This patch refactors the vfio_iommu_type1_ioctl() to use switch instead of
if-else, and each cmd got a helper function.

Cc: Kevin Tian <kevin.t...@intel.com>
CC: Jacob Pan <jacob.jun....@linux.intel.com>
Cc: Alex Williamson <alex.william...@redhat.com>
Cc: Eric Auger <eric.au...@redhat.com>
Cc: Jean-Philippe Brucker <jean-phili...@linaro.org>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Lu Baolu <baolu...@linux.intel.com>
Suggested-by: Christoph Hellwig <h...@infradead.org>
Signed-off-by: Liu Yi L <yi.l....@intel.com>
---
 drivers/vfio/vfio_iommu_type1.c | 392 ++++++++++++++++++++++------------------
 1 file changed, 213 insertions(+), 179 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 5e556ac..7accb59 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2453,6 +2453,23 @@ static int vfio_domains_have_iommu_cache(struct 
vfio_iommu *iommu)
        return ret;
 }
 
+static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
+                                           unsigned long arg)
+{
+       switch (arg) {
+       case VFIO_TYPE1_IOMMU:
+       case VFIO_TYPE1v2_IOMMU:
+       case VFIO_TYPE1_NESTING_IOMMU:
+               return 1;
+       case VFIO_DMA_CC_IOMMU:
+               if (!iommu)
+                       return 0;
+               return vfio_domains_have_iommu_cache(iommu);
+       default:
+               return 0;
+       }
+}
+
 static int vfio_iommu_iova_add_cap(struct vfio_info_cap *caps,
                 struct vfio_iommu_type1_info_cap_iova_range *cap_iovas,
                 size_t size)
@@ -2529,238 +2546,255 @@ static int vfio_iommu_migration_build_caps(struct 
vfio_iommu *iommu,
        return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
 }
 
-static long vfio_iommu_type1_ioctl(void *iommu_data,
-                                  unsigned int cmd, unsigned long arg)
+static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu,
+                                    unsigned long arg)
 {
-       struct vfio_iommu *iommu = iommu_data;
+       struct vfio_iommu_type1_info info;
        unsigned long minsz;
+       struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
+       unsigned long capsz;
+       int ret;
 
-       if (cmd == VFIO_CHECK_EXTENSION) {
-               switch (arg) {
-               case VFIO_TYPE1_IOMMU:
-               case VFIO_TYPE1v2_IOMMU:
-               case VFIO_TYPE1_NESTING_IOMMU:
-                       return 1;
-               case VFIO_DMA_CC_IOMMU:
-                       if (!iommu)
-                               return 0;
-                       return vfio_domains_have_iommu_cache(iommu);
-               default:
-                       return 0;
-               }
-       } else if (cmd == VFIO_IOMMU_GET_INFO) {
-               struct vfio_iommu_type1_info info;
-               struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
-               unsigned long capsz;
-               int ret;
-
-               minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
+       minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
 
-               /* For backward compatibility, cannot require this */
-               capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
+       /* For backward compatibility, cannot require this */
+       capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
 
-               if (copy_from_user(&info, (void __user *)arg, minsz))
-                       return -EFAULT;
+       if (copy_from_user(&info, (void __user *)arg, minsz))
+               return -EFAULT;
 
-               if (info.argsz < minsz)
-                       return -EINVAL;
+       if (info.argsz < minsz)
+               return -EINVAL;
 
-               if (info.argsz >= capsz) {
-                       minsz = capsz;
-                       info.cap_offset = 0; /* output, no-recopy necessary */
-               }
+       if (info.argsz >= capsz) {
+               minsz = capsz;
+               info.cap_offset = 0; /* output, no-recopy necessary */
+       }
 
-               mutex_lock(&iommu->lock);
-               info.flags = VFIO_IOMMU_INFO_PGSIZES;
+       mutex_lock(&iommu->lock);
+       info.flags = VFIO_IOMMU_INFO_PGSIZES;
 
-               info.iova_pgsizes = iommu->pgsize_bitmap;
+       info.iova_pgsizes = iommu->pgsize_bitmap;
 
-               ret = vfio_iommu_migration_build_caps(iommu, &caps);
+       ret = vfio_iommu_migration_build_caps(iommu, &caps);
 
