scsi: use container_of to get at device handler private data

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>

5 files changed, 37 insertions, 61 deletions

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 9115c31f26e9..d9781045c4ee 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -62,6 +62,7 @@
 #define ALUA_OPTIMIZE_STPG              1
 
 struct alua_dh_data {
+        struct scsi_dh_data     dh_data;
         int                     group_id;
         int                     rel_port;
         int                     tpgs;
@@ -87,9 +88,7 @@ static int alua_check_sense(struct scsi_device *, struct scsi_sense_hdr *);
 
 static inline struct alua_dh_data *get_alua_data(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
-        BUG_ON(scsi_dh_data == NULL);
-        return ((struct alua_dh_data *) scsi_dh_data->buf);
+        return container_of(sdev->scsi_dh_data, struct alua_dh_data, dh_data);
 }
 
 static int realloc_buffer(struct alua_dh_data *h, unsigned len)
@@ -846,21 +845,18 @@ static struct scsi_device_handler alua_dh = {
  */
 static int alua_bus_attach(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data;
         struct alua_dh_data *h;
         unsigned long flags;
         int err = SCSI_DH_OK;
 
-        scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
-                               + sizeof(*h) , GFP_KERNEL);
-        if (!scsi_dh_data) {
+        h = kzalloc(sizeof(*h) , GFP_KERNEL);
+        if (!h) {
                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
                             ALUA_DH_NAME);
                 return -ENOMEM;
         }
 
-        scsi_dh_data->scsi_dh = &alua_dh;
-        h = (struct alua_dh_data *) scsi_dh_data->buf;
+        h->dh_data.scsi_dh = &alua_dh;
         h->tpgs = TPGS_MODE_UNINITIALIZED;
         h->state = TPGS_STATE_OPTIMIZED;
         h->group_id = -1;
@@ -874,14 +870,14 @@ static int alua_bus_attach(struct scsi_device *sdev)
                 goto failed;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        sdev->scsi_dh_data = scsi_dh_data;
+        sdev->scsi_dh_data = &h->dh_data;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
         sdev_printk(KERN_NOTICE, sdev, "%s: Attached\n", ALUA_DH_NAME);
 
         return 0;
 
 failed:
-        kfree(scsi_dh_data);
+        kfree(h);
         sdev_printk(KERN_ERR, sdev, "%s: not attached\n", ALUA_DH_NAME);
         return -EINVAL;
 }
@@ -892,19 +888,16 @@ failed:
  */
 static void alua_bus_detach(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data;
-        struct alua_dh_data *h;
+        struct alua_dh_data *h = get_alua_data(sdev);
         unsigned long flags;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        scsi_dh_data = sdev->scsi_dh_data;
         sdev->scsi_dh_data = NULL;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
-        h = (struct alua_dh_data *) scsi_dh_data->buf;
         if (h->buff && h->inq != h->buff)
                 kfree(h->buff);
-        kfree(scsi_dh_data);
+        kfree(h);
         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
 }
 
diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
index 153b4c3547a2..c2e26cdef21a 100644
--- a/drivers/scsi/device_handler/scsi_dh_emc.c
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -72,6 +72,7 @@ static const char * lun_state[] =
 };
 
 struct clariion_dh_data {
+        struct scsi_dh_data dh_data;
         /*
          * Flags:
          *  CLARIION_SHORT_TRESPASS
@@ -116,9 +117,8 @@ struct clariion_dh_data {
 static inline struct clariion_dh_data
                         *get_clariion_data(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
-        BUG_ON(scsi_dh_data == NULL);
-        return ((struct clariion_dh_data *) scsi_dh_data->buf);
+        return container_of(sdev->scsi_dh_data, struct clariion_dh_data,
+                        dh_data);
 }
 
 /*
@@ -665,21 +665,18 @@ static struct scsi_device_handler clariion_dh = {
 
 static int clariion_bus_attach(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data;
         struct clariion_dh_data *h;
         unsigned long flags;
         int err;
 
