scsi: rescan VPD attributes

The VPD page information might change, so we need to be able to update
it. This patch implements a VPD page rescan whenever the 'rescan' sysfs
attribute is triggered.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index d07fb653f5dc3348c41bbc68597489d2c4b25180..b1bf42b93fccb23249e4341e3ce56f6b8c84c5d5 100644 (file)
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -782,7 +782,7 @@ void scsi_attach_vpd(struct scsi_device *sdev)
        int vpd_len = SCSI_VPD_PG_LEN;
        int pg80_supported = 0;
        int pg83_supported = 0;
-       unsigned char *vpd_buf;
+       unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;
 
        if (sdev->skip_vpd_pages)
                return;
@@ -828,8 +828,16 @@ retry_pg80:
                        kfree(vpd_buf);
                        goto retry_pg80;
                }
+               mutex_lock(&sdev->inquiry_mutex);
+               orig_vpd_buf = sdev->vpd_pg80;
                sdev->vpd_pg80_len = result;
-               sdev->vpd_pg80 = vpd_buf;
+               rcu_assign_pointer(sdev->vpd_pg80, vpd_buf);
+               mutex_unlock(&sdev->inquiry_mutex);
+               synchronize_rcu();
+               if (orig_vpd_buf) {
+                       kfree(orig_vpd_buf);
+                       orig_vpd_buf = NULL;
+               }
                vpd_len = SCSI_VPD_PG_LEN;
        }
 
@@ -849,8 +857,14 @@ retry_pg83:
                        kfree(vpd_buf);
                        goto retry_pg83;
                }
+               mutex_lock(&sdev->inquiry_mutex);
+               orig_vpd_buf = sdev->vpd_pg83;
                sdev->vpd_pg83_len = result;
-               sdev->vpd_pg83 = vpd_buf;
+               rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
+               mutex_unlock(&sdev->inquiry_mutex);
+               synchronize_rcu();
+               if (orig_vpd_buf)
+                       kfree(orig_vpd_buf);
        }
 }
 

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 83245391e956bc6f351a668473debeba6121b71b..a1c195d71fd1c8ee24d4c43ddaf0a8b1818882c5 100644 (file)
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -236,6 +236,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
        INIT_LIST_HEAD(&sdev->starved_entry);
        INIT_LIST_HEAD(&sdev->event_list);
        spin_lock_init(&sdev->list_lock);
+       mutex_init(&sdev->inquiry_mutex);
        INIT_WORK(&sdev->event_work, scsi_evt_thread);
        INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
 
@@ -1516,6 +1517,9 @@ EXPORT_SYMBOL(scsi_add_device);
 void scsi_rescan_device(struct device *dev)
 {
        device_lock(dev);
+
+       scsi_attach_vpd(to_scsi_device(dev));
+
        if (dev->driver && try_module_get(dev->driver->owner)) {
                struct scsi_driver *drv = to_scsi_driver(dev->driver);
 

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 8d2312239ae0cda01238ae549f0ae8007de233ea..158f1b553acffd0fc65e598b8b00b492caf3f494 100644 (file)
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -760,11 +760,15 @@ show_vpd_##_page(struct file *filp, struct kobject *kobj, \
 {                                                                      \
        struct device *dev = container_of(kobj, struct device, kobj);   \
        struct scsi_device *sdev = to_scsi_device(dev);                 \
+       int ret;                                                        \
        if (!sdev->vpd_##_page)                                         \
                return -EINVAL;                                         \
-       return memory_read_from_buffer(buf, count, &off,                \
-                                      sdev->vpd_##_page,               \
+       rcu_read_lock();                                                \
+       ret = memory_read_from_buffer(buf, count, &off,                 \
+                                     rcu_dereference(sdev->vpd_##_page), \
                                       sdev->vpd_##_page##_len);        \
+       rcu_read_unlock();                                              \
+       return ret;                                             \
 }                                                                      \
 static struct bin_attribute dev_attr_vpd_##_page = {           \
        .attr = {.name = __stringify(vpd_##_page), .mode = S_IRUGO },   \

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index dcb0d76d7312847d37809df1f5763206567d5daf..e234da78ce6e50332a79a44b7cbe781808ecb393 100644 (file)
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -554,17 +554,22 @@ static void ses_match_to_enclosure(struct enclosure_device *edev,
                                   struct scsi_device *sdev)
 {
        unsigned char *desc;
+       unsigned char __rcu *vpd_pg83;
        struct efd efd = {
                .addr = 0,
        };
 
        ses_enclosure_data_process(edev, to_scsi_device(edev->edev.parent), 0);
 
-       if (!sdev->vpd_pg83_len)
+       rcu_read_lock();
+       vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
+       if (!vpd_pg83) {
+               rcu_read_unlock();
                return;
+       }
 
-       desc = sdev->vpd_pg83 + 4;
-       while (desc < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
+       desc = vpd_pg83 + 4;
+       while (desc < vpd_pg83 + sdev->vpd_pg83_len) {
                enum scsi_protocol proto = desc[0] >> 4;
                u8 code_set = desc[0] & 0x0f;
                u8 piv = desc[1] & 0x80;
@@ -578,6 +583,7 @@ static void ses_match_to_enclosure(struct enclosure_device *edev,
 
                desc += len + 4;
        }
+       rcu_read_unlock();
        if (efd.addr) {
                efd.dev = &sdev->sdev_gendev;
 

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index fe89d7cd67b9d3cfdcacddc6e17bb9366de38c0f..bde4077f2864a182c071519f6d450035767e79a2 100644 (file)
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -109,6 +109,7 @@ struct scsi_device {
        char type;
        char scsi_level;
        char inq_periph_qual;   /* PQ from INQUIRY data */      
+       struct mutex inquiry_mutex;
        unsigned char inquiry_len;      /* valid bytes in 'inquiry' */
        unsigned char * inquiry;        /* INQUIRY response data */
        const char * vendor;            /* [back_compat] point into 'inquiry' ... */
@@ -117,9 +118,9 @@ struct scsi_device {
 
 #define SCSI_VPD_PG_LEN                255
        int vpd_pg83_len;
-       unsigned char *vpd_pg83;
+       unsigned char __rcu *vpd_pg83;
        int vpd_pg80_len;
-       unsigned char *vpd_pg80;
+       unsigned char __rcu *vpd_pg80;
        unsigned char current_tag;      /* current tag */
        struct scsi_target      *sdev_target;   /* used only for single_lun */