-               if (!ret)
-                       ret = vfio_iommu_iova_build_caps(iommu, &caps);
+       if (!ret)
+               ret = vfio_iommu_iova_build_caps(iommu, &caps);
 
-               mutex_unlock(&iommu->lock);
+       mutex_unlock(&iommu->lock);
 
-               if (ret)
-                       return ret;
+       if (ret)
+               return ret;
 
-               if (caps.size) {
-                       info.flags |= VFIO_IOMMU_INFO_CAPS;
+       if (caps.size) {
+               info.flags |= VFIO_IOMMU_INFO_CAPS;
 
-                       if (info.argsz < sizeof(info) + caps.size) {
-                               info.argsz = sizeof(info) + caps.size;
-                       } else {
-                               vfio_info_cap_shift(&caps, sizeof(info));
-                               if (copy_to_user((void __user *)arg +
-                                               sizeof(info), caps.buf,
-                                               caps.size)) {
-                                       kfree(caps.buf);
-                                       return -EFAULT;
-                               }
-                               info.cap_offset = sizeof(info);
+               if (info.argsz < sizeof(info) + caps.size) {
+                       info.argsz = sizeof(info) + caps.size;
+               } else {
+                       vfio_info_cap_shift(&caps, sizeof(info));
+                       if (copy_to_user((void __user *)arg +
+                                       sizeof(info), caps.buf,
+                                       caps.size)) {
+                               kfree(caps.buf);
+                               return -EFAULT;
                        }
-
-                       kfree(caps.buf);
+                       info.cap_offset = sizeof(info);
                }
 
-               return copy_to_user((void __user *)arg, &info, minsz) ?
-                       -EFAULT : 0;
+               kfree(caps.buf);
+       }
 
-       } else if (cmd == VFIO_IOMMU_MAP_DMA) {
-               struct vfio_iommu_type1_dma_map map;
-               uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
-                               VFIO_DMA_MAP_FLAG_WRITE;
+       return copy_to_user((void __user *)arg, &info, minsz) ?
+                       -EFAULT : 0;
+}
 
-               minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
+static int vfio_iommu_type1_map_dma(struct vfio_iommu *iommu,
+                                   unsigned long arg)
+{
+       struct vfio_iommu_type1_dma_map map;
+       unsigned long minsz;
+       uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
+                       VFIO_DMA_MAP_FLAG_WRITE;
 
-               if (copy_from_user(&map, (void __user *)arg, minsz))
-                       return -EFAULT;
+       minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
 
-               if (map.argsz < minsz || map.flags & ~mask)
-                       return -EINVAL;
+       if (copy_from_user(&map, (void __user *)arg, minsz))
+               return -EFAULT;
 
-               return vfio_dma_do_map(iommu, &map);
+       if (map.argsz < minsz || map.flags & ~mask)
+               return -EINVAL;
 
-       } else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
-               struct vfio_iommu_type1_dma_unmap unmap;
-               struct vfio_bitmap bitmap = { 0 };
-               int ret;
+       return vfio_dma_do_map(iommu, &map);
+}
 
-               minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
+static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
+                                     unsigned long arg)
+{
+       struct vfio_iommu_type1_dma_unmap unmap;
+       struct vfio_bitmap bitmap = { 0 };
+       unsigned long minsz;
+       long ret;
 
-               if (copy_from_user(&unmap, (void __user *)arg, minsz))
-                       return -EFAULT;
+       minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
 
-               if (unmap.argsz < minsz ||
-                   unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
-                       return -EINVAL;
+       if (copy_from_user(&unmap, (void __user *)arg, minsz))
+               return -EFAULT;
 
-               if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
-                       unsigned long pgshift;
+       if (unmap.argsz < minsz ||
+           unmap.flags & ~VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP)
+               return -EINVAL;
 
-                       if (unmap.argsz < (minsz + sizeof(bitmap)))
-                               return -EINVAL;
+       if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
+               unsigned long pgshift;
 
-                       if (copy_from_user(&bitmap,
-                                          (void __user *)(arg + minsz),
-                                          sizeof(bitmap)))
-                               return -EFAULT;
+               if (unmap.argsz < (minsz + sizeof(bitmap)))
+                       return -EINVAL;
 
