Commit 7109f370 authored by Douglas Gilbert's avatar Douglas Gilbert Committed by Martin K. Petersen
Browse files

scsi: scsi_debug: Add no_rwlock parameter 

By default, this driver places a read lock around all user data fetches and
a write lock around all user data modifying operations (e.g. WRITE
commands). These locks have "per store" granularity.  Other drivers that
have a similar function (e.g. null_blk) do not take this data integrity
step and run significantly faster in some tests.

In the common case of a (simulated) device to device copy (e.g.  what dd
and its variants do) there should be no need for locks around data
accesses. So add the driver and sysfs parameter no_rwlock which is boolean
and when set does what its name suggests. The default is false for backward
comaptibility.

Link: https://lore.kernel.org/r/20220109012853.301953-7-dgilbert@interlog.com


Signed-off-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 500d0d24

drivers/scsi/scsi_debug.c

+102 −50
Original line number Diff line number Diff line
@@ -787,6 +787,7 @@ static bool sdebug_clustering; 
static bool sdebug_host_lock = DEF_HOST_LOCK;

static bool sdebug_strict = DEF_STRICT;

static bool sdebug_any_injecting_opt;

static bool sdebug_no_rwlock;

static bool sdebug_verbose;

static bool have_dif_prot;

static bool write_since_sync;
@@ -3130,6 +3131,50 @@ static int prot_verify_read(struct scsi_cmnd *scp, sector_t start_sec, 
	return ret;

}



static inline void

sdeb_read_lock(struct sdeb_store_info *sip)

{

	if (sdebug_no_rwlock)

		return;

	if (sip)

		read_lock(&sip->macc_lck);

	else

		read_lock(&sdeb_fake_rw_lck);

}



static inline void

sdeb_read_unlock(struct sdeb_store_info *sip)

{

	if (sdebug_no_rwlock)

		return;

	if (sip)

		read_unlock(&sip->macc_lck);

	else

		read_unlock(&sdeb_fake_rw_lck);

}



static inline void

sdeb_write_lock(struct sdeb_store_info *sip)

{

	if (sdebug_no_rwlock)

		return;

	if (sip)

		write_lock(&sip->macc_lck);

	else

		write_lock(&sdeb_fake_rw_lck);

}



static inline void

sdeb_write_unlock(struct sdeb_store_info *sip)

{

	if (sdebug_no_rwlock)

		return;

	if (sip)

		write_unlock(&sip->macc_lck);

	else

		write_unlock(&sdeb_fake_rw_lck);

}



static int resp_read_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)

{

	bool check_prot;
@@ -3138,7 +3183,6 @@ static int resp_read_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	int ret;

	u64 lba;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;

	u8 *cmd = scp->cmnd;



	switch (cmd[0]) {
@@ -3217,29 +3261,29 @@ static int resp_read_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
		return check_condition_result;

	}



	read_lock(macc_lckp);

	sdeb_read_lock(sip);



	/* DIX + T10 DIF */

	if (unlikely(sdebug_dix && scsi_prot_sg_count(scp))) {

		switch (prot_verify_read(scp, lba, num, ei_lba)) {

		case 1: /* Guard tag error */

			if (cmd[1] >> 5 != 3) { /* RDPROTECT != 3 */

				read_unlock(macc_lckp);

				sdeb_read_unlock(sip);

				mk_sense_buffer(scp, ABORTED_COMMAND, 0x10, 1);

				return check_condition_result;

			} else if (scp->prot_flags & SCSI_PROT_GUARD_CHECK) {

				read_unlock(macc_lckp);

				sdeb_read_unlock(sip);

				mk_sense_buffer(scp, ILLEGAL_REQUEST, 0x10, 1);

				return illegal_condition_result;

			}

			break;

		case 3: /* Reference tag error */

			if (cmd[1] >> 5 != 3) { /* RDPROTECT != 3 */

				read_unlock(macc_lckp);

				sdeb_read_unlock(sip);

				mk_sense_buffer(scp, ABORTED_COMMAND, 0x10, 3);

				return check_condition_result;

			} else if (scp->prot_flags & SCSI_PROT_REF_CHECK) {

				read_unlock(macc_lckp);

				sdeb_read_unlock(sip);

				mk_sense_buffer(scp, ILLEGAL_REQUEST, 0x10, 3);

				return illegal_condition_result;

			}
@@ -3248,7 +3292,7 @@ static int resp_read_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	}



	ret = do_device_access(sip, scp, 0, lba, num, false);

	read_unlock(macc_lckp);

	sdeb_read_unlock(sip);

	if (unlikely(ret == -1))

		return DID_ERROR << 16;
@@ -3436,7 +3480,6 @@ static int resp_write_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	int ret;

	u64 lba;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = &sip->macc_lck;

	u8 *cmd = scp->cmnd;



	switch (cmd[0]) {
@@ -3491,10 +3534,10 @@ static int resp_write_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
				    "to DIF device\n");

