@@ -2908,18 +2908,14 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
int err;
int tag;
- ufshcd_down_read(hba);
-
/*
* Get free slot, sleep if slots are unavailable.
* Even though we use wait_event() which sleeps indefinitely,
* the maximum wait time is bounded by SCSI request timeout.
*/
req = blk_get_request(q, REQ_OP_DRV_OUT, 0);
- if (IS_ERR(req)) {
- err = PTR_ERR(req);
- goto out_unlock;
- }
+ if (IS_ERR(req))
+ return PTR_ERR(req);
tag = req->tag;
WARN_ONCE(tag < 0, "Invalid tag %d\n", tag);
/* Set the timeout such that the SCSI error handler is not activated. */
@@ -2943,8 +2939,6 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba,
out:
blk_put_request(req);
-out_unlock:
- ufshcd_up_read(hba);
return err;
}
@@ -2995,6 +2989,25 @@ static int ufshcd_query_flag_retry(struct ufs_hba *hba,
return ret;
}
+static void ufshcd_dev_cmd_lock(struct ufs_hba *hba)
+{
+ /* Ungate while not holding other locks */
+ ufshcd_hold(hba, false);
+ ufshcd_down_read(hba);
+ /*
+ * Take the mutex after ufshcd_down_read() to avoid deadlocking against
+ * the owner of ufshcd_down_write().
+ */
+ mutex_lock(&hba->dev_cmd.lock);
+}
+
+static void ufshcd_dev_cmd_unlock(struct ufs_hba *hba)
+{
+ mutex_unlock(&hba->dev_cmd.lock);
+ ufshcd_up_read(hba);
+ ufshcd_release(hba);
+}
+
/**
* ufshcd_query_flag() - API function for sending flag query requests
* @hba: per-adapter instance
@@ -3015,8 +3028,7 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
BUG_ON(!hba);
- ufshcd_hold(hba, false);
- mutex_lock(&hba->dev_cmd.lock);
+ ufshcd_dev_cmd_lock(hba);
ufshcd_init_query(hba, &request, &response, opcode, idn, index,
selector);
@@ -3058,8 +3070,7 @@ int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
MASK_QUERY_UPIU_FLAG_LOC) & 0x1;
out_unlock:
- mutex_unlock(&hba->dev_cmd.lock);
- ufshcd_release(hba);
+ ufshcd_dev_cmd_unlock(hba);
return err;
}
@@ -3089,9 +3100,8 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode,
return -EINVAL;
}
- ufshcd_hold(hba, false);
+ ufshcd_dev_cmd_lock(hba);
- mutex_lock(&hba->dev_cmd.lock);
ufshcd_init_query(hba, &request, &response, opcode, idn, index,
selector);
@@ -3121,8 +3131,7 @@ int ufshcd_query_attr(struct ufs_hba *hba, enum query_opcode opcode,
*attr_val = be32_to_cpu(response->upiu_res.value);
out_unlock:
- mutex_unlock(&hba->dev_cmd.lock);
- ufshcd_release(hba);
+ ufshcd_dev_cmd_unlock(hba);
return err;
}
@@ -3185,9 +3194,8 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba,
return -EINVAL;
}
- ufshcd_hold(hba, false);
+ ufshcd_dev_cmd_lock(hba);
- mutex_lock(&hba->dev_cmd.lock);
ufshcd_init_query(hba, &request, &response, opcode, idn, index,
selector);
hba->dev_cmd.query.descriptor = desc_buf;
@@ -3220,8 +3228,7 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba,
out_unlock:
hba->dev_cmd.query.descriptor = NULL;
- mutex_unlock(&hba->dev_cmd.lock);
- ufshcd_release(hba);
+ ufshcd_dev_cmd_unlock(hba);
return err;
}
@@ -4766,8 +4773,7 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
int err = 0;
int retries;
- ufshcd_hold(hba, false);
- mutex_lock(&hba->dev_cmd.lock);
+ ufshcd_dev_cmd_lock(hba);
for (retries = NOP_OUT_RETRIES; retries > 0; retries--) {
err = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_NOP,
NOP_OUT_TIMEOUT);
@@ -4777,8 +4783,7 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
dev_dbg(hba->dev, "%s: error %d retrying\n", __func__, err);
}
- mutex_unlock(&hba->dev_cmd.lock);
- ufshcd_release(hba);
+ ufshcd_dev_cmd_unlock(hba);
if (err)
dev_err(hba->dev, "%s: NOP OUT failed %d\n", __func__, err);
@@ -6699,13 +6704,9 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba,
int tag;
u8 upiu_flags;
- ufshcd_down_read(hba);
-
req = blk_get_request(q, REQ_OP_DRV_OUT, 0);
- if (IS_ERR(req)) {
- err = PTR_ERR(req);
- goto out_unlock;
- }
+ if (IS_ERR(req))
+ return PTR_ERR(req);
tag = req->tag;
WARN_ONCE(tag < 0, "Invalid tag %d\n", tag);
@@ -6783,8 +6784,6 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba,
out:
blk_put_request(req);
-out_unlock:
- ufshcd_up_read(hba);
return err;
}
@@ -6821,13 +6820,11 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
cmd_type = DEV_CMD_TYPE_NOP;
fallthrough;
case UPIU_TRANSACTION_QUERY_REQ:
- ufshcd_hold(hba, false);
- mutex_lock(&hba->dev_cmd.lock);
+ ufshcd_dev_cmd_lock(hba);
err = ufshcd_issue_devman_upiu_cmd(hba, req_upiu, rsp_upiu,
desc_buff, buff_len,
cmd_type, desc_op);
- mutex_unlock(&hba->dev_cmd.lock);
- ufshcd_release(hba);
+ ufshcd_dev_cmd_unlock(hba);
break;
case UPIU_TRANSACTION_TASK_REQ:
Consolidate the locking for dev_cmd's in one new function ufshcd_dev_cmd_lock() and reorder dev_cmd.lock mutex after ufshcd_down_read() to pave the way to hold ufshcd_down_write() lock for the entire error handler duration. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> --- drivers/scsi/ufs/ufshcd.c | 69 +++++++++++++++++++-------------------- 1 file changed, 33 insertions(+), 36 deletions(-)