From: Stanley Chu stanley.chu@mediatek.com
[ Upstream commit 0fef6bb730c490fcdc4347dbd21646d3ffe62cf5 ]
In MCQ mode, when a device command uses a hardware queue shared with other commands, a race condition may occur in the following scenario:
1. A device command is completed in CQx with CQE entry "e".
2. The interrupt handler copies the "cqe" pointer to "hba->dev_cmd.cqe" and completes "hba->dev_cmd.complete".
3. The "ufshcd_wait_for_dev_cmd()" function is awakened and retrieves the OCS value from "hba->dev_cmd.cqe".
However, there is a possibility that the CQE entry "e" will be overwritten by newly completed commands in CQx, resulting in an incorrect OCS value being received by "ufshcd_wait_for_dev_cmd()".
To avoid this race condition, the OCS value should be immediately copied to the struct "lrb" of the device command. Then "ufshcd_wait_for_dev_cmd()" can retrieve the OCS value from the struct "lrb".
Fixes: 57b1c0ef89ac ("scsi: ufs: core: mcq: Add support to allocate multiple queues") Suggested-by: Can Guo quic_cang@quicinc.com Signed-off-by: Stanley Chu stanley.chu@mediatek.com Link: https://lore.kernel.org/r/20230610021553.1213-2-powen.kao@mediatek.com Tested-by: Po-Wen Kao powen.kao@mediatek.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/ufs/core/ufshcd.c | 10 +++++++--- include/ufs/ufshcd.h | 1 - 2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 41f383b588865..6d8ef80d9cbc4 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -3097,7 +3097,7 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba, * not trigger any race conditions. */ hba->dev_cmd.complete = NULL; - err = ufshcd_get_tr_ocs(lrbp, hba->dev_cmd.cqe); + err = ufshcd_get_tr_ocs(lrbp, NULL); if (!err) err = ufshcd_dev_cmd_completion(hba, lrbp); } else { @@ -3184,7 +3184,6 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, goto out;
hba->dev_cmd.complete = &wait; - hba->dev_cmd.cqe = NULL;
ufshcd_add_query_upiu_trace(hba, UFS_QUERY_SEND, lrbp->ucd_req_ptr);
@@ -5435,6 +5434,7 @@ void ufshcd_compl_one_cqe(struct ufs_hba *hba, int task_tag, { struct ufshcd_lrb *lrbp; struct scsi_cmnd *cmd; + enum utp_ocs ocs;
lrbp = &hba->lrb[task_tag]; lrbp->compl_time_stamp = ktime_get(); @@ -5450,7 +5450,11 @@ void ufshcd_compl_one_cqe(struct ufs_hba *hba, int task_tag, } else if (lrbp->command_type == UTP_CMD_TYPE_DEV_MANAGE || lrbp->command_type == UTP_CMD_TYPE_UFS_STORAGE) { if (hba->dev_cmd.complete) { - hba->dev_cmd.cqe = cqe; + if (cqe) { + ocs = le32_to_cpu(cqe->status) & MASK_OCS; + lrbp->utr_descriptor_ptr->header.dword_2 = + cpu_to_le32(ocs); + } complete(hba->dev_cmd.complete); ufshcd_clk_scaling_update_busy(hba); } diff --git a/include/ufs/ufshcd.h b/include/ufs/ufshcd.h index df1d04f7a5424..8eecbb3766158 100644 --- a/include/ufs/ufshcd.h +++ b/include/ufs/ufshcd.h @@ -225,7 +225,6 @@ struct ufs_dev_cmd { struct mutex lock; struct completion *complete; struct ufs_query query; - struct cq_entry *cqe; };
/**