This is a note to let you know that I've just added the patch titled
scsi: tracing: Fix handling of TRANSFER LENGTH == 0 for READ(6) and WRITE(6)
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-tracing-fix-handling-of-transfer-length-0-for-r.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6cc4827ebb9adcadb10e3e68e5bdf4e85f9e2eb0
Author: Bart Van Assche <bvanassche@xxxxxxx>
Date: Tue Nov 5 13:55:53 2019 -0800
scsi: tracing: Fix handling of TRANSFER LENGTH == 0 for READ(6) and WRITE(6)
[ Upstream commit f6b8540f40201bff91062dd64db8e29e4ddaaa9d ]
According to SBC-2 a TRANSFER LENGTH field of zero means that 256 logical
blocks must be transferred. Make the SCSI tracing code follow SBC-2.
Fixes: bf8162354233 ("[SCSI] add scsi trace core functions and put trace points")
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191105215553.185018-1-bvanassche@xxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/scsi/scsi_trace.c b/drivers/scsi/scsi_trace.c
index 08bb47b53bc3..551fd0329bca 100644
--- a/drivers/scsi/scsi_trace.c
+++ b/drivers/scsi/scsi_trace.c
@@ -29,15 +29,18 @@ static const char *
scsi_trace_rw6(struct trace_seq *p, unsigned char *cdb, int len)
{
const char *ret = trace_seq_buffer_ptr(p);
- sector_t lba = 0, txlen = 0;
+ u32 lba = 0, txlen;
lba |= ((cdb[1] & 0x1F) << 16);
lba |= (cdb[2] << 8);
lba |= cdb[3];
- txlen = cdb[4];
+ /*
+ * From SBC-2: a TRANSFER LENGTH field set to zero specifies that 256
+ * logical blocks shall be read (READ(6)) or written (WRITE(6)).
+ */
+ txlen = cdb[4] ? cdb[4] : 256;
- trace_seq_printf(p, "lba=%llu txlen=%llu",
- (unsigned long long)lba, (unsigned long long)txlen);
+ trace_seq_printf(p, "lba=%u txlen=%u", lba, txlen);
trace_seq_putc(p, 0);
return ret;
