scsi_debug: simple short transfer injection

Add an option to only transfer half the data for every n-th command.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index f3e9cc038d1d9126dadddb686b356b43c43ba1c5..1328a2621070948980d6978fd0eb088b6ec11bbe 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -130,6 +130,7 @@ static const char * scsi_debug_version_date = "20100324";
 #define SCSI_DEBUG_OPT_DIF_ERR   32
 #define SCSI_DEBUG_OPT_DIX_ERR   64
 #define SCSI_DEBUG_OPT_MAC_TIMEOUT  128
+#define SCSI_DEBUG_OPT_SHORT_TRANSFER  256
 /* When "every_nth" > 0 then modulo "every_nth" commands:
  *   - a no response is simulated if SCSI_DEBUG_OPT_TIMEOUT is set
  *   - a RECOVERED_ERROR is simulated on successful read and write
@@ -3583,6 +3584,7 @@ int scsi_debug_queuecommand_lck(struct scsi_cmnd *SCpnt, done_funct_t done)
        int inj_transport = 0;
        int inj_dif = 0;
        int inj_dix = 0;
+       int inj_short = 0;
        int delay_override = 0;
        int unmap = 0;
 
@@ -3628,6 +3630,8 @@ int scsi_debug_queuecommand_lck(struct scsi_cmnd *SCpnt, done_funct_t done)
                        inj_dif = 1; /* to reads and writes below */
                else if (SCSI_DEBUG_OPT_DIX_ERR & scsi_debug_opts)
                        inj_dix = 1; /* to reads and writes below */
+               else if (SCSI_DEBUG_OPT_SHORT_TRANSFER & scsi_debug_opts)
+                       inj_short = 1;
        }
 
        if (devip->wlun) {
@@ -3744,6 +3748,10 @@ read:
                if (scsi_debug_fake_rw)
                        break;
                get_data_transfer_info(cmd, &lba, &num, &ei_lba);
+
+               if (inj_short)
+                       num /= 2;
+
                errsts = resp_read(SCpnt, lba, num, devip, ei_lba);
                if (inj_recovered && (0 == errsts)) {
                        mk_sense_buffer(devip, RECOVERED_ERROR,