[media] media: vb2: vmalloc-based allocator user pointer handling

This patch adds support for user pointer memory buffers to vmalloc
videobuf2 allocator.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/videobuf2-vmalloc.c b/drivers/media/video/videobuf2-vmalloc.c
index a3a884234059afcacae18bd2e246190bfcfa5970..4e789a178f8a810ca5ec6341e5d1db9d2ae34ce7 100644 (file)
--- a/drivers/media/video/videobuf2-vmalloc.c
+++ b/drivers/media/video/videobuf2-vmalloc.c
@@ -12,6 +12,7 @@
 
 #include <linux/module.h>
 #include <linux/mm.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
@@ -20,7 +21,10 @@
 
 struct vb2_vmalloc_buf {
        void                            *vaddr;
+       struct page                     **pages;
+       int                             write;
        unsigned long                   size;
+       unsigned int                    n_pages;
        atomic_t                        refcount;
        struct vb2_vmarea_handler       handler;
 };
@@ -31,7 +35,7 @@ static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
 {
        struct vb2_vmalloc_buf *buf;
 
-       buf = kzalloc(sizeof *buf, GFP_KERNEL);
+       buf = kzalloc(sizeof(*buf), GFP_KERNEL);
        if (!buf)
                return NULL;
 
@@ -42,15 +46,12 @@ static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
        buf->handler.arg = buf;
 
        if (!buf->vaddr) {
-               printk(KERN_ERR "vmalloc of size %ld failed\n", buf->size);
+               pr_debug("vmalloc of size %ld failed\n", buf->size);
                kfree(buf);
                return NULL;
        }
 
        atomic_inc(&buf->refcount);
-       printk(KERN_DEBUG "Allocated vmalloc buffer of size %ld at vaddr=%p\n",
-                       buf->size, buf->vaddr);
-
        return buf;
 }
 
@@ -59,21 +60,84 @@ static void vb2_vmalloc_put(void *buf_priv)
        struct vb2_vmalloc_buf *buf = buf_priv;
 
        if (atomic_dec_and_test(&buf->refcount)) {
-               printk(KERN_DEBUG "%s: Freeing vmalloc mem at vaddr=%p\n",
-                       __func__, buf->vaddr);
                vfree(buf->vaddr);
                kfree(buf);
        }
 }
 
-static void *vb2_vmalloc_vaddr(void *buf_priv)
+static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
+                                    unsigned long size, int write)
+{
+       struct vb2_vmalloc_buf *buf;
+       unsigned long first, last;
+       int n_pages, offset;
+
+       buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+       if (!buf)
+               return NULL;
+
+       buf->write = write;
+       offset = vaddr & ~PAGE_MASK;
+       buf->size = size;
+
+       first = vaddr >> PAGE_SHIFT;
+       last  = (vaddr + size - 1) >> PAGE_SHIFT;
+       buf->n_pages = last - first + 1;
+       buf->pages = kzalloc(buf->n_pages * sizeof(struct page *), GFP_KERNEL);
+       if (!buf->pages)
+               goto fail_pages_array_alloc;
+
+       /* current->mm->mmap_sem is taken by videobuf2 core */
+       n_pages = get_user_pages(current, current->mm, vaddr & PAGE_MASK,
+                                buf->n_pages, write, 1, /* force */
+                                buf->pages, NULL);
+       if (n_pages != buf->n_pages)
+               goto fail_get_user_pages;
+
+       buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1, PAGE_KERNEL);
+       if (!buf->vaddr)
+               goto fail_get_user_pages;
+
+       buf->vaddr += offset;
+       return buf;
+
+fail_get_user_pages:
+       pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
+                buf->n_pages);
+       while (--n_pages >= 0)
+               put_page(buf->pages[n_pages]);
+       kfree(buf->pages);
+
+fail_pages_array_alloc:
+       kfree(buf);
+
+       return NULL;
+}
+
+static void vb2_vmalloc_put_userptr(void *buf_priv)
 {
        struct vb2_vmalloc_buf *buf = buf_priv;
+       unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
+       unsigned int i;
+
+       if (vaddr)
+               vm_unmap_ram((void *)vaddr, buf->n_pages);
+       for (i = 0; i < buf->n_pages; ++i) {
+               if (buf->write)
+                       set_page_dirty_lock(buf->pages[i]);
+               put_page(buf->pages[i]);
+       }
+       kfree(buf->pages);
+       kfree(buf);
+}
 
-       BUG_ON(!buf);
+static void *vb2_vmalloc_vaddr(void *buf_priv)
+{
+       struct vb2_vmalloc_buf *buf = buf_priv;
 
        if (!buf->vaddr) {
-               printk(KERN_ERR "Address of an unallocated plane requested\n");
+               pr_err("Address of an unallocated plane requested "
+                      "or cannot map user pointer\n");
                return NULL;
        }
 
@@ -92,13 +156,13 @@ static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
        int ret;
 
        if (!buf) {
-               printk(KERN_ERR "No memory to map\n");
+               pr_err("No memory to map\n");
                return -EINVAL;
        }
 
        ret = remap_vmalloc_range(vma, buf->vaddr, 0);
        if (ret) {
-               printk(KERN_ERR "Remapping vmalloc memory, error: %d\n", ret);
+               pr_err("Remapping vmalloc memory, error: %d\n", ret);
                return ret;
        }
 
@@ -121,6 +185,8 @@ static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
 const struct vb2_mem_ops vb2_vmalloc_memops = {
        .alloc          = vb2_vmalloc_alloc,
        .put            = vb2_vmalloc_put,
+       .get_userptr    = vb2_vmalloc_get_userptr,
+       .put_userptr    = vb2_vmalloc_put_userptr,
        .vaddr          = vb2_vmalloc_vaddr,
        .mmap           = vb2_vmalloc_mmap,
        .num_users      = vb2_vmalloc_num_users,