-        scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
-                               + sizeof(*h) , GFP_KERNEL);
-        if (!scsi_dh_data) {
+        h = kzalloc(sizeof(*h) , GFP_KERNEL);
+        if (!h) {
                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
                             CLARIION_NAME);
                 return -ENOMEM;
         }
 
-        scsi_dh_data->scsi_dh = &clariion_dh;
-        h = (struct clariion_dh_data *) scsi_dh_data->buf;
+        h->dh_data.scsi_dh = &clariion_dh;
         h->lun_state = CLARIION_LUN_UNINITIALIZED;
         h->default_sp = CLARIION_UNBOUND_LU;
         h->current_sp = CLARIION_UNBOUND_LU;
@@ -693,7 +690,7 @@ static int clariion_bus_attach(struct scsi_device *sdev)
                 goto failed;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        sdev->scsi_dh_data = scsi_dh_data;
+        sdev->scsi_dh_data = &h->dh_data;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
         sdev_printk(KERN_INFO, sdev,
@@ -705,7 +702,7 @@ static int clariion_bus_attach(struct scsi_device *sdev)
         return 0;
 
 failed:
-        kfree(scsi_dh_data);
+        kfree(h);
         sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
                     CLARIION_NAME);
         return -EINVAL;
@@ -713,18 +710,17 @@ failed:
 
 static void clariion_bus_detach(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data;
+        struct clariion_dh_data *h = get_clariion_data(sdev);
         unsigned long flags;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        scsi_dh_data = sdev->scsi_dh_data;
         sdev->scsi_dh_data = NULL;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n",
                     CLARIION_NAME);
 
-        kfree(scsi_dh_data);
+        kfree(h);
 }
 
 static int __init clariion_init(void)
diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index cf36557a1d4d..37dedcae0aa4 100644
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -38,6 +38,7 @@
 #define HP_SW_PATH_PASSIVE              1
 
 struct hp_sw_dh_data {
+        struct scsi_dh_data dh_data;
         unsigned char sense[SCSI_SENSE_BUFFERSIZE];
         int path_state;
         int retries;
@@ -51,9 +52,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *);
 
 static inline struct hp_sw_dh_data *get_hp_sw_data(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
-        BUG_ON(scsi_dh_data == NULL);
-        return ((struct hp_sw_dh_data *) scsi_dh_data->buf);
+        return container_of(sdev->scsi_dh_data, struct hp_sw_dh_data, dh_data);
 }
 
 /*
@@ -354,21 +353,18 @@ static struct scsi_device_handler hp_sw_dh = {
 
 static int hp_sw_bus_attach(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data;
         struct hp_sw_dh_data *h;
         unsigned long flags;
         int ret;
 
-        scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
-                               + sizeof(*h) , GFP_KERNEL);
-        if (!scsi_dh_data) {
+        h = kzalloc(sizeof(*h), GFP_KERNEL);
+        if (!h) {
                 sdev_printk(KERN_ERR, sdev, "%s: Attach Failed\n",
                             HP_SW_NAME);
                 return -ENOMEM;
         }
 
-        scsi_dh_data->scsi_dh = &hp_sw_dh;
-        h = (struct hp_sw_dh_data *) scsi_dh_data->buf;
+        h->dh_data.scsi_dh = &hp_sw_dh;
         h->path_state = HP_SW_PATH_UNINITIALIZED;
         h->retries = HP_SW_RETRIES;
         h->sdev = sdev;
@@ -378,7 +374,7 @@ static int hp_sw_bus_attach(struct scsi_device *sdev)
                 goto failed;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        sdev->scsi_dh_data = scsi_dh_data;
+        sdev->scsi_dh_data = &h->dh_data;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
         sdev_printk(KERN_INFO, sdev, "%s: attached to %s path\n",
@@ -388,7 +384,7 @@ static int hp_sw_bus_attach(struct scsi_device *sdev)
         return 0;
 
 failed:
-        kfree(scsi_dh_data);
+        kfree(h);
         sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
                     HP_SW_NAME);
         return -EINVAL;
@@ -396,17 +392,16 @@ failed:
 
 static void hp_sw_bus_detach( struct scsi_device *sdev )
 {
-        struct scsi_dh_data *scsi_dh_data;
+        struct hp_sw_dh_data *h = get_hp_sw_data(sdev);
         unsigned long flags;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        scsi_dh_data = sdev->scsi_dh_data;
         sdev->scsi_dh_data = NULL;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", HP_SW_NAME);
 
