Commit 5616b0a4 authored by Martin K. Petersen's avatar Martin K. Petersen Committed by James Bottomley

[SCSI] use the scsi data buffer length to extract transfer size

Commit 8846bab1 introduced a helper that can be used to query the
wire transfer size for a SCSI command taking protection information into

However, some commands do not have a 1:1 mapping between the block range
they work on and the payload size (discard, write same). After the
scatterlist has been set up these requests use __data_len to store the
number of bytes to report completion on. This means that callers of
scsi_transfer_length() would get the wrong byte count for these types of

To overcome this we make scsi_transfer_length() use the scatterlist
length in the scsi_data_buffer as basis for the wire transfer
calculation instead of __data_len.
Reported-by: default avatarChristoph Hellwig <>
Debugged-by: default avatarMike Christie <>
Signed-off-by: default avatarMartin K. Petersen <>
Signed-off-by: default avatarChristoph Hellwig <>
Reviewed-by: default avatarSagi Grimberg <>
Fixes: d77e6535
Signed-off-by: default avatarJames Bottomley <>
parent a33c070b
......@@ -318,7 +318,7 @@ static inline void set_driver_byte(struct scsi_cmnd *cmd, char status)
static inline unsigned scsi_transfer_length(struct scsi_cmnd *scmd)
unsigned int xfer_len = blk_rq_bytes(scmd->request);
unsigned int xfer_len = scsi_out(scmd)->length;
unsigned int prot_op = scsi_get_prot_op(scmd);
unsigned int sector_size = scmd->device->sector_size;
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