[S390] vmur: diag14 only works with buffers below 2GB

If memory buffers above 2GB are used, diagnose 14 raises a specification
exception. This fix ensures that buffer allocation is done below the 2GB
boundary.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 70 insertions, 36 deletions

diff --git a/drivers/s390/char/vmur.c b/drivers/s390/char/vmur.c
index a9d58629e795..04b19bdc09da 100644
--- a/drivers/s390/char/vmur.c
+++ b/drivers/s390/char/vmur.c
@@ -472,7 +472,7 @@ static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
                 return rc;
 
         len = min((size_t) PAGE_SIZE, count);
-        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+        buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
         if (!buf)
                 return -ENOMEM;
 
@@ -499,7 +499,7 @@ static ssize_t diag14_read(struct file *file, char __user *ubuf, size_t count,
         *offs += copied;
         rc = copied;
 fail:
-        kfree(buf);
+        free_page((unsigned long) buf);
         return rc;
 }
 
@@ -542,63 +542,97 @@ static int diag_read_next_file_info(struct file_control_block *buf, int spid)
         }
 }
 
-static int verify_device(struct urdev *urd)
+static int verify_uri_device(struct urdev *urd)
 {
-        struct file_control_block fcb;
+        struct file_control_block *fcb;
         char *buf;
         int rc;
 
+        fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
+        if (!fcb)
+                return -ENOMEM;
+
+        /* check for empty reader device (beginning of chain) */
+        rc = diag_read_next_file_info(fcb, 0);
+        if (rc)
+                goto fail_free_fcb;
+
+        /* if file is in hold status, we do not read it */
+        if (fcb->file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD)) {
+                rc = -EPERM;
+                goto fail_free_fcb;
+        }
+
+        /* open file on virtual reader  */
+        buf = (char *) __get_free_page(GFP_KERNEL | GFP_DMA);
+        if (!buf) {
+                rc = -ENOMEM;
+                goto fail_free_fcb;
+        }
+        rc = diag_read_file(urd->dev_id.devno, buf);
+        if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
+                goto fail_free_buf;
+
+        /* check if the file on top of the queue is open now */
+        rc = diag_read_next_file_info(fcb, 0);
+        if (rc)
+                goto fail_free_buf;
+        if (!(fcb->file_stat & FLG_IN_USE)) {
+                rc = -EMFILE;
+                goto fail_free_buf;
+        }
+        rc = 0;
+
+fail_free_buf:
+        free_page((unsigned long) buf);
+fail_free_fcb:
+        kfree(fcb);
+        return rc;
+}
+
+static int verify_device(struct urdev *urd)
+{
         switch (urd->class) {
         case DEV_CLASS_UR_O:
                 return 0; /* no check needed here */
         case DEV_CLASS_UR_I:
-                /* check for empty reader device (beginning of chain) */
-                rc = diag_read_next_file_info(&fcb, 0);
-                if (rc)
-                        return rc;
-                /* if file is in hold status, we do not read it */
-                if (fcb.file_stat & (FLG_SYSTEM_HOLD | FLG_USER_HOLD))
-                        return -EPERM;
-                /* open file on virtual reader  */
-                buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-                if (!buf)
-                        return -ENOMEM;
-                rc = diag_read_file(urd->dev_id.devno, buf);
-                kfree(buf);
-                if ((rc != 0) && (rc != -ENODATA)) /* EOF does not hurt */
-                        return rc;
-                /* check if the file on top of the queue is open now */
-                rc = diag_read_next_file_info(&fcb, 0);
-                if (rc)
-                        return rc;
-                if (!(fcb.file_stat & FLG_IN_USE))
-                        return -EMFILE;
-                return 0;
+                return verify_uri_device(urd);
         default:
                 return -ENOTSUPP;
         }
 }
 
-static int get_file_reclen(struct urdev *urd)
+static int get_uri_file_reclen(struct urdev *urd)
 {
-        struct file_control_block fcb;
+        struct file_control_block *fcb;
         int rc;
 
+        fcb = kmalloc(sizeof(*fcb), GFP_KERNEL | GFP_DMA);
+        if (!fcb)
+                return -ENOMEM;
+        rc = diag_read_next_file_info(fcb, 0);
+        if (rc)
+                goto fail_free;
+        if (fcb->file_stat & FLG_CP_DUMP)
+                rc = 0;
+        else
+                rc = fcb->rec_len;
+
+fail_free:
+        kfree(fcb);
+        return rc;
+}
+
+static int get_file_reclen(struct urdev *urd)
+{
         switch (urd->class) {
         case DEV_CLASS_UR_O:
                 return 0;
         case DEV_CLASS_UR_I:
-                rc = diag_read_next_file_info(&fcb, 0);
-                if (rc)
-                        return rc;
-                break;
+                return get_uri_file_reclen(urd);
         default:
                 return -ENOTSUPP;
         }
-        if (fcb.file_stat & FLG_CP_DUMP)
-                return 0;
-
-        return fcb.rec_len;
 }
 
 static int ur_open(struct inode *inode, struct file *file)