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Commit 3cf7b233 authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
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[SCSI] libiscsi: fix cmds_max setting 



Drivers expect that the cmds_max value they pass to the iscsi layer
is the max scsi commands  + mgmt tasks. This patch implements that
and fixes some checks for nr cmd limits.

Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@HansenPartnership.com>
parent 88dfd340

drivers/scsi/libiscsi.c

+34 −15
Original line number Diff line number Diff line
@@ -1893,29 +1893,48 @@ EXPORT_SYMBOL_GPL(iscsi_host_free); 
 *

 * This can be used by software iscsi_transports that allocate

 * a session per scsi host.

 *

 * Callers should set cmds_max to the largest total numer (mgmt + scsi) of

 * tasks they support. The iscsi layer reserves ISCSI_MGMT_CMDS_MAX tasks

 * for nop handling and login/logout requests.

 */

struct iscsi_cls_session *

iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,

		    uint16_t scsi_cmds_max, int cmd_task_size,

		    uint16_t cmds_max, int cmd_task_size,

		    uint32_t initial_cmdsn, unsigned int id)

{

	struct iscsi_session *session;

	struct iscsi_cls_session *cls_session;

	int cmd_i, cmds_max;



	int cmd_i, scsi_cmds, total_cmds = cmds_max;

	/*

	 * The iscsi layer needs some tasks for nop handling and tmfs.

	 * The iscsi layer needs some tasks for nop handling and tmfs,

	 * so the cmds_max must at least be greater than ISCSI_MGMT_CMDS_MAX

	 * + 1 command for scsi IO.

	 */

	if (scsi_cmds_max < 1)

		scsi_cmds_max = ISCSI_MGMT_CMDS_MAX;

	if ((scsi_cmds_max + ISCSI_MGMT_CMDS_MAX) >= ISCSI_MGMT_ITT_OFFSET) {

		printk(KERN_ERR "iscsi: invalid can_queue of %d. "

		       "can_queue must be less than %d.\n",

		       scsi_cmds_max,

		       ISCSI_MGMT_ITT_OFFSET - ISCSI_MGMT_CMDS_MAX);

		scsi_cmds_max = ISCSI_DEF_XMIT_CMDS_MAX;

	if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {

		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "

		       "must be a power of two that is at least %d.\n",

		       total_cmds, ISCSI_TOTAL_CMDS_MIN);

		return NULL;

	}



	if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {

		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "

		       "must be a power of 2 less than or equal to %d.\n",

		       cmds_max, ISCSI_TOTAL_CMDS_MAX);

		total_cmds = ISCSI_TOTAL_CMDS_MAX;

	}



	if (!is_power_of_2(total_cmds)) {

		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "

		       "must be a power of 2.\n", total_cmds);

		total_cmds = rounddown_pow_of_two(total_cmds);

		if (total_cmds < ISCSI_TOTAL_CMDS_MIN)

			return NULL;

		printk(KERN_INFO "iscsi: Rounding can_queue to %d.\n",

		       total_cmds);

	}

	cmds_max = roundup_pow_of_two(scsi_cmds_max + ISCSI_MGMT_CMDS_MAX);

	scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;



	cls_session = iscsi_alloc_session(shost, iscsit,

					  sizeof(struct iscsi_session));
@@ -1928,8 +1947,8 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost, 
	session->fast_abort = 1;

	session->lu_reset_timeout = 15;

	session->abort_timeout = 10;

	session->scsi_cmds_max = scsi_cmds_max;

	session->cmds_max = cmds_max;

	session->scsi_cmds_max = scsi_cmds;

	session->cmds_max = total_cmds;

	session->queued_cmdsn = session->cmdsn = initial_cmdsn;

	session->exp_cmdsn = initial_cmdsn + 1;

	session->max_cmdsn = initial_cmdsn + 1;

include/scsi/libiscsi.h

+5 −4
Original line number Diff line number Diff line
@@ -52,9 +52,7 @@ struct device; 
#endif



#define ISCSI_DEF_XMIT_CMDS_MAX	128	/* must be power of 2 */

#define ISCSI_MGMT_CMDS_MAX	16	/* must be power of 2 */



#define ISCSI_MGMT_ITT_OFFSET	0xa00

#define ISCSI_MGMT_CMDS_MAX	15



#define ISCSI_DEF_CMD_PER_LUN		32

#define ISCSI_MAX_CMD_PER_LUN		128
@@ -72,7 +70,10 @@ enum { 
/* Connection suspend "bit" */

#define ISCSI_SUSPEND_BIT		1



#define ISCSI_ITT_MASK			(0xfff)

#define ISCSI_ITT_MASK			(0x1fff)

#define ISCSI_TOTAL_CMDS_MAX		4096

/* this must be a power of two greater than ISCSI_MGMT_CMDS_MAX */

#define ISCSI_TOTAL_CMDS_MIN		16

#define ISCSI_AGE_SHIFT			28

#define ISCSI_AGE_MASK			(0xf << ISCSI_AGE_SHIFT)