Commit 7fd4b41f