-                       if (!access_ok((void __user *)bitmap.data, bitmap.size))
-                               return -EINVAL;
+               if (copy_from_user(&bitmap,
+                                  (void __user *)(arg + minsz),
+                                  sizeof(bitmap)))
+                       return -EFAULT;
 
-                       pgshift = __ffs(bitmap.pgsize);
-                       ret = verify_bitmap_size(unmap.size >> pgshift,
-                                                bitmap.size);
-                       if (ret)
-                               return ret;
-               }
+               if (!access_ok((void __user *)bitmap.data, bitmap.size))
+                       return -EINVAL;
 
-               ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap);
+               pgshift = __ffs(bitmap.pgsize);
+               ret = verify_bitmap_size(unmap.size >> pgshift,
+                                        bitmap.size);
                if (ret)
                        return ret;
+       }
+
+       ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap);
+       if (ret)
+               return ret;
 
-               return copy_to_user((void __user *)arg, &unmap, minsz) ?
+       return copy_to_user((void __user *)arg, &unmap, minsz) ?
                        -EFAULT : 0;
-       } else if (cmd == VFIO_IOMMU_DIRTY_PAGES) {
-               struct vfio_iommu_type1_dirty_bitmap dirty;
-               uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
-                               VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
-                               VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
-               int ret = 0;
+}
 
-               if (!iommu->v2)
-                       return -EACCES;
+static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
+                                       unsigned long arg)
+{
+       struct vfio_iommu_type1_dirty_bitmap dirty;
+       uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
+                       VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
+                       VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
+       unsigned long minsz;
+       int ret = 0;
 
-               minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap,
-                                   flags);
+       if (!iommu->v2)
+               return -EACCES;
 
-               if (copy_from_user(&dirty, (void __user *)arg, minsz))
-                       return -EFAULT;
+       minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap,
+                           flags);
 
-               if (dirty.argsz < minsz || dirty.flags & ~mask)
-                       return -EINVAL;
+       if (copy_from_user(&dirty, (void __user *)arg, minsz))
+               return -EFAULT;
+
+       if (dirty.argsz < minsz || dirty.flags & ~mask)
+               return -EINVAL;
+
+       /* only one flag should be set at a time */
+       if (__ffs(dirty.flags) != __fls(dirty.flags))
+               return -EINVAL;
+
+       if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
+               size_t pgsize;
 
-               /* only one flag should be set at a time */
-               if (__ffs(dirty.flags) != __fls(dirty.flags))
+               mutex_lock(&iommu->lock);
+               pgsize = 1 << __ffs(iommu->pgsize_bitmap);
+               if (!iommu->dirty_page_tracking) {
+                       ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
+                       if (!ret)
+                               iommu->dirty_page_tracking = true;
+               }
+               mutex_unlock(&iommu->lock);
+               return ret;
+       } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) {
+               mutex_lock(&iommu->lock);
+               if (iommu->dirty_page_tracking) {
+                       iommu->dirty_page_tracking = false;
+                       vfio_dma_bitmap_free_all(iommu);
+               }
+               mutex_unlock(&iommu->lock);
+               return 0;
+       } else if (dirty.flags &
+                        VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
+               struct vfio_iommu_type1_dirty_bitmap_get range;
+               unsigned long pgshift;
+               size_t data_size = dirty.argsz - minsz;
+               size_t iommu_pgsize;
+
+               if (!data_size || data_size < sizeof(range))
                        return -EINVAL;
 
-               if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
-                       size_t pgsize;
+               if (copy_from_user(&range, (void __user *)(arg + minsz),
+                                  sizeof(range)))
+                       return -EFAULT;
 
