Introduce struct scsi_vpd for the VPD page length, data and the
RCU head that will be used to free the VPD data. Use kfree_rcu()
instead of kfree() to free VPD data. Only annotate pointers that
are shared across threads with __rcu. Use rcu_dereference() when
dereferencing an RCU pointer. This patch suppresses about twenty
sparse complaints about the vpd_pg8[03] pointers.
Fixes: commit 09e2b0b14690 ("scsi: rescan VPD attributes")
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: Shane Seymour <shane.seymour@xxxxxxx>
---
drivers/scsi/scsi.c | 48 +++++++++++++++++++++-------------------------
drivers/scsi/scsi_lib.c | 16 ++++++++--------
drivers/scsi/scsi_sysfs.c | 26 +++++++++++++++++++------
include/scsi/scsi_device.h | 18 +++++++++++++----
4 files changed, 64 insertions(+), 44 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 775f609f89e2..1cf3aef0de8a 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -415,22 +415,20 @@ EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
* scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
* @sdev: The device to ask
* @page: Which Vital Product Data to return
- * @len: Upon success, the VPD length will be stored in *@len.
*
* Returns %NULL upon failure.
*/
-static unsigned char *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page,
- int *len)
+static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
{
- unsigned char *vpd_buf;
+ struct scsi_vpd *vpd_buf;
int vpd_len = SCSI_VPD_PG_LEN, result;
retry_pg:
- vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
+ vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
if (!vpd_buf)
return NULL;
- result = scsi_vpd_inquiry(sdev, vpd_buf, page, vpd_len);
+ result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
if (result < 0) {
kfree(vpd_buf);
return NULL;
@@ -441,7 +439,7 @@ static unsigned char *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page,
goto retry_pg;
}
- *len = result;
+ vpd_buf->len = result;
return vpd_buf;
}
@@ -458,52 +456,50 @@ static unsigned char *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page,
void scsi_attach_vpd(struct scsi_device *sdev)
{
int i;
- int vpd_len;
int pg80_supported = 0;
int pg83_supported = 0;
- unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;
+ struct scsi_vpd *vpd_buf, *orig_vpd_buf;
if (!scsi_device_supports_vpd(sdev))
return;
/* Ask for all the pages supported by this device */
- vpd_buf = scsi_get_vpd_buf(sdev, 0, &vpd_len);
+ vpd_buf = scsi_get_vpd_buf(sdev, 0);
if (!vpd_buf)
return;
- for (i = 4; i < vpd_len; i++) {
- if (vpd_buf[i] == 0x80)
+ for (i = 4; i < vpd_buf->len; i++) {
+ if (vpd_buf->data[i] == 0x80)
pg80_supported = 1;
- if (vpd_buf[i] == 0x83)
+ if (vpd_buf->data[i] == 0x83)
pg83_supported = 1;
}
kfree(vpd_buf);
if (pg80_supported) {
- vpd_buf = scsi_get_vpd_buf(sdev, 0x80, &vpd_len);
+ vpd_buf = scsi_get_vpd_buf(sdev, 0x80);
mutex_lock(&sdev->inquiry_mutex);
- orig_vpd_buf = sdev->vpd_pg80;
- sdev->vpd_pg80_len = vpd_len;
+ orig_vpd_buf = rcu_dereference_protected(sdev->vpd_pg80,
+ lockdep_is_held(&sdev->inquiry_mutex));
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;
- }
+
+ if (orig_vpd_buf)
+ kfree_rcu(orig_vpd_buf, rcu);
}
if (pg83_supported) {
- vpd_buf = scsi_get_vpd_buf(sdev, 0x83, &vpd_len);
+ vpd_buf = scsi_get_vpd_buf(sdev, 0x83);
+
mutex_lock(&sdev->inquiry_mutex);
- orig_vpd_buf = sdev->vpd_pg83;
- sdev->vpd_pg83_len = vpd_len;
+ orig_vpd_buf = rcu_dereference_protected(sdev->vpd_pg83,
+ lockdep_is_held(&sdev->inquiry_mutex));
rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
mutex_unlock(&sdev->inquiry_mutex);
- synchronize_rcu();
+
if (orig_vpd_buf)
- kfree(orig_vpd_buf);
+ kfree_rcu(orig_vpd_buf, rcu);
}
}
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 813d2456ae93..3d6e50087600 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -3276,8 +3276,8 @@ int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
