On Mon, 2015-11-09 at 13:24 +0100, Hannes Reinecke wrote:
> 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@xxxxxxx>
> ---
> drivers/scsi/scsi.c | 20 +++++++++++++++++---
> drivers/scsi/scsi_scan.c | 4 ++++
> drivers/scsi/scsi_sysfs.c | 8 ++++++--
> drivers/scsi/ses.c | 12 +++++++++---
> include/scsi/scsi_device.h | 5 +++--
> 5 files changed, 39 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index 207d6a7..2e4ef56 100644
> --- a/drivers/scsi/scsi.c
> +++ b/drivers/scsi/scsi.c
> @@ -803,7 +803,7 @@ 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;
> @@ -849,8 +849,16 @@ 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;
> }
>
> @@ -870,8 +878,14 @@ 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 3b3dfef..7e0820f 100644
> --- 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);
>
> @@ -1517,6 +1518,9 @@ 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 fdcf0ab..f021423 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -758,11 +758,15 @@ 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 dcb0d76..e234da7 100644
> --- 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 fe89d7c..bde4077 100644
> --- 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
> */
>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
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