[v3,1/4] scsi: core: Add new helper to iterate all devices of host
Commit Message
shost_for_each_device() would skip devices which is in SDEV_CANCEL or
SDEV_DEL state, for some scenarios, we donot want to skip these devices,
so add a new macro shost_for_each_device_include_deleted() to handle it.
Following changes are introduced:
1. Rework scsi_device_get(), add new helper __scsi_device_get() which
determine if skip deleted scsi_device by parameter "skip_deleted".
2. Add new parameter "skip_deleted" to __scsi_iterate_devices() which
is used when calling __scsi_device_get()
3. Update shost_for_each_device() to call __scsi_iterate_devices() with
"skip_deleted" true
4. Add new macro shost_for_each_device_include_deleted() which call
__scsi_iterate_devices() with "skip_deleted" false
Signed-off-by: Wenchao Hao <haowenchao2@huawei.com>
---
drivers/scsi/scsi.c | 46 ++++++++++++++++++++++++++------------
include/scsi/scsi_device.h | 25 ++++++++++++++++++---
2 files changed, 54 insertions(+), 17 deletions(-)
Comments
Hi Wenchao,
kernel test robot noticed the following build warnings:
[auto build test WARNING on mkp-scsi/for-next]
[also build test WARNING on jejb-scsi/for-next linus/master v6.6-rc6 next-20231017]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Wenchao-Hao/scsi-core-Add-new-helper-to-iterate-all-devices-of-host/20231017-140049
base: https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git for-next
patch link: https://lore.kernel.org/r/20231016020314.1269636-2-haowenchao2%40huawei.com
patch subject: [PATCH v3 1/4] scsi: core: Add new helper to iterate all devices of host
config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20231017/202310172345.jViTGPKD-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231017/202310172345.jViTGPKD-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202310172345.jViTGPKD-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/scsi/scsi.c:767: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* helper for shost_for_each_device, see that for documentation
vim +767 drivers/scsi/scsi.c
765
766 /**
> 767 * helper for shost_for_each_device, see that for documentation
768 * @skip_deleted: if true, sdev in progress of removing would be skipped
769 */
770 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
771 struct scsi_device *prev,
772 bool skip_deleted)
773 {
774 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
775 struct scsi_device *next = NULL;
776 unsigned long flags;
777
778 spin_lock_irqsave(shost->host_lock, flags);
779 while (list->next != &shost->__devices) {
780 next = list_entry(list->next, struct scsi_device, siblings);
781 /* skip devices that we can't get a reference to */
782 if (!__scsi_device_get(next, skip_deleted))
783 break;
784 next = NULL;
785 list = list->next;
786 }
787 spin_unlock_irqrestore(shost->host_lock, flags);
788
789 if (prev)
790 scsi_device_put(prev);
791 return next;
792 }
793 EXPORT_SYMBOL(__scsi_iterate_devices);
794
@@ -704,20 +704,18 @@ int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
return 0;
}
-/**
- * scsi_device_get - get an additional reference to a scsi_device
+/*
+ * __scsi_device_get - get an additional reference to a scsi_device
* @sdev: device to get a reference to
- *
- * Description: Gets a reference to the scsi_device and increments the use count
- * of the underlying LLDD module. You must hold host_lock of the
- * parent Scsi_Host or already have a reference when calling this.
- *
- * This will fail if a device is deleted or cancelled, or when the LLD module
- * is in the process of being unloaded.
+ * @skip_deleted: when true, would return failed if device is deleted
*/
-int scsi_device_get(struct scsi_device *sdev)
+static int __scsi_device_get(struct scsi_device *sdev, bool skip_deleted)
{
- if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
+ /*
+ * if skip_deleted is true and device is in removing, return failed
+ */
+ if (skip_deleted &&
+ (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL))
goto fail;
if (!try_module_get(sdev->host->hostt->module))
goto fail;
@@ -730,6 +728,22 @@ int scsi_device_get(struct scsi_device *sdev)
fail:
return -ENXIO;
}
+
+/**
+ * scsi_device_get - get an additional reference to a scsi_device
+ * @sdev: device to get a reference to
+ *
+ * Description: Gets a reference to the scsi_device and increments the use count
+ * of the underlying LLDD module. You must hold host_lock of the
+ * parent Scsi_Host or already have a reference when calling this.
+ *
+ * This will fail if a device is deleted or cancelled, or when the LLD module
+ * is in the process of being unloaded.
+ */
+int scsi_device_get(struct scsi_device *sdev)
+{
+ return __scsi_device_get(sdev, 0);
+}
EXPORT_SYMBOL(scsi_device_get);
/**
@@ -749,9 +763,13 @@ void scsi_device_put(struct scsi_device *sdev)
}
EXPORT_SYMBOL(scsi_device_put);
-/* helper for shost_for_each_device, see that for documentation */
+/**
+ * helper for shost_for_each_device, see that for documentation
+ * @skip_deleted: if true, sdev in progress of removing would be skipped
+ */
struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
- struct scsi_device *prev)
+ struct scsi_device *prev,
+ bool skip_deleted)
{
struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
struct scsi_device *next = NULL;
@@ -761,7 +779,7 @@ struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
while (list->next != &shost->__devices) {
next = list_entry(list->next, struct scsi_device, siblings);
/* skip devices that we can't get a reference to */
- if (!scsi_device_get(next))
+ if (!__scsi_device_get(next, skip_deleted))
break;
next = NULL;
list = list->next;
@@ -390,7 +390,8 @@ extern void __starget_for_each_device(struct scsi_target *, void *,
/* only exposed to implement shost_for_each_device */
extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,
- struct scsi_device *);
+ struct scsi_device *,
+ bool);
/**
* shost_for_each_device - iterate over all devices of a host
@@ -400,11 +401,29 @@ extern struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *,
* Iterator that returns each device attached to @shost. This loop
* takes a reference on each device and releases it at the end. If
* you break out of the loop, you must call scsi_device_put(sdev).
+ *
+ * Note: this macro would skip sdev which is in progress of removing
*/
#define shost_for_each_device(sdev, shost) \
- for ((sdev) = __scsi_iterate_devices((shost), NULL); \
+ for ((sdev) = __scsi_iterate_devices((shost), NULL, 1); \
+ (sdev); \
+ (sdev) = __scsi_iterate_devices((shost), (sdev), 1))
+
+/*
+ * shost_for_each_device_include_deleted- iterate over all devices of a host
+ * @sdev: the &struct scsi_device to use as a cursor
+ * @shost: the &struct scsi_host to iterate over
+ *
+ * Iterator that returns each device attached to @shost. This loop
+ * takes a reference on each device and releases it at the end. If
+ * you break out of the loop, you must call scsi_device_put(sdev).
+ *
+ * Note: this macro would include sdev which is in progress of removing
+ */
+#define shost_for_each_device_include_deleted(sdev, shost) \
+ for ((sdev) = __scsi_iterate_devices((shost), NULL, 0); \
(sdev); \
- (sdev) = __scsi_iterate_devices((shost), (sdev)))
+ (sdev) = __scsi_iterate_devices((shost), (sdev), 0))
/**
* __shost_for_each_device - iterate over all devices of a host (UNLOCKED)