scsi: scsi_debug: Don't hold driver host struct pointer in host->hostdata[]

This driver stores just a pointer to the driver host structure in
host->hostdata[]. Most other drivers actually have the driver host
structure allocated in host->hostdata[], but this driver is different as we
allocate that memory separately before allocating the shost memory.

However there is no need to allocate this memory only in host->hostdata[]
when we can already look up the driver host structure from shost->dma_dev,
so add a macro for this - shost_to_sdebug_host(). Rename to_sdebug_host()
-> dev_to_sdebug_host() to avoid ambiguity.

Also remove a check for !sdbg_host in find_build_dev_info(), as this cannot
be true. Other similar checks will be later removed.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20230313093114.1498305-2-john.g.garry@oracle.com
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 8553277effb3d8ea2a3bd67d2ae6cc5710a4dd60..309a0c88c7eaa08ac6c312c1c8e32199ce99d623 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -324,9 +324,12 @@ struct sdeb_store_info {
        void *map_storep;       /* provisioning map */
 };
 
-#define to_sdebug_host(d)      \
+#define dev_to_sdebug_host(d)  \
        container_of(d, struct sdebug_host_info, dev)
 
+#define shost_to_sdebug_host(shost)    \
+       dev_to_sdebug_host(shost->dma_dev)
+
 enum sdeb_defer_type {SDEB_DEFER_NONE = 0, SDEB_DEFER_HRT = 1,
                      SDEB_DEFER_WQ = 2, SDEB_DEFER_POLL = 3};
 
@@ -5166,11 +5169,7 @@ static struct sdebug_dev_info *find_build_dev_info(struct scsi_device *sdev)
        struct sdebug_dev_info *open_devip = NULL;
        struct sdebug_dev_info *devip;
 
-       sdbg_host = *(struct sdebug_host_info **)shost_priv(sdev->host);
-       if (!sdbg_host) {
-               pr_err("Host info NULL\n");
-               return NULL;
-       }
+       sdbg_host = shost_to_sdebug_host(sdev->host);
 
        list_for_each_entry(devip, &sdbg_host->dev_info_list, dev_list) {
                if ((devip->used) && (devip->channel == sdev->channel) &&
@@ -5407,7 +5406,7 @@ static int scsi_debug_target_reset(struct scsi_cmnd *SCpnt)
        hp = sdp->host;
        if (!hp)
                goto lie;
-       sdbg_host = *(struct sdebug_host_info **)shost_priv(hp);
+       sdbg_host = shost_to_sdebug_host(hp);
        if (sdbg_host) {
                list_for_each_entry(devip,
                                    &sdbg_host->dev_info_list,
@@ -5440,7 +5439,7 @@ static int scsi_debug_bus_reset(struct scsi_cmnd *SCpnt)
                sdev_printk(KERN_INFO, sdp, "%s\n", __func__);
        hp = sdp->host;
        if (hp) {
-               sdbg_host = *(struct sdebug_host_info **)shost_priv(hp);
+               sdbg_host = shost_to_sdebug_host(hp);
                if (sdbg_host) {
                        list_for_each_entry(devip,
                                            &sdbg_host->dev_info_list,
@@ -7165,7 +7164,7 @@ static void sdebug_release_adapter(struct device *dev)
 {
        struct sdebug_host_info *sdbg_host;
 
-       sdbg_host = to_sdebug_host(dev);
+       sdbg_host = dev_to_sdebug_host(dev);
        kfree(sdbg_host);
 }
 
@@ -7812,14 +7811,14 @@ static int sdebug_driver_probe(struct device *dev)
        struct Scsi_Host *hpnt;
        int hprot;
 
-       sdbg_host = to_sdebug_host(dev);
+       sdbg_host = dev_to_sdebug_host(dev);
 
        sdebug_driver_template.can_queue = sdebug_max_queue;
        sdebug_driver_template.cmd_per_lun = sdebug_max_queue;
        if (!sdebug_clustering)
                sdebug_driver_template.dma_boundary = PAGE_SIZE - 1;
 
-       hpnt = scsi_host_alloc(&sdebug_driver_template, sizeof(sdbg_host));
+       hpnt = scsi_host_alloc(&sdebug_driver_template, 0);
        if (NULL == hpnt) {
                pr_err("scsi_host_alloc failed\n");
                error = -ENODEV;
@@ -7862,7 +7861,6 @@ static int sdebug_driver_probe(struct device *dev)
                hpnt->nr_maps = 3;
 
        sdbg_host->shost = hpnt;
-       *((struct sdebug_host_info **)hpnt->hostdata) = sdbg_host;
        if ((hpnt->this_id >= 0) && (sdebug_num_tgts > hpnt->this_id))
                hpnt->max_id = sdebug_num_tgts + 1;
        else
@@ -7936,7 +7934,7 @@ static void sdebug_driver_remove(struct device *dev)
        struct sdebug_host_info *sdbg_host;
        struct sdebug_dev_info *sdbg_devinfo, *tmp;
 
-       sdbg_host = to_sdebug_host(dev);
+       sdbg_host = dev_to_sdebug_host(dev);
 
        scsi_remove_host(sdbg_host->shost);