[dpdk-dev] [PATCH v5 1/4] vhost: eventfd_link: refactoring EVENTFD_COPY handler

[Pavel Boldin]

Ping.

On Fri, Aug 28, 2015 at 9:51 PM, Pavel Boldin <pboldin at mirantis.com> wrote:

> * Move ioctl `EVENTFD_COPY' code to a separate function
> * Remove extra #includes
> * Introduce function fget_from_files
> * Fix ioctl return values
>
> Signed-off-by: Pavel Boldin <pboldin at mirantis.com>
> ---
>  lib/librte_vhost/eventfd_link/eventfd_link.c | 188
> +++++++++++++++------------
>  1 file changed, 103 insertions(+), 85 deletions(-)
>
> diff --git a/lib/librte_vhost/eventfd_link/eventfd_link.c
> b/lib/librte_vhost/eventfd_link/eventfd_link.c
> index 62c45c8..5ba1068 100644
> --- a/lib/librte_vhost/eventfd_link/eventfd_link.c
> +++ b/lib/librte_vhost/eventfd_link/eventfd_link.c
> @@ -22,18 +22,11 @@
>   *   Intel Corporation
>   */
>
> -#include <linux/eventfd.h>
>  #include <linux/miscdevice.h>
>  #include <linux/module.h>
> -#include <linux/moduleparam.h>
> -#include <linux/rcupdate.h>
>  #include <linux/file.h>
> -#include <linux/slab.h>
> -#include <linux/fs.h>
> -#include <linux/mmu_context.h>
> -#include <linux/sched.h>
> -#include <asm/mmu_context.h>
>  #include <linux/fdtable.h>
> +#include <linux/syscalls.h>
>
>  #include "eventfd_link.h"
>
> @@ -65,9 +58,26 @@ put_files_struct(struct files_struct *files)
>                 BUG();
>  }
>
> +static struct file *
> +fget_from_files(struct files_struct *files, unsigned fd)
> +{
> +       struct file *file;
> +
> +       rcu_read_lock();
> +       file = fcheck_files(files, fd);
> +       if (file)
> +       {
> +               if (file->f_mode & FMODE_PATH
> +                       || !atomic_long_inc_not_zero(&file->f_count))
> +                   file = NULL;
> +       }
> +       rcu_read_unlock();
> +
> +       return file;
> +}
>
>  static long
> -eventfd_link_ioctl(struct file *f, unsigned int ioctl, unsigned long arg)
> +eventfd_link_ioctl_copy(unsigned long arg)
>  {
>         void __user *argp = (void __user *) arg;
>         struct task_struct *task_target = NULL;
> @@ -75,91 +85,99 @@ eventfd_link_ioctl(struct file *f, unsigned int ioctl,
> unsigned long arg)
>         struct files_struct *files;
>         struct fdtable *fdt;
>         struct eventfd_copy eventfd_copy;
> +       long ret = -EFAULT;
>
> -       switch (ioctl) {
> -       case EVENTFD_COPY:
> -               if (copy_from_user(&eventfd_copy, argp,
> -                       sizeof(struct eventfd_copy)))
> -                       return -EFAULT;
> -
> -               /*
> -                * Find the task struct for the target pid
> -                */
> -               task_target =
> -                       pid_task(find_vpid(eventfd_copy.target_pid),
> PIDTYPE_PID);
> -               if (task_target == NULL) {
> -                       pr_debug("Failed to get mem ctx for target pid\n");
> -                       return -EFAULT;
> -               }
> -
> -               files = get_files_struct(current);
> -               if (files == NULL) {
> -                       pr_debug("Failed to get files struct\n");
> -                       return -EFAULT;
> -               }
> -
> -               rcu_read_lock();
> -               file = fcheck_files(files, eventfd_copy.source_fd);
> -               if (file) {
> -                       if (file->f_mode & FMODE_PATH ||
> -                               !atomic_long_inc_not_zero(&file->f_count))
> -                               file = NULL;
> -               }
> -               rcu_read_unlock();
> -               put_files_struct(files);
> +       if (copy_from_user(&eventfd_copy, argp, sizeof(struct
> eventfd_copy)))
> +               goto out;
> +
> +       /*
> +        * Find the task struct for the target pid
> +        */
> +       ret = -ESRCH;
> +
> +       task_target =
> +               get_pid_task(find_vpid(eventfd_copy.target_pid),
> PIDTYPE_PID);
> +       if (task_target == NULL) {
> +               pr_info("Unable to find pid %d\n",
> eventfd_copy.target_pid);
> +               goto out;
