dm ioctl: Simplify parameter buffer management code

Merge the two DM_PARAMS_[KV]MALLOC flags into a single flag.

Doing so avoids the crashes seen with previous attempts to consolidate
buffer management to use kvfree() without first flagging that memory had
actually been allocated.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index b59e345..96df89a 100644 (file)
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1670,8 +1670,7 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
        return r;
 }
 
-#define DM_PARAMS_KMALLOC      0x0001  /* Params alloced with kmalloc */
-#define DM_PARAMS_VMALLOC      0x0002  /* Params alloced with vmalloc */
+#define DM_PARAMS_MALLOC       0x0001  /* Params allocated with kvmalloc() */
 #define DM_WIPE_BUFFER         0x0010  /* Wipe input buffer before returning from ioctl */
 
 static void free_params(struct dm_ioctl *param, size_t param_size, int param_flags)
@@ -1679,10 +1678,8 @@ static void free_params(struct dm_ioctl *param, size_t param_size, int param_fla
        if (param_flags & DM_WIPE_BUFFER)
                memset(param, 0, param_size);
 
-       if (param_flags & DM_PARAMS_KMALLOC)
-               kfree(param);
-       if (param_flags & DM_PARAMS_VMALLOC)
-               vfree(param);
+       if (param_flags & DM_PARAMS_MALLOC)
+               kvfree(param);
 }
 
 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kernel,
@@ -1714,19 +1711,14 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
         * Use kmalloc() rather than vmalloc() when we can.
         */
        dmi = NULL;
-       if (param_kernel->data_size <= KMALLOC_MAX_SIZE) {
+       if (param_kernel->data_size <= KMALLOC_MAX_SIZE)
                dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
-               if (dmi)
-                       *param_flags |= DM_PARAMS_KMALLOC;
-       }
 
        if (!dmi) {
                unsigned noio_flag;
                noio_flag = memalloc_noio_save();
                dmi = __vmalloc(param_kernel->data_size, GFP_NOIO | __GFP_HIGH | __GFP_HIGHMEM, PAGE_KERNEL);
                memalloc_noio_restore(noio_flag);
-               if (dmi)
-                       *param_flags |= DM_PARAMS_VMALLOC;
        }
 
        if (!dmi) {
@@ -1735,6 +1727,8 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern
                return -ENOMEM;
        }
 
+       *param_flags |= DM_PARAMS_MALLOC;
+
        if (copy_from_user(dmi, user, param_kernel->data_size))
                goto bad;