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| author | Jan Kara <jack@suse.cz> | 2015-03-17 14:56:31 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@osg.samsung.com> | 2015-05-01 13:17:27 +0300 |
| commit | 48b25a3a713b90988b6882d318f7c0a6bed9aabc (patch) | |
| tree | 818fab949bd94cbafbef001ca307d4756dd9df1c /drivers/media/v4l2-core/videobuf2-dma-contig.c | |
| parent | 9c3f205252f8ae2af9794d68bcbfc49fb0812ccf (diff) | |
| download | linux-48b25a3a713b90988b6882d318f7c0a6bed9aabc.tar.xz | |
[media] vb2: Push mmap_sem down to memops
Currently vb2 core acquires mmap_sem just around call to
__qbuf_userptr(). However since commit f035eb4e976ef5 (videobuf2: fix
lockdep warning) it isn't necessary to acquire it so early as we no
longer have to drop queue mutex before acquiring mmap_sem. So push
acquisition of mmap_sem down into .get_userptr and .put_userptr memops
so that the semaphore is acquired for a shorter time and it is clearer
what it is needed for.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Diffstat (limited to 'drivers/media/v4l2-core/videobuf2-dma-contig.c')
| -rw-r--r-- | drivers/media/v4l2-core/videobuf2-dma-contig.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 644dec73d220..620c4aa78881 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -532,7 +532,9 @@ static void vb2_dc_put_userptr(void *buf_priv) sg_free_table(sgt); kfree(sgt); } + down_read(¤t->mm->mmap_sem); vb2_put_vma(buf->vma); + up_read(¤t->mm->mmap_sem); kfree(buf); } @@ -616,6 +618,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, goto fail_buf; } + down_read(¤t->mm->mmap_sem); /* current->mm->mmap_sem is taken by videobuf2 core */ vma = find_vma(current->mm, vaddr); if (!vma) { @@ -642,6 +645,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, if (ret) { unsigned long pfn; if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) { + up_read(¤t->mm->mmap_sem); buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn); buf->size = size; kfree(pages); @@ -651,6 +655,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, pr_err("failed to get user pages\n"); goto fail_vma; } + up_read(¤t->mm->mmap_sem); sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) { @@ -713,10 +718,12 @@ fail_get_user_pages: while (n_pages) put_page(pages[--n_pages]); + down_read(¤t->mm->mmap_sem); fail_vma: vb2_put_vma(buf->vma); fail_pages: + up_read(¤t->mm->mmap_sem); kfree(pages); /* kfree is NULL-proof */ fail_buf: |