UFS devices perform better when using SYNCHRONIZE CACHE command instead of the FUA flag. Introduce the BLIST_BROKEN_FUA flag for using SYNCHRONIZE CACHE instead of FUA. The BLIST_BROKEN_FUA flag can be set by using one of the following approaches: * From user space, by writing into /proc/scsi/device_info. * From the kernel, by setting sdev_bflags from the slave_alloc callback. For a prior version of this patch, see also https://lore.kernel.org/lkml/YpecaXfIxZBHIcfj@xxxxxxxxxx/T/ Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Cc: Asutosh Das <asutoshd@xxxxxxxxxxxxxx> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> --- drivers/scsi/scsi_scan.c | 3 +++ include/scsi/scsi_devinfo.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index a62925355c2c..c1eb6bfe7ed2 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -1020,6 +1020,9 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, if (*bflags & BLIST_NO_RSOC) sdev->no_report_opcodes = 1; + if (*bflags & BLIST_BROKEN_FUA) + sdev->broken_fua = 1; + /* set the device running here so that slave configure * may do I/O */ mutex_lock(&sdev->state_mutex); diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h index 5d14adae21c7..f89e8d1a9d64 100644 --- a/include/scsi/scsi_devinfo.h +++ b/include/scsi/scsi_devinfo.h @@ -68,6 +68,8 @@ #define BLIST_RETRY_ITF ((__force blist_flags_t)(1ULL << 32)) /* Always retry ABORTED_COMMAND with ASC 0xc1 */ #define BLIST_RETRY_ASC_C1 ((__force blist_flags_t)(1ULL << 33)) +/* Use SYNCHRONIZE CACHE instead of FUA */ +#define BLIST_BROKEN_FUA ((__force blist_flags_t)(1ULL << 34)) #define __BLIST_LAST_USED BLIST_RETRY_ASC_C1
