RDMA/uverbs: Refactor command header processing

Move all command header processing into separate function
and perform those checks before acquiring SRCU read lock.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 20797a1..906fcce 100644 (file)
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -660,6 +660,29 @@ static bool verify_command_idx(u32 command, bool extended)
               uverbs_cmd_table[command];
 }
 
+static ssize_t process_hdr(struct ib_uverbs_cmd_hdr *hdr,
+                          __u32 *command, bool *extended)
+{
+       __u32 flags;
+
+       if (hdr->command & ~(__u32)(IB_USER_VERBS_CMD_FLAGS_MASK |
+                                  IB_USER_VERBS_CMD_COMMAND_MASK))
+               return -EINVAL;
+
+       *command = hdr->command & IB_USER_VERBS_CMD_COMMAND_MASK;
+       flags = (hdr->command &
+                IB_USER_VERBS_CMD_FLAGS_MASK) >> IB_USER_VERBS_CMD_FLAGS_SHIFT;
+
+       *extended = flags & IB_USER_VERBS_CMD_FLAG_EXTENDED;
+       if (flags & ~IB_USER_VERBS_CMD_FLAG_EXTENDED)
+               return -EINVAL;
+
+       if (!verify_command_idx(*command, *extended))
+               return -EOPNOTSUPP;
+
+       return 0;
+}
+
 static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
                             size_t count, loff_t *pos)
 {
@@ -667,9 +690,8 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
        struct ib_uverbs_ex_cmd_hdr ex_hdr;
        struct ib_device *ib_dev;
        struct ib_uverbs_cmd_hdr hdr;
-       bool extended_command;
+       bool extended;
        __u32 command;
-       __u32 flags;
        int srcu_key;
        ssize_t ret;
 
@@ -685,6 +707,13 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
        if (copy_from_user(&hdr, buf, sizeof(hdr)))
                return -EFAULT;
 
+       ret = process_hdr(&hdr, &command, &extended);
+       if (ret)
+               return ret;
+
+       if (extended && count < (sizeof(hdr) + sizeof(ex_hdr)))
+               return -EINVAL;
+
        srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
        ib_dev = srcu_dereference(file->device->ib_dev,
                                  &file->device->disassociate_srcu);
@@ -693,33 +722,6 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
                goto out;
        }
 
-       if (hdr.command & ~(__u32)(IB_USER_VERBS_CMD_FLAGS_MASK |
-                                  IB_USER_VERBS_CMD_COMMAND_MASK)) {
-               ret = -EINVAL;
-               goto out;
-       }
-
-       command = hdr.command & IB_USER_VERBS_CMD_COMMAND_MASK;
-       flags = (hdr.command &
-                IB_USER_VERBS_CMD_FLAGS_MASK) >> IB_USER_VERBS_CMD_FLAGS_SHIFT;
-
-       extended_command = flags & IB_USER_VERBS_CMD_FLAG_EXTENDED;
-       if (flags & ~IB_USER_VERBS_CMD_FLAG_EXTENDED) {
-               ret = -EINVAL;
-               goto out;
-       }
-
-       if (extended_command &&
-           count < (sizeof(hdr) + sizeof(ex_hdr))) {
-               ret = -EINVAL;
-               goto out;
-       }
-
-       if (!verify_command_idx(command, extended_command)) {
-               ret = -EOPNOTSUPP;
-               goto out;
-       }
-
        if (!verify_command_mask(ib_dev, command)) {
                ret = -EOPNOTSUPP;
                goto out;
@@ -731,7 +733,7 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
                goto out;
        }
 
-       if (!flags) {
+       if (!extended) {
                if (hdr.in_words * 4 != count) {
                        ret = -EINVAL;
                        goto out;