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);

	ret = check_device_access_params(scp, lba, num, true);

	if (ret) {

		write_unlock(macc_lckp);

		sdeb_write_unlock(sip);

		return ret;

	}
@@ -3503,22 +3546,22 @@ static int resp_write_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
		switch (prot_verify_write(scp, lba, num, ei_lba)) {

		case 1: /* Guard tag error */

			if (scp->prot_flags & SCSI_PROT_GUARD_CHECK) {

				write_unlock(macc_lckp);

				sdeb_write_unlock(sip);

				mk_sense_buffer(scp, ILLEGAL_REQUEST, 0x10, 1);

				return illegal_condition_result;

			} else if (scp->cmnd[1] >> 5 != 3) { /* WRPROTECT != 3 */

				write_unlock(macc_lckp);

				sdeb_write_unlock(sip);

				mk_sense_buffer(scp, ABORTED_COMMAND, 0x10, 1);

				return check_condition_result;

			}

			break;

		case 3: /* Reference tag error */

			if (scp->prot_flags & SCSI_PROT_REF_CHECK) {

				write_unlock(macc_lckp);

				sdeb_write_unlock(sip);

				mk_sense_buffer(scp, ILLEGAL_REQUEST, 0x10, 3);

				return illegal_condition_result;

			} else if (scp->cmnd[1] >> 5 != 3) { /* WRPROTECT != 3 */

				write_unlock(macc_lckp);

				sdeb_write_unlock(sip);

				mk_sense_buffer(scp, ABORTED_COMMAND, 0x10, 3);

				return check_condition_result;

			}
@@ -3532,7 +3575,7 @@ static int resp_write_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	/* If ZBC zone then bump its write pointer */

	if (sdebug_dev_is_zoned(devip))

		zbc_inc_wp(devip, lba, num);

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	if (unlikely(-1 == ret))

		return DID_ERROR << 16;

	else if (unlikely(sdebug_verbose &&
@@ -3572,7 +3615,6 @@ static int resp_write_scat(struct scsi_cmnd *scp, 
	u8 *lrdp = NULL;

	u8 *up;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = &sip->macc_lck;

	u8 wrprotect;

	u16 lbdof, num_lrd, k;

	u32 num, num_by, bt_len, lbdof_blen, sg_off, cum_lb;
@@ -3640,7 +3682,7 @@ static int resp_write_scat(struct scsi_cmnd *scp, 
		goto err_out;

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);

	sg_off = lbdof_blen;

	/* Spec says Buffer xfer Length field in number of LBs in dout */

	cum_lb = 0;
@@ -3722,7 +3764,7 @@ static int resp_write_scat(struct scsi_cmnd *scp, 
	}

	ret = 0;

err_out_unlock:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

err_out:

	kfree(lrdp);

	return ret;
@@ -3739,15 +3781,14 @@ static int resp_write_same(struct scsi_cmnd *scp, u64 lba, u32 num, 
	int ret;

	struct sdeb_store_info *sip = devip2sip((struct sdebug_dev_info *)

						scp->device->hostdata, true);

	rwlock_t *macc_lckp = &sip->macc_lck;

	u8 *fs1p;

	u8 *fsp;



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	ret = check_device_access_params(scp, lba, num, true);

	if (ret) {

		write_unlock(macc_lckp);

		sdeb_write_unlock(sip);

		return ret;

	}
@@ -3767,7 +3808,7 @@ static int resp_write_same(struct scsi_cmnd *scp, u64 lba, u32 num, 
		ret = fetch_to_dev_buffer(scp, fs1p, lb_size);



	if (-1 == ret) {

		write_unlock(&sip->macc_lck);

		sdeb_write_unlock(sip);

		return DID_ERROR << 16;

	} else if (sdebug_verbose && !ndob && (ret < lb_size))

		sdev_printk(KERN_INFO, scp->device,
@@ -3786,7 +3827,7 @@ static int resp_write_same(struct scsi_cmnd *scp, u64 lba, u32 num, 
	if (sdebug_dev_is_zoned(devip))

		zbc_inc_wp(devip, lba, num);

out:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);



	return 0;

}
@@ -3899,7 +3940,6 @@ static int resp_comp_write(struct scsi_cmnd *scp, 
	u8 *cmd = scp->cmnd;

	u8 *arr;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = &sip->macc_lck;

	u64 lba;

	u32 dnum;

	u32 lb_size = sdebug_sector_size;
@@ -3932,7 +3972,7 @@ static int resp_comp_write(struct scsi_cmnd *scp, 
		return check_condition_result;

