scsi: Rework the code for caching Vital Product Data (VPD)

Introduce the scsi_get_vpd_buf() and scsi_update_vpd_page()
functions. The only functional change in this patch is that if updating
page 0x80 fails that it is attempted to update page 0x83.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Shane M 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 3d38c6d463b810f19fe2cbdd3dc69801465cd05a..f3f4926a3e77ebb0f717321a3b92c7d80995d7f2 100644 (file)
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -411,6 +411,63 @@ int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
 }
 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)
+{
+       unsigned char *vpd_buf;
+       int vpd_len = SCSI_VPD_PG_LEN, result;
+
+retry_pg:
+       vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
+       if (!vpd_buf)
+               return NULL;
+
+       result = scsi_vpd_inquiry(sdev, vpd_buf, page, vpd_len);
+       if (result < 0) {
+               kfree(vpd_buf);
+               return NULL;
+       }
+       if (result > vpd_len) {
+               vpd_len = result;
+               kfree(vpd_buf);
+               goto retry_pg;
+       }
+
+       *len = result;
+
+       return vpd_buf;
+}
+
+static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
+                                unsigned char __rcu **sdev_vpd_buf,
+                                int *sdev_vpd_len)
+{
+       unsigned char *vpd_buf;
+       int len;
+
+       vpd_buf = scsi_get_vpd_buf(sdev, page, &len);
+       if (!vpd_buf)
+               return;
+
+       mutex_lock(&sdev->inquiry_mutex);
+       rcu_swap_protected(*sdev_vpd_buf, vpd_buf,
+                          lockdep_is_held(&sdev->inquiry_mutex));
+       *sdev_vpd_len = len;
+       mutex_unlock(&sdev->inquiry_mutex);
+
+       synchronize_rcu();
+
+       kfree(vpd_buf);
+}
+
 /**
  * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
  * @sdev: The device to ask
@@ -422,95 +479,26 @@ EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
  */
 void scsi_attach_vpd(struct scsi_device *sdev)
 {
-       int result, i;
-       int vpd_len = SCSI_VPD_PG_LEN;
-       int pg80_supported = 0;
-       int pg83_supported = 0;
-       unsigned char __rcu *vpd_buf, *orig_vpd_buf = NULL;
+       int i, vpd_len;
+       unsigned char *vpd_buf;
 
        if (!scsi_device_supports_vpd(sdev))
                return;
 
-retry_pg0:
-       vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
-       if (!vpd_buf)
-               return;
-
        /* Ask for all the pages supported by this device */
-       result = scsi_vpd_inquiry(sdev, vpd_buf, 0, vpd_len);
-       if (result < 0) {
-               kfree(vpd_buf);
+       vpd_buf = scsi_get_vpd_buf(sdev, 0, &vpd_len);
+       if (!vpd_buf)
                return;
-       }
-       if (result > vpd_len) {
-               vpd_len = result;
-               kfree(vpd_buf);
-               goto retry_pg0;
-       }
 
-       for (i = 4; i < result; i++) {
+       for (i = 4; i < vpd_len; i++) {
                if (vpd_buf[i] == 0x80)
-                       pg80_supported = 1;
+                       scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80,
+                                            &sdev->vpd_pg80_len);
                if (vpd_buf[i] == 0x83)
-                       pg83_supported = 1;
+                       scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83,
+                                            &sdev->vpd_pg83_len);
        }
        kfree(vpd_buf);
-       vpd_len = SCSI_VPD_PG_LEN;
-
-       if (pg80_supported) {
-retry_pg80:
-               vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
-               if (!vpd_buf)
-                       return;
-
-               result = scsi_vpd_inquiry(sdev, vpd_buf, 0x80, vpd_len);
-               if (result < 0) {
-                       kfree(vpd_buf);
-                       return;
-               }
-               if (result > vpd_len) {
-                       vpd_len = result;
-                       kfree(vpd_buf);
-                       goto retry_pg80;
-               }
-               mutex_lock(&sdev->inquiry_mutex);
-               orig_vpd_buf = sdev->vpd_pg80;
-               sdev->vpd_pg80_len = result;
-               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;
-       }
-
-       if (pg83_supported) {
-retry_pg83:
-               vpd_buf = kmalloc(vpd_len, GFP_KERNEL);
-               if (!vpd_buf)
-                       return;
-
-               result = scsi_vpd_inquiry(sdev, vpd_buf, 0x83, vpd_len);
-               if (result < 0) {
-                       kfree(vpd_buf);
-                       return;
-               }
-               if (result > vpd_len) {
-                       vpd_len = result;
-                       kfree(vpd_buf);
-                       goto retry_pg83;
-               }
-               mutex_lock(&sdev->inquiry_mutex);
-               orig_vpd_buf = sdev->vpd_pg83;
-               sdev->vpd_pg83_len = result;
-               rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
-               mutex_unlock(&sdev->inquiry_mutex);
-               synchronize_rcu();
-               if (orig_vpd_buf)
-                       kfree(orig_vpd_buf);
-       }
 }
 
 /**