@@ -898,6 +898,7 @@ struct ufs_hba {
bool is_urgent_bkops_lvl_checked;
struct rw_semaphore host_rw_sem;
+ struct task_struct *excl_task;
unsigned char desc_size[QUERY_DESC_IDN_MAX];
atomic_t scsi_block_reqs_cnt;
@@ -1420,31 +1421,45 @@ static inline int ufshcd_rpmb_rpm_put(struct ufs_hba *hba)
static inline void ufshcd_down_read(struct ufs_hba *hba)
{
- down_read(&hba->host_rw_sem);
+ if (hba->excl_task != current)
+ down_read(&hba->host_rw_sem);
}
static inline void ufshcd_up_read(struct ufs_hba *hba)
{
- up_read(&hba->host_rw_sem);
+ if (hba->excl_task != current)
+ up_read(&hba->host_rw_sem);
}
static inline int ufshcd_down_read_trylock(struct ufs_hba *hba)
{
+ if (hba->excl_task == current)
+ return 1;
+
return down_read_trylock(&hba->host_rw_sem);
}
static inline void ufshcd_down_write(struct ufs_hba *hba)
{
down_write(&hba->host_rw_sem);
+ /*
+ * Assign exclusive access to this task, which enables bypassing
+ * down_read/up_read, refer ufshcd_down_read() and ufshcd_up_read().
+ * Note, if the same task will not be doing up_write(), it must set
+ * hba->excl_task to NULL itself.
+ */
+ hba->excl_task = current;
}
static inline void ufshcd_up_write(struct ufs_hba *hba)
{
+ hba->excl_task = NULL;
up_write(&hba->host_rw_sem);
}
static inline void ufshcd_downgrade_write(struct ufs_hba *hba)
{
+ hba->excl_task = NULL;
downgrade_write(&hba->host_rw_sem);
}
In preparation 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.h | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)