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	ret = do_dout_fetch(scp, dnum, arr);

	if (ret == -1) {
@@ -3950,7 +3990,7 @@ static int resp_comp_write(struct scsi_cmnd *scp, 
	if (scsi_debug_lbp())

		map_region(sip, lba, num);

cleanup:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	kfree(arr);

	return retval;

}
@@ -3966,7 +4006,6 @@ static int resp_unmap(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	unsigned char *buf;

	struct unmap_block_desc *desc;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = &sip->macc_lck;

	unsigned int i, payload_len, descriptors;

	int ret;
@@ -3995,7 +4034,7 @@ static int resp_unmap(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 


	desc = (void *)&buf[8];



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	for (i = 0 ; i < descriptors ; i++) {

		unsigned long long lba = get_unaligned_be64(&desc[i].lba);
@@ -4011,7 +4050,7 @@ static int resp_unmap(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	ret = 0;



out:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	kfree(buf);



	return ret;
@@ -4103,7 +4142,6 @@ static int resp_pre_fetch(struct scsi_cmnd *scp, 
	u32 nblks;

	u8 *cmd = scp->cmnd;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = &sip->macc_lck;

	u8 *fsp = sip->storep;



	if (cmd[0] == PRE_FETCH) {	/* 10 byte cdb */
@@ -4125,12 +4163,12 @@ static int resp_pre_fetch(struct scsi_cmnd *scp, 
		rest = block + nblks - sdebug_store_sectors;



	/* Try to bring the PRE-FETCH range into CPU's cache */

	read_lock(macc_lckp);

	sdeb_read_lock(sip);

	prefetch_range(fsp + (sdebug_sector_size * block),

		       (nblks - rest) * sdebug_sector_size);

	if (rest)

		prefetch_range(fsp, rest * sdebug_sector_size);

	read_unlock(macc_lckp);

	sdeb_read_unlock(sip);

fini:

	if (cmd[1] & 0x2)

		res = SDEG_RES_IMMED_MASK;
@@ -4251,7 +4289,6 @@ static int resp_verify(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	u8 *arr;

	u8 *cmd = scp->cmnd;

	struct sdeb_store_info *sip = devip2sip(devip, true);

	rwlock_t *macc_lckp = &sip->macc_lck;



	bytchk = (cmd[1] >> 1) & 0x3;

	if (bytchk == 0) {
@@ -4290,7 +4327,7 @@ static int resp_verify(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
		return check_condition_result;

	}

	/* Not changing store, so only need read access */

	read_lock(macc_lckp);

	sdeb_read_lock(sip);



	ret = do_dout_fetch(scp, a_num, arr);

	if (ret == -1) {
@@ -4312,7 +4349,7 @@ static int resp_verify(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
		goto cleanup;

	}

cleanup:

	read_unlock(macc_lckp);

	sdeb_read_unlock(sip);

	kfree(arr);

	return ret;

}
@@ -4332,7 +4369,6 @@ static int resp_report_zones(struct scsi_cmnd *scp, 
	u8 *cmd = scp->cmnd;

	struct sdeb_zone_state *zsp;

	struct sdeb_store_info *sip = devip2sip(devip, false);

	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;



	if (!sdebug_dev_is_zoned(devip)) {

		mk_sense_invalid_opcode(scp);
@@ -4361,7 +4397,7 @@ static int resp_report_zones(struct scsi_cmnd *scp, 
		return check_condition_result;

	}



	read_lock(macc_lckp);

	sdeb_read_lock(sip);



	desc = arr + 64;

	for (i = 0; i < max_zones; i++) {
@@ -4449,7 +4485,7 @@ static int resp_report_zones(struct scsi_cmnd *scp, 
	ret = fill_from_dev_buffer(scp, arr, min_t(u32, alloc_len, rep_len));



fini:

	read_unlock(macc_lckp);

	sdeb_read_unlock(sip);

	kfree(arr);

	return ret;

}
@@ -4475,14 +4511,13 @@ static int resp_open_zone(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	struct sdeb_zone_state *zsp;

	bool all = cmd[14] & 0x01;

	struct sdeb_store_info *sip = devip2sip(devip, false);

	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;



	if (!sdebug_dev_is_zoned(devip)) {

		mk_sense_invalid_opcode(scp);

		return check_condition_result;

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	if (all) {

		/* Check if all closed zones can be open */
@@ -4531,7 +4566,7 @@ static int resp_open_zone(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 


	zbc_open_zone(devip, zsp, true);

fini:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	return res;

}
@@ -4552,14 +4587,13 @@ static int resp_close_zone(struct scsi_cmnd *scp, 
	struct sdeb_zone_state *zsp;

	bool all = cmd[14] & 0x01;

	struct sdeb_store_info *sip = devip2sip(devip, false);

