Merge branch 'release' of git://lm-sensors.org/kernel/mhoffman/hwmon-2.6

[linux-2.6-omap-h63xx.git] / drivers / infiniband / core / ucma.c

diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 90d675ad9ec8af51acaea573a58ea91f8ebc40de..15937eb38aae42f440a71ae6f8240ffc16c057bb 100644 (file)
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -31,6 +31,7 @@
  */
 
 #include <linux/completion.h>
+#include <linux/file.h>
 #include <linux/mutex.h>
 #include <linux/poll.h>
 #include <linux/idr.h>
@@ -991,6 +992,96 @@ out:
        return ret;
 }
 
+static void ucma_lock_files(struct ucma_file *file1, struct ucma_file *file2)
+{
+       /* Acquire mutex's based on pointer comparison to prevent deadlock. */
+       if (file1 < file2) {
+               mutex_lock(&file1->mut);
+               mutex_lock(&file2->mut);
+       } else {
+               mutex_lock(&file2->mut);
+               mutex_lock(&file1->mut);
+       }
+}
+
+static void ucma_unlock_files(struct ucma_file *file1, struct ucma_file *file2)
+{
+       if (file1 < file2) {
+               mutex_unlock(&file2->mut);
+               mutex_unlock(&file1->mut);
+       } else {
+               mutex_unlock(&file1->mut);
+               mutex_unlock(&file2->mut);
+       }
+}
+
+static void ucma_move_events(struct ucma_context *ctx, struct ucma_file *file)
+{
+       struct ucma_event *uevent, *tmp;
+
+       list_for_each_entry_safe(uevent, tmp, &ctx->file->event_list, list)
+               if (uevent->ctx == ctx)
+                       list_move_tail(&uevent->list, &file->event_list);
+}
+
+static ssize_t ucma_migrate_id(struct ucma_file *new_file,
+                              const char __user *inbuf,
+                              int in_len, int out_len)
+{
+       struct rdma_ucm_migrate_id cmd;
+       struct rdma_ucm_migrate_resp resp;
+       struct ucma_context *ctx;
+       struct file *filp;
+       struct ucma_file *cur_file;
+       int ret = 0;
+
+       if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
+               return -EFAULT;
+
+       /* Get current fd to protect against it being closed */
+       filp = fget(cmd.fd);
+       if (!filp)
+               return -ENOENT;
+
+       /* Validate current fd and prevent destruction of id. */
+       ctx = ucma_get_ctx(filp->private_data, cmd.id);
+       if (IS_ERR(ctx)) {
+               ret = PTR_ERR(ctx);
+               goto file_put;
+       }
+
+       cur_file = ctx->file;
+       if (cur_file == new_file) {
+               resp.events_reported = ctx->events_reported;
+               goto response;
+       }
+
+       /*
+        * Migrate events between fd's, maintaining order, and avoiding new
+        * events being added before existing events.
+        */
+       ucma_lock_files(cur_file, new_file);
+       mutex_lock(&mut);
+
+       list_move_tail(&ctx->list, &new_file->ctx_list);
+       ucma_move_events(ctx, new_file);
+       ctx->file = new_file;
+       resp.events_reported = ctx->events_reported;
+
+       mutex_unlock(&mut);
+       ucma_unlock_files(cur_file, new_file);
+
+response:
+       if (copy_to_user((void __user *)(unsigned long)cmd.response,
+                        &resp, sizeof(resp)))
+               ret = -EFAULT;
+
+       ucma_put_ctx(ctx);
+file_put:
+       fput(filp);
+       return ret;
+}
+
 static ssize_t (*ucma_cmd_table[])(struct ucma_file *file,
                                   const char __user *inbuf,
                                   int in_len, int out_len) = {
@@ -1012,6 +1103,7 @@ static ssize_t (*ucma_cmd_table[])(struct ucma_file *file,
        [RDMA_USER_CM_CMD_NOTIFY]       = ucma_notify,
        [RDMA_USER_CM_CMD_JOIN_MCAST]   = ucma_join_multicast,
        [RDMA_USER_CM_CMD_LEAVE_MCAST]  = ucma_leave_multicast,
+       [RDMA_USER_CM_CMD_MIGRATE_ID]   = ucma_migrate_id
 };
 
 static ssize_t ucma_write(struct file *filp, const char __user *buf,