-        kfree(scsi_dh_data);
+        kfree(h);
 }
 
 static int __init hp_sw_init(void)
diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index b850954c4e22..ef8caaaad76f 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -181,6 +181,7 @@ struct c2_inquiry {
 };
 
 struct rdac_dh_data {
+        struct scsi_dh_data     dh_data;
         struct rdac_controller  *ctlr;
 #define UNINITIALIZED_LUN       (1 << 8)
         unsigned                lun;
@@ -261,9 +262,7 @@ do { \
 
 static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
-        BUG_ON(scsi_dh_data == NULL);
-        return ((struct rdac_dh_data *) scsi_dh_data->buf);
+        return container_of(sdev->scsi_dh_data, struct rdac_dh_data, dh_data);
 }
 
 static struct request *get_rdac_req(struct scsi_device *sdev,
@@ -842,23 +841,20 @@ static struct scsi_device_handler rdac_dh = {
 
 static int rdac_bus_attach(struct scsi_device *sdev)
 {
-        struct scsi_dh_data *scsi_dh_data;
         struct rdac_dh_data *h;
         unsigned long flags;
         int err;
         char array_name[ARRAY_LABEL_LEN];
         char array_id[UNIQUE_ID_LEN];
 
-        scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
-                               + sizeof(*h) , GFP_KERNEL);
-        if (!scsi_dh_data) {
+        h = kzalloc(sizeof(*h) , GFP_KERNEL);
+        if (!h) {
                 sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
                             RDAC_NAME);
                 return -ENOMEM;
         }
 
-        scsi_dh_data->scsi_dh = &rdac_dh;
-        h = (struct rdac_dh_data *) scsi_dh_data->buf;
+        h->dh_data.scsi_dh = &rdac_dh;
         h->lun = UNINITIALIZED_LUN;
         h->state = RDAC_STATE_ACTIVE;
 
@@ -879,7 +875,7 @@ static int rdac_bus_attach(struct scsi_device *sdev)
                 goto clean_ctlr;
 
         spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
-        sdev->scsi_dh_data = scsi_dh_data;
+        sdev->scsi_dh_data = &h->dh_data;
         spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
 
         sdev_printk(KERN_NOTICE, sdev,
@@ -895,7 +891,7 @@ clean_ctlr:
         spin_unlock(&list_lock);
 
 failed:
-        kfree(scsi_dh_data);
+        kfree(h);
         sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
                     RDAC_NAME);
         return -EINVAL;
@@ -903,12 +899,9 @@ failed:
 
 static void rdac_bus_detach( struct scsi_device *sdev )
 {
-        struct scsi_dh_data *scsi_dh_data;
-        struct rdac_dh_data *h;
+        struct rdac_dh_data *h = get_rdac_data(sdev);
         unsigned long flags;
 
-        scsi_dh_data = sdev->scsi_dh_data;
-        h = (struct rdac_dh_data *) scsi_dh_data->buf;
         if (h->ctlr && h->ctlr->ms_queued)
                 flush_workqueue(kmpath_rdacd);
 
@@ -920,7 +913,7 @@ static void rdac_bus_detach( struct scsi_device *sdev )
         if (h->ctlr)
                 kref_put(&h->ctlr->kref, release_controller);
         spin_unlock(&list_lock);
-        kfree(scsi_dh_data);
+        kfree(h);
         sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);
 }
 
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 0b18a097c1ba..04cd5ad8289e 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -228,7 +228,6 @@ struct scsi_dh_data {
         struct scsi_device_handler *scsi_dh;
         struct scsi_device *sdev;
         struct kref kref;
-        char buf[0];
 };
 
 #define to_scsi_device(d)       \