On 2/2/23 14:00, Bart Van Assche wrote:
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 <quic_asutoshd@xxxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/scsi_scan.c | 3 +++
include/scsi/scsi_devinfo.h | 4 +++-
2 files changed, 6 insertions(+), 1 deletion(-)
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..783451dfa46e 100644
--- a/include/scsi/scsi_devinfo.h
+++ b/include/scsi/scsi_devinfo.h
@@ -68,8 +68,10 @@
#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
+#define __BLIST_LAST_USED BLIST_BROKEN_FUA
#define __BLIST_HIGH_UNUSED (~(__BLIST_LAST_USED | \
(__force blist_flags_t) \
(replying to an email from two months ago)
I plan to repost the above patch because this patch will allow us to set the
broken_fua flag from user space. Please let me know if there are any objections
or concerns.
Thanks,
Bart.