	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;



	if (!sdebug_dev_is_zoned(devip)) {

		mk_sense_invalid_opcode(scp);

		return check_condition_result;

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	if (all) {

		zbc_close_all(devip);
@@ -4588,7 +4622,7 @@ static int resp_close_zone(struct scsi_cmnd *scp, 


	zbc_close_zone(devip, zsp);

fini:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	return res;

}
@@ -4625,14 +4659,13 @@ static int resp_finish_zone(struct scsi_cmnd *scp, 
	u8 *cmd = scp->cmnd;

	bool all = cmd[14] & 0x01;

	struct sdeb_store_info *sip = devip2sip(devip, false);

	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;



	if (!sdebug_dev_is_zoned(devip)) {

		mk_sense_invalid_opcode(scp);

		return check_condition_result;

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	if (all) {

		zbc_finish_all(devip);
@@ -4661,7 +4694,7 @@ static int resp_finish_zone(struct scsi_cmnd *scp, 


	zbc_finish_zone(devip, zsp, true);

fini:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	return res;

}
@@ -4706,14 +4739,13 @@ static int resp_rwp_zone(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 
	u8 *cmd = scp->cmnd;

	bool all = cmd[14] & 0x01;

	struct sdeb_store_info *sip = devip2sip(devip, false);

	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;



	if (!sdebug_dev_is_zoned(devip)) {

		mk_sense_invalid_opcode(scp);

		return check_condition_result;

	}



	write_lock(macc_lckp);

	sdeb_write_lock(sip);



	if (all) {

		zbc_rwp_all(devip);
@@ -4741,7 +4773,7 @@ static int resp_rwp_zone(struct scsi_cmnd *scp, struct sdebug_dev_info *devip) 


	zbc_rwp_zone(devip, zsp);

fini:

	write_unlock(macc_lckp);

	sdeb_write_unlock(sip);

	return res;

}
@@ -5740,6 +5772,7 @@ module_param_named(medium_error_start, sdebug_medium_error_start, int, 
		   S_IRUGO | S_IWUSR);

module_param_named(ndelay, sdebug_ndelay, int, S_IRUGO | S_IWUSR);

module_param_named(no_lun_0, sdebug_no_lun_0, int, S_IRUGO | S_IWUSR);

module_param_named(no_rwlock, sdebug_no_rwlock, bool, S_IRUGO | S_IWUSR);

module_param_named(no_uld, sdebug_no_uld, int, S_IRUGO);

module_param_named(num_parts, sdebug_num_parts, int, S_IRUGO);

module_param_named(num_tgts, sdebug_num_tgts, int, S_IRUGO | S_IWUSR);
@@ -5812,6 +5845,7 @@ MODULE_PARM_DESC(medium_error_count, "count of sectors to return follow on MEDIU 
MODULE_PARM_DESC(medium_error_start, "starting sector number to return MEDIUM error");

MODULE_PARM_DESC(ndelay, "response delay in nanoseconds (def=0 -> ignore)");

MODULE_PARM_DESC(no_lun_0, "no LU number 0 (def=0 -> have lun 0)");

MODULE_PARM_DESC(no_rwlock, "don't protect user data reads+writes (def=0)");

MODULE_PARM_DESC(no_uld, "stop ULD (e.g. sd driver) attaching (def=0))");

MODULE_PARM_DESC(num_parts, "number of partitions(def=0)");

MODULE_PARM_DESC(num_tgts, "number of targets per host to simulate(def=1)");
@@ -6374,6 +6408,23 @@ static ssize_t host_max_queue_show(struct device_driver *ddp, char *buf) 
	return scnprintf(buf, PAGE_SIZE, "%d\n", sdebug_host_max_queue);

}



static ssize_t no_rwlock_show(struct device_driver *ddp, char *buf)

{

	return scnprintf(buf, PAGE_SIZE, "%d\n", sdebug_no_rwlock);

}



static ssize_t no_rwlock_store(struct device_driver *ddp, const char *buf, size_t count)

{

	bool v;



	if (kstrtobool(buf, &v))

		return -EINVAL;



	sdebug_no_rwlock = v;

	return count;

}

static DRIVER_ATTR_RW(no_rwlock);



/*

 * Since this is used for .can_queue, and we get the hc_idx tag from the bitmap

 * in range [0, sdebug_host_max_queue), we can't change it.
@@ -6739,6 +6790,7 @@ static struct attribute *sdebug_drv_attrs[] = { 
	&driver_attr_lun_format.attr,

	&driver_attr_max_luns.attr,

	&driver_attr_max_queue.attr,

	&driver_attr_no_rwlock.attr,

	&driver_attr_no_uld.attr,

	&driver_attr_scsi_level.attr,

	&driver_attr_virtual_gb.attr,