-                       mutex_lock(&iommu->lock);
-                       pgsize = 1 << __ffs(iommu->pgsize_bitmap);
-                       if (!iommu->dirty_page_tracking) {
-                               ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
-                               if (!ret)
-                                       iommu->dirty_page_tracking = true;
-                       }
-                       mutex_unlock(&iommu->lock);
+               if (range.iova + range.size < range.iova)
+                       return -EINVAL;
+               if (!access_ok((void __user *)range.bitmap.data,
+                              range.bitmap.size))
+                       return -EINVAL;
+
+               pgshift = __ffs(range.bitmap.pgsize);
+               ret = verify_bitmap_size(range.size >> pgshift,
+                                        range.bitmap.size);
+               if (ret)
                        return ret;
-               } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) {
-                       mutex_lock(&iommu->lock);
-                       if (iommu->dirty_page_tracking) {
-                               iommu->dirty_page_tracking = false;
-                               vfio_dma_bitmap_free_all(iommu);
-                       }
-                       mutex_unlock(&iommu->lock);
-                       return 0;
-               } else if (dirty.flags &
-                                VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
-                       struct vfio_iommu_type1_dirty_bitmap_get range;
-                       unsigned long pgshift;
-                       size_t data_size = dirty.argsz - minsz;
-                       size_t iommu_pgsize;
-
-                       if (!data_size || data_size < sizeof(range))
-                               return -EINVAL;
-
-                       if (copy_from_user(&range, (void __user *)(arg + minsz),
-                                          sizeof(range)))
-                               return -EFAULT;
 
-                       if (range.iova + range.size < range.iova)
-                               return -EINVAL;
-                       if (!access_ok((void __user *)range.bitmap.data,
-                                      range.bitmap.size))
-                               return -EINVAL;
+               mutex_lock(&iommu->lock);
 
-                       pgshift = __ffs(range.bitmap.pgsize);
-                       ret = verify_bitmap_size(range.size >> pgshift,
-                                                range.bitmap.size);
-                       if (ret)
-                               return ret;
+               iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
 
-                       mutex_lock(&iommu->lock);
+               /* allow only smallest supported pgsize */
+               if (range.bitmap.pgsize != iommu_pgsize) {
+                       ret = -EINVAL;
+                       goto out_unlock;
+               }
+               if (range.iova & (iommu_pgsize - 1)) {
+                       ret = -EINVAL;
+                       goto out_unlock;
+               }
+               if (!range.size || range.size & (iommu_pgsize - 1)) {
+                       ret = -EINVAL;
+                       goto out_unlock;
+               }
 
-                       iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);
+               if (iommu->dirty_page_tracking)
+                       ret = vfio_iova_dirty_bitmap(range.bitmap.data,
+                                       iommu, range.iova, range.size,
+                                       range.bitmap.pgsize);
+               else
+                       ret = -EINVAL;
+out_unlock:
+               mutex_unlock(&iommu->lock);
 
-                       /* allow only smallest supported pgsize */
-                       if (range.bitmap.pgsize != iommu_pgsize) {
-                               ret = -EINVAL;
-                               goto out_unlock;
-                       }
-                       if (range.iova & (iommu_pgsize - 1)) {
-                               ret = -EINVAL;
-                               goto out_unlock;
-                       }
-                       if (!range.size || range.size & (iommu_pgsize - 1)) {
-                               ret = -EINVAL;
-                               goto out_unlock;
-                       }
+               return ret;
+       }
 
-                       if (iommu->dirty_page_tracking)
-                               ret = vfio_iova_dirty_bitmap(range.bitmap.data,
-                                               iommu, range.iova, range.size,
-                                               range.bitmap.pgsize);
-                       else
-                               ret = -EINVAL;
-out_unlock:
-                       mutex_unlock(&iommu->lock);
+       return -EINVAL;
+}
 
-                       return ret;
-               }
+static long vfio_iommu_type1_ioctl(void *iommu_data,
+                                  unsigned int cmd, unsigned long arg)
+{
+       struct vfio_iommu *iommu = iommu_data;
+
+       switch (cmd) {
+       case VFIO_CHECK_EXTENSION:
+               return vfio_iommu_type1_check_extension(iommu, arg);
+       case VFIO_IOMMU_GET_INFO:
+               return vfio_iommu_type1_get_info(iommu, arg);
+       case VFIO_IOMMU_MAP_DMA:
+               return vfio_iommu_type1_map_dma(iommu, arg);
+       case VFIO_IOMMU_UNMAP_DMA:
+               return vfio_iommu_type1_unmap_dma(iommu, arg);
+       case VFIO_IOMMU_DIRTY_PAGES:
+               return vfio_iommu_type1_dirty_pages(iommu, arg);
        }
 
        return -ENOTTY;
-- 
2.7.4

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