From: Douglas Gilbert <dgilbert@interlog.com>
To: linux-scsi@vger.kernel.org
Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, hare@suse.de
Subject: [RFC v2 6/6] scsi: count number of targets
Date: Sun, 24 May 2020 11:58:14 -0400 [thread overview]
Message-ID: <20200524155814.5895-7-dgilbert@interlog.com> (raw)
In-Reply-To: <20200524155814.5895-1-dgilbert@interlog.com>
If less than 2 used to flatten iteration in __scsi_device_lookup().
The majority of hosts will have 1 target and 1 LU (device).
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
---
drivers/scsi/scsi.c | 12 ++++--------
drivers/scsi/scsi_scan.c | 5 ++++-
include/scsi/scsi_host.h | 1 +
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 1b1fc8d4e5c2..6acd85ce21dd 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -557,10 +557,6 @@ struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
unsigned long flags, l_idx;
spin_lock_irqsave(shost->host_lock, flags);
- if (xa_empty(&shost->__devices)) {
- next = NULL;
- goto unlock;
- }
do {
if (!next) { /* get first element iff first iteration */
l_idx = 0;
@@ -578,7 +574,6 @@ struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
break;
}
} while (next);
-unlock:
spin_unlock_irqrestore(shost->host_lock, flags);
if (prev)
@@ -818,8 +813,9 @@ struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
if (xa_empty(&shost->__devices))
return NULL;
- if (xa_empty(&shost->__targets))
- goto inconsistent;
+ if (shost->num_targets < 2)
+ goto flat_iteration;
+
xa_for_each(&shost->__targets, l_idx, starg) {
if (!(starg->id == id && starg->channel == channel))
continue;
@@ -830,7 +826,7 @@ struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
}
}
return NULL;
-inconsistent:
+flat_iteration:
xa_for_each_marked(&shost->__devices, m_idx, sdev,
SCSI_XA_NON_SDEV_DEL) {
if (sdev->id == id && sdev->channel == channel &&
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index c055ee083ea9..d665da2b01a4 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -320,7 +320,9 @@ static void scsi_target_destroy(struct scsi_target *starget)
shost->hostt->target_destroy(starget);
/* XARRAY: was list_del_init(); why the _init ? */
e_starg = xa_erase(&shost->__targets, starget->sh_idx);
- if (e_starg != starget)
+ if (e_starg == starget)
+ --shost->num_targets;
+ else
pr_err("%s: bad xa_erase()\n", __func__);
spin_unlock_irqrestore(shost->host_lock, flags);
put_device(dev);
@@ -465,6 +467,7 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,
return NULL;
}
starget->sh_idx = u_idx;
+ ++shost->num_targets;
spin_unlock_irqrestore(shost->host_lock, flags);
/* allocate and add */
transport_setup_device(dev);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 0e94b1feb8e9..f49298a4c452 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -528,6 +528,7 @@ struct Scsi_Host {
*/
struct xarray __devices; /* array of scsi_debug objs */
struct xarray __targets; /* array of scsi_target objs */
+ int num_targets; /* modified under host_lock */
struct list_head starved_list;
--
2.25.1
prev parent reply other threads:[~2020-05-24 15:58 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-24 15:58 [RFC v2 0/6] scsi: rework mid-layer with xarrays Douglas Gilbert
2020-05-24 15:58 ` [RFC v2 1/6] scsi: xarray hctl Douglas Gilbert
2020-05-25 6:57 ` Hannes Reinecke
2020-05-25 16:30 ` Douglas Gilbert
2020-05-25 17:40 ` Matthew Wilcox
2020-05-26 2:01 ` Douglas Gilbert
2020-05-26 3:01 ` Matthew Wilcox
2020-05-26 7:24 ` Hannes Reinecke
2020-05-26 6:21 ` Hannes Reinecke
2020-05-26 14:27 ` Matthew Wilcox
2020-05-26 17:53 ` Hannes Reinecke
2020-05-26 18:39 ` Matthew Wilcox
2020-05-26 19:28 ` James Bottomley
2020-05-26 19:10 ` Douglas Gilbert
2020-05-26 20:27 ` Douglas Gilbert
2020-05-27 2:53 ` Douglas Gilbert
2020-05-24 15:58 ` [RFC v2 2/6] scsi: xarray, iterations on scsi_target Douglas Gilbert
2020-05-25 7:06 ` Hannes Reinecke
2020-05-24 15:58 ` [RFC v2 3/6] scsi: xarray mark sdev_del state Douglas Gilbert
2020-05-25 7:00 ` Hannes Reinecke
2020-05-25 16:47 ` Douglas Gilbert
2020-05-24 15:58 ` [RFC v2 4/6] scsi: improve scsi_device_lookup Douglas Gilbert
2020-05-25 7:07 ` Hannes Reinecke
2020-05-24 15:58 ` [RFC v2 5/6] scsi: add __scsi_target_lookup Douglas Gilbert
2020-05-24 15:58 ` Douglas Gilbert [this message]
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