Commit 3cf7b233 authored by Mike Christie's avatar Mike Christie Committed by James Bottomley

[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
...@@ -1893,29 +1893,48 @@ EXPORT_SYMBOL_GPL(iscsi_host_free); ...@@ -1893,29 +1893,48 @@ EXPORT_SYMBOL_GPL(iscsi_host_free);
* *
* This can be used by software iscsi_transports that allocate * This can be used by software iscsi_transports that allocate
* a session per scsi host. * 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 * struct iscsi_cls_session *
iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost, 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) uint32_t initial_cmdsn, unsigned int id)
{ {
struct iscsi_session *session; struct iscsi_session *session;
struct iscsi_cls_session *cls_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) if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
scsi_cmds_max = ISCSI_MGMT_CMDS_MAX; printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
if ((scsi_cmds_max + ISCSI_MGMT_CMDS_MAX) >= ISCSI_MGMT_ITT_OFFSET) { "must be a power of two that is at least %d.\n",
printk(KERN_ERR "iscsi: invalid can_queue of %d. " total_cmds, ISCSI_TOTAL_CMDS_MIN);
"can_queue must be less than %d.\n", return NULL;
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_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, cls_session = iscsi_alloc_session(shost, iscsit,
sizeof(struct iscsi_session)); sizeof(struct iscsi_session));
...@@ -1928,8 +1947,8 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost, ...@@ -1928,8 +1947,8 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
session->fast_abort = 1; session->fast_abort = 1;
session->lu_reset_timeout = 15; session->lu_reset_timeout = 15;
session->abort_timeout = 10; session->abort_timeout = 10;
session->scsi_cmds_max = scsi_cmds_max; session->scsi_cmds_max = scsi_cmds;
session->cmds_max = cmds_max; session->cmds_max = total_cmds;
session->queued_cmdsn = session->cmdsn = initial_cmdsn; session->queued_cmdsn = session->cmdsn = initial_cmdsn;
session->exp_cmdsn = initial_cmdsn + 1; session->exp_cmdsn = initial_cmdsn + 1;
session->max_cmdsn = initial_cmdsn + 1; session->max_cmdsn = initial_cmdsn + 1;
......
...@@ -52,9 +52,7 @@ struct device; ...@@ -52,9 +52,7 @@ struct device;
#endif #endif
#define ISCSI_DEF_XMIT_CMDS_MAX 128 /* must be power of 2 */ #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_CMDS_MAX 15
#define ISCSI_MGMT_ITT_OFFSET 0xa00
#define ISCSI_DEF_CMD_PER_LUN 32 #define ISCSI_DEF_CMD_PER_LUN 32
#define ISCSI_MAX_CMD_PER_LUN 128 #define ISCSI_MAX_CMD_PER_LUN 128
...@@ -72,7 +70,10 @@ enum { ...@@ -72,7 +70,10 @@ enum {
/* Connection suspend "bit" */ /* Connection suspend "bit" */
#define ISCSI_SUSPEND_BIT 1 #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_SHIFT 28
#define ISCSI_AGE_MASK (0xf << ISCSI_AGE_SHIFT) #define ISCSI_AGE_MASK (0xf << ISCSI_AGE_SHIFT)
......
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