> +       }
> +
> +       ret = -ESTALE;
> +       files = get_files_struct(current);
> +       if (files == NULL) {
> +               pr_info("Failed to get current files struct\n");
> +               goto out_task;
> +       }
>
> -               if (file == NULL) {
> -                       pr_debug("Failed to get file from source pid\n");
> -                       return 0;
> -               }
> -
> -               /*
> -                * Release the existing eventfd in the source process
> -                */
> -               spin_lock(&files->file_lock);
> -               fput(file);
> -               filp_close(file, files);
> -               fdt = files_fdtable(files);
> -               fdt->fd[eventfd_copy.source_fd] = NULL;
> -               spin_unlock(&files->file_lock);
> -
> -               /*
> -                * Find the file struct associated with the target fd.
> -                */
> -
> -               files = get_files_struct(task_target);
> -               if (files == NULL) {
> -                       pr_debug("Failed to get files struct\n");
> -                       return -EFAULT;
> -               }
> -
> -               rcu_read_lock();
> -               file = fcheck_files(files, eventfd_copy.target_fd);
> -               if (file) {
> -                       if (file->f_mode & FMODE_PATH ||
> -                               !atomic_long_inc_not_zero(&file->f_count))
> -                                       file = NULL;
> -               }
> -               rcu_read_unlock();
> +       ret = -EBADF;
> +       file = fget_from_files(files, eventfd_copy.source_fd);
> +
> +       if (file == NULL) {
> +               pr_info("Failed to get fd %d from source\n",
> +                       eventfd_copy.source_fd);
>                 put_files_struct(files);
> +               goto out_task;
> +       }
> +
> +       /*
> +        * Release the existing eventfd in the source process
> +        */
> +       spin_lock(&files->file_lock);
> +       fput(file);
> +       filp_close(file, files);
> +       fdt = files_fdtable(files);
> +       fdt->fd[eventfd_copy.source_fd] = NULL;
> +       spin_unlock(&files->file_lock);
> +
> +       put_files_struct(files);
> +
> +       /*
> +        * Find the file struct associated with the target fd.
> +        */
> +
> +       ret = -ESTALE;
> +       files = get_files_struct(task_target);
> +       if (files == NULL) {
> +               pr_info("Failed to get target files struct\n");
> +               goto out_task;
> +       }
> +
> +       ret = -EBADF;
> +       file = fget_from_files(files, eventfd_copy.target_fd);
> +       put_files_struct(files);
> +
> +       if (file == NULL) {
> +               pr_info("Failed to get fd %d from target\n",
> +                       eventfd_copy.target_fd);
> +               goto out_task;
> +       }
>
> -               if (file == NULL) {
> -                       pr_debug("Failed to get file from target pid\n");
> -                       return 0;
> -               }
> +       /*
> +        * Install the file struct from the target process into the
> +        * file desciptor of the source process,
> +        */
>
> -               /*
> -                * Install the file struct from the target process into the
> -                * file desciptor of the source process,
> -                */
> +       fd_install(eventfd_copy.source_fd, file);
> +       ret = 0;
>
> -               fd_install(eventfd_copy.source_fd, file);
> +out_task:
> +       put_task_struct(task_target);
> +out:
> +       return ret;
> +}
>
> -               return 0;
> +static long
> +eventfd_link_ioctl(struct file *f, unsigned int ioctl, unsigned long arg)
> +{
> +       long ret = -ENOIOCTLCMD;
>
> -       default:
> -               return -ENOIOCTLCMD;
> +       switch (ioctl) {
> +       case EVENTFD_COPY:
> +               ret = eventfd_link_ioctl_copy(arg);
> +               break;
>         }
> +
> +       return ret;
>  }
>
>  static const struct file_operations eventfd_link_fops = {
> --
> 1.9.1
>
>