diff options
Diffstat (limited to 'drivers/scsi/scsi_debug.c')
| -rw-r--r-- | drivers/scsi/scsi_debug.c | 42 |
1 files changed, 39 insertions, 3 deletions
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 4c6c448dc2df..4509087347d3 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -39,6 +39,7 @@ #include <linux/uuid.h> #include <linux/t10-pi.h> #include <linux/msdos_partition.h> +#include <linux/random.h> #include <net/checksum.h> @@ -126,6 +127,7 @@ static const char *sdebug_version_date = "20190125"; #define DEF_PHYSBLK_EXP 0 #define DEF_OPT_XFERLEN_EXP 0 #define DEF_PTYPE TYPE_DISK +#define DEF_RANDOM false #define DEF_REMOVABLE false #define DEF_SCSI_LEVEL 7 /* INQUIRY, byte2 [6->SPC-4; 7->SPC-5] */ #define DEF_SECTOR_SIZE 512 @@ -656,6 +658,7 @@ static unsigned int sdebug_unmap_max_blocks = DEF_UNMAP_MAX_BLOCKS; static unsigned int sdebug_unmap_max_desc = DEF_UNMAP_MAX_DESC; static unsigned int sdebug_write_same_length = DEF_WRITESAME_LENGTH; static int sdebug_uuid_ctl = DEF_UUID_CTL; +static bool sdebug_random = DEF_RANDOM; static bool sdebug_removable = DEF_REMOVABLE; static bool sdebug_clustering; static bool sdebug_host_lock = DEF_HOST_LOCK; @@ -4355,9 +4358,21 @@ static int schedule_resp(struct scsi_cmnd *cmnd, struct sdebug_dev_info *devip, ktime_t kt; if (delta_jiff > 0) { - kt = ns_to_ktime((u64)delta_jiff * (NSEC_PER_SEC / HZ)); - } else - kt = ndelay; + u64 ns = jiffies_to_nsecs(delta_jiff); + + if (sdebug_random && ns < U32_MAX) { + ns = prandom_u32_max((u32)ns); + } else if (sdebug_random) { + ns >>= 12; /* scale to 4 usec precision */ + if (ns < U32_MAX) /* over 4 hours max */ + ns = prandom_u32_max((u32)ns); + ns <<= 12; + } + kt = ns_to_ktime(ns); + } else { /* ndelay has a 4.2 second max */ + kt = sdebug_random ? prandom_u32_max((u32)ndelay) : + (u32)ndelay; + } if (!sd_dp->init_hrt) { sd_dp->init_hrt = true; sqcp->sd_dp = sd_dp; @@ -4452,6 +4467,7 @@ module_param_named(opts, sdebug_opts, int, S_IRUGO | S_IWUSR); module_param_named(physblk_exp, sdebug_physblk_exp, int, S_IRUGO); module_param_named(opt_xferlen_exp, sdebug_opt_xferlen_exp, int, S_IRUGO); module_param_named(ptype, sdebug_ptype, int, S_IRUGO | S_IWUSR); +module_param_named(random, sdebug_random, bool, S_IRUGO | S_IWUSR); module_param_named(removable, sdebug_removable, bool, S_IRUGO | S_IWUSR); module_param_named(scsi_level, sdebug_scsi_level, int, S_IRUGO); module_param_named(sector_size, sdebug_sector_size, int, S_IRUGO); @@ -4512,6 +4528,7 @@ MODULE_PARM_DESC(opts, "1->noise, 2->medium_err, 4->timeout, 8->recovered_err... MODULE_PARM_DESC(physblk_exp, "physical block exponent (def=0)"); MODULE_PARM_DESC(opt_xferlen_exp, "optimal transfer length granularity exponent (def=physblk_exp)"); MODULE_PARM_DESC(ptype, "SCSI peripheral type(def=0[disk])"); +MODULE_PARM_DESC(random, "If set, uniformly randomize command duration between 0 and delay_in_ns"); MODULE_PARM_DESC(removable, "claim to have removable media (def=0)"); MODULE_PARM_DESC(scsi_level, "SCSI level to simulate(def=7[SPC-5])"); MODULE_PARM_DESC(sector_size, "logical block size in bytes (def=512)"); @@ -5102,6 +5119,24 @@ static ssize_t map_show(struct device_driver *ddp, char *buf) } static DRIVER_ATTR_RO(map); +static ssize_t random_show(struct device_driver *ddp, char *buf) +{ + return scnprintf(buf, PAGE_SIZE, "%d\n", sdebug_random); +} + +static ssize_t random_store(struct device_driver *ddp, const char *buf, + size_t count) +{ + bool v; + + if (kstrtobool(buf, &v)) + return -EINVAL; + + sdebug_random = v; + return count; +} +static DRIVER_ATTR_RW(random); + static ssize_t removable_show(struct device_driver *ddp, char *buf) { return scnprintf(buf, PAGE_SIZE, "%d\n", sdebug_removable ? 1 : 0); @@ -5212,6 +5247,7 @@ static struct attribute *sdebug_drv_attrs[] = { &driver_attr_guard.attr, &driver_attr_ato.attr, &driver_attr_map.attr, + &driver_attr_random.attr, &driver_attr_removable.attr, &driver_attr_host_lock.attr, &driver_attr_ndelay.attr, |