This patch just breaks out the code that calculates the number
of scsi cmds that will be used for a scsi session. It also adds
a check that we don't go over the host's can_queue value.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Reviewed-by: Lee Duncan <lduncan@xxxxxxxx>
---
drivers/scsi/libiscsi.c | 86 ++++++++++++++++++++++++++---------------
include/scsi/libiscsi.h | 2 +
2 files changed, 56 insertions(+), 32 deletions(-)
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index b271d3accd2a..f64e2077754c 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -2648,6 +2648,56 @@ void iscsi_pool_free(struct iscsi_pool *q)
}
EXPORT_SYMBOL_GPL(iscsi_pool_free);
+int iscsi_host_get_max_scsi_cmds(struct Scsi_Host *shost,
+ uint16_t requested_cmds_max)
+{
+ int scsi_cmds, total_cmds = requested_cmds_max;
+
+check:
+ if (!total_cmds)
+ total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
+ /*
+ * 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 (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
+ printk(KERN_ERR "iscsi: invalid max cmds of %d. Must be a power of two that is at least %d.\n",
+ total_cmds, ISCSI_TOTAL_CMDS_MIN);
+ return -EINVAL;
+ }
+
+ if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
+ printk(KERN_INFO "iscsi: invalid max cmds of %d. Must be a power of 2 less than or equal to %d. Using %d.\n",
+ requested_cmds_max, ISCSI_TOTAL_CMDS_MAX,
+ ISCSI_TOTAL_CMDS_MAX);
+ total_cmds = ISCSI_TOTAL_CMDS_MAX;
+ }
+
+ if (!is_power_of_2(total_cmds)) {
+ total_cmds = rounddown_pow_of_two(total_cmds);
+ if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
+ printk(KERN_ERR "iscsi: invalid max cmds of %d. Must be a power of 2 greater than %d.\n", requested_cmds_max, ISCSI_TOTAL_CMDS_MIN);
+ return -EINVAL;
+ }
+
+ printk(KERN_INFO "iscsi: invalid max cmds %d. Must be a power of 2. Rounding max cmds down to %d.\n",
+ requested_cmds_max, total_cmds);
+ }
+
+ scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;
+ if (shost->can_queue && scsi_cmds > shost->can_queue) {
+ total_cmds = shost->can_queue;
+
+ printk(KERN_INFO "iscsi: requested max cmds %u is higher than driver limit. Using driver limit %u\n",
+ requested_cmds_max, shost->can_queue);
+ goto check;
+ }
+
+ return scsi_cmds;
+}
+EXPORT_SYMBOL_GPL(iscsi_host_get_max_scsi_cmds);
+
/**
* iscsi_host_add - add host to system
* @shost: scsi host
@@ -2801,7 +2851,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
struct iscsi_host *ihost = shost_priv(shost);
struct iscsi_session *session;
struct iscsi_cls_session *cls_session;
- int cmd_i, scsi_cmds, total_cmds = cmds_max;
+ int cmd_i, scsi_cmds;
unsigned long flags;
spin_lock_irqsave(&ihost->lock, flags);
@@ -2812,37 +2862,9 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
ihost->num_sessions++;
spin_unlock_irqrestore(&ihost->lock, flags);
- if (!total_cmds)
- total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
- /*
- * 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 (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);
+ scsi_cmds = iscsi_host_get_max_scsi_cmds(shost, cmds_max);
+ if (scsi_cmds < 0)
goto dec_session_count;
- }
-
- 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)
- goto dec_session_count;
- printk(KERN_INFO "iscsi: Rounding can_queue to %d.\n",
- total_cmds);
- }
- scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;
cls_session = iscsi_alloc_session(shost, iscsit,
sizeof(struct iscsi_session) +
@@ -2858,7 +2880,7 @@ iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
session->lu_reset_timeout = 15;
session->abort_timeout = 10;
session->scsi_cmds_max = scsi_cmds;
- session->cmds_max = total_cmds;
+ session->cmds_max = scsi_cmds + ISCSI_MGMT_CMDS_MAX;
session->queued_cmdsn = session->cmdsn = initial_cmdsn;
session->exp_cmdsn = initial_cmdsn + 1;
session->max_cmdsn = initial_cmdsn + 1;
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 44a9554aea62..02f966e9358f 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -395,6 +395,8 @@ extern struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
extern void iscsi_host_remove(struct Scsi_Host *shost);
extern void iscsi_host_free(struct Scsi_Host *shost);
extern int iscsi_target_alloc(struct scsi_target *starget);
+extern int iscsi_host_get_max_scsi_cmds(struct Scsi_Host *shost,
+ uint16_t requested_cmds_max);
/*
* session management
--
2.25.1
