From d28d17a845600dd9f7de241de9b1528a1b138716 Mon Sep 17 00:00:00 2001 From: John Garry Date: Fri, 18 Oct 2024 10:16:55 +0000 Subject: [PATCH] scsi: scsi_debug: Fix do_device_access() handling of unexpected SG copy length If the sg_copy_buffer() call returns less than sdebug_sector_size, then we drop out of the copy loop. However, we still report that we copied the full expected amount, which is not proper. Fix by keeping a running total and return that value. Fixes: 84f3a3c01d70 ("scsi: scsi_debug: Atomic write support") Reported-by: Colin Ian King Suggested-by: Dan Carpenter Signed-off-by: John Garry Link: https://lore.kernel.org/r/20241018101655.4207-1-john.g.garry@oracle.com Reviewed-by: Dan Carpenter Reviewed-by: Colin Ian King Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi_debug.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index d95f417e24c0..9be2a6a00530 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -3651,7 +3651,7 @@ static int do_device_access(struct sdeb_store_info *sip, struct scsi_cmnd *scp, enum dma_data_direction dir; struct scsi_data_buffer *sdb = &scp->sdb; u8 *fsp; - int i; + int i, total = 0; /* * Even though reads are inherently atomic (in this driver), we expect @@ -3688,18 +3688,16 @@ static int do_device_access(struct sdeb_store_info *sip, struct scsi_cmnd *scp, fsp + (block * sdebug_sector_size), sdebug_sector_size, sg_skip, do_write); sdeb_data_sector_unlock(sip, do_write); - if (ret != sdebug_sector_size) { - ret += (i * sdebug_sector_size); + total += ret; + if (ret != sdebug_sector_size) break; - } sg_skip += sdebug_sector_size; if (++block >= sdebug_store_sectors) block = 0; } - ret = num * sdebug_sector_size; sdeb_data_unlock(sip, atomic); - return ret; + return total; } /* Returns number of bytes copied or -1 if error. */