scsi: libsas: Use dynamic alloced work to avoid sas event lost

Now libsas hotplug work is static, every sas event type has its own
static work, LLDD driver queues the hotplug work into shost->work_q.  If
LLDD driver burst posts lots hotplug events to libsas, the hotplug
events may pending in the workqueue like

shost->work_q
new work[PORTE_BYTES_DMAED] --> |[PHYE_LOSS_OF_SIGNAL][PORTE_BYTES_DMAED] -> processing
                                |<-------wait worker to process-------->|

In this case, a new PORTE_BYTES_DMAED event coming, libsas try to queue
it to shost->work_q, but this work is already pending, so it would be
lost. Finally, libsas delete the related sas port and sas devices, but
LLDD driver expect libsas add the sas port and devices(last sas event).

This patch use dynamic allocated work to avoid this issue.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: Johannes Thumshirn <jthumshirn@suse.de>
CC: Ewan Milne <emilne@redhat.com>
CC: Christoph Hellwig <hch@lst.de>
CC: Tomas Henzl <thenzl@redhat.com>
CC: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 24 insertions, 3 deletions

diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index 64fa6f53cb8b..e04f6d6f5aff 100644
--- a/drivers/scsi/libsas/sas_init.c
+++ b/drivers/scsi/libsas/sas_init.c
@@ -39,6 +39,7 @@
 #include "../scsi_sas_internal.h"
 
 static struct kmem_cache *sas_task_cache;
+static struct kmem_cache *sas_event_cache;
 
 struct sas_task *sas_alloc_task(gfp_t flags)
 {
@@ -364,8 +365,6 @@ void sas_prep_resume_ha(struct sas_ha_struct *ha)
 		struct asd_sas_phy *phy = ha->sas_phy[i];
 
 		memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
-		phy->port_events_pending = 0;
-		phy->phy_events_pending = 0;
 		phy->frame_rcvd_size = 0;
 	}
 }
@@ -555,20 +554,42 @@ sas_domain_attach_transport(struct sas_domain_function_template *dft)
 }
 EXPORT_SYMBOL_GPL(sas_domain_attach_transport);
 
+
+struct asd_sas_event *sas_alloc_event(struct asd_sas_phy *phy)
+{
+	gfp_t flags = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
+
+	return kmem_cache_zalloc(sas_event_cache, flags);
+}
+
+void sas_free_event(struct asd_sas_event *event)
+{
+	kmem_cache_free(sas_event_cache, event);
+}
+
 /* ---------- SAS Class register/unregister ---------- */
 
 static int __init sas_class_init(void)
 {
 	sas_task_cache = KMEM_CACHE(sas_task, SLAB_HWCACHE_ALIGN);
 	if (!sas_task_cache)
-		return -ENOMEM;
+		goto out;
+
+	sas_event_cache = KMEM_CACHE(asd_sas_event, SLAB_HWCACHE_ALIGN);
+	if (!sas_event_cache)
+		goto free_task_kmem;
 
 	return 0;
+free_task_kmem:
+	kmem_cache_destroy(sas_task_cache);
+out:
+	return -ENOMEM;
 }
 
 static void __exit sas_class_exit(void)
 {
 	kmem_cache_destroy(sas_task_cache);
+	kmem_cache_destroy(sas_event_cache);
 }
 
 MODULE_AUTHOR("Luben Tuikov <luben_tuikov@adaptec.com>");