{
u8 cur_id_type = 0xff;
u8 cur_id_size = 0;
- unsigned char *d, *cur_id_str;
- unsigned char __rcu *vpd_pg83;
+ const unsigned char *d, *cur_id_str;
+ const struct scsi_vpd *vpd_pg83;
int id_size = -EINVAL;
rcu_read_lock();
@@ -3308,8 +3308,8 @@ int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
}
memset(id, 0, id_len);
- d = vpd_pg83 + 4;
- while (d < vpd_pg83 + sdev->vpd_pg83_len) {
+ d = vpd_pg83->data + 4;
+ while (d < vpd_pg83->data + vpd_pg83->len) {
/* Skip designators not referring to the LUN */
if ((d[1] & 0x30) != 0x00)
goto next_desig;
@@ -3425,8 +3425,8 @@ EXPORT_SYMBOL(scsi_vpd_lun_id);
*/
int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
{
- unsigned char *d;
- unsigned char __rcu *vpd_pg83;
+ const unsigned char *d;
+ const struct scsi_vpd *vpd_pg83;
int group_id = -EAGAIN, rel_port = -1;
rcu_read_lock();
@@ -3436,8 +3436,8 @@ int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
return -ENXIO;
}
- d = sdev->vpd_pg83 + 4;
- while (d < sdev->vpd_pg83 + sdev->vpd_pg83_len) {
+ d = vpd_pg83->data + 4;
+ while (d < vpd_pg83->data + vpd_pg83->len) {
switch (d[1] & 0xf) {
case 0x4:
/* Relative target port */
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 5ed473a87589..8a75e0f10eeb 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -428,6 +428,7 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
struct scsi_device *sdev;
struct device *parent;
struct list_head *this, *tmp;
+ struct scsi_vpd *vpd_pg80, *vpd_pg83;
unsigned long flags;
sdev = container_of(work, struct scsi_device, ew.work);
@@ -456,8 +457,19 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
/* NULL queue means the device can't be used */
sdev->request_queue = NULL;
- kfree(sdev->vpd_pg83);
- kfree(sdev->vpd_pg80);
+ mutex_lock(&sdev->inquiry_mutex);
+ vpd_pg80 = rcu_dereference_protected(sdev->vpd_pg80,
+ lockdep_is_held(&sdev->inquiry_mutex));
+ rcu_assign_pointer(sdev->vpd_pg80, NULL);
+ vpd_pg83 = rcu_dereference_protected(sdev->vpd_pg83,
+ lockdep_is_held(&sdev->inquiry_mutex));
+ rcu_assign_pointer(sdev->vpd_pg83, NULL);
+ mutex_unlock(&sdev->inquiry_mutex);
+
+ if (vpd_pg83)
+ kfree_rcu(vpd_pg83, rcu);
+ if (vpd_pg80)
+ kfree_rcu(vpd_pg80, rcu);
kfree(sdev->inquiry);
kfree(sdev);
@@ -795,15 +807,17 @@ 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); \
+ struct scsi_vpd *vpd_page; \
int ret; \
+ \
if (!sdev->vpd_##_page) \
return -EINVAL; \
rcu_read_lock(); \
- ret = memory_read_from_buffer(buf, count, &off, \
- rcu_dereference(sdev->vpd_##_page), \
- sdev->vpd_##_page##_len); \
+ vpd_page = rcu_dereference(sdev->vpd_##_page); \
+ ret = memory_read_from_buffer(buf, count, &off, vpd_page->data, \
+ vpd_page->len); \
rcu_read_unlock(); \
- return ret; \
+ return ret; \
} \
static struct bin_attribute dev_attr_vpd_##_page = { \
.attr = {.name = __stringify(vpd_##_page), .mode = S_IRUGO }, \
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index f054f3f43c75..82e93ee94708 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -80,6 +80,18 @@ struct scsi_event {
*/
};
+/**
+ * struct scsi_vpd - SCSI Vital Product Data
+ * @rcu: For kfree_rcu().
+ * @len: Length in bytes of @data.
+ * @data: VPD data as defined in various T10 SCSI standard documents.
+ */
+struct scsi_vpd {
+ struct rcu_head rcu;
+ int len;
+ unsigned char data[];
+};
+
struct scsi_device {
struct Scsi_Host *host;
struct request_queue *request_queue;
@@ -122,10 +134,8 @@ struct scsi_device {
const char * rev; /* ... "nullnullnullnull" before scan */
#define SCSI_VPD_PG_LEN 255
- int vpd_pg83_len;
- unsigned char __rcu *vpd_pg83;
- int vpd_pg80_len;
- unsigned char __rcu *vpd_pg80;
+ struct scsi_vpd __rcu *vpd_pg83;
+ struct scsi_vpd __rcu *vpd_pg80;
unsigned char current_tag; /* current tag */
struct scsi_target *sdev_target; /* used only for single_lun */
--
2.14.1
