallback;
+
+ spin_lock_init(&stargeteh->eh_lock);
+ INIT_LIST_HEAD(&stargeteh->eh_cmd_q);
+ INIT_WORK(&stargeteh->eh_handle_work, starget_eh_work);
+
+ starget->eh = eh;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(scsi_target_setup_eh);
+
+void scsi_target_clear_eh(struct scsi_target *starget)
+{
+ kfree(starget->eh);
+ starget->eh = NULL;
+}
+EXPORT_SYMBOL_GPL(scsi_target_clear_eh);
diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
index 80e2f130e884..011f63030589 100644
--- a/include/scsi/scsi_eh.h
+++ b/include/scsi/scsi_eh.h
@@ -24,6 +24,8 @@ extern int scsi_starget_eh(struct scsi_target *starget,
struct list_head *workq, struct list_head *doneq);
extern int scsi_device_setup_eh(struct scsi_device *sdev, int fallback);
extern void scsi_device_clear_eh(struct scsi_device *sdev);
+extern int scsi_target_setup_eh(struct scsi_target *starget, int fallback);
+extern void scsi_target_clear_eh(struct scsi_target *starget);
static inline bool scsi_sense_is_deferred(const struct scsi_sense_hdr *sshdr)
{
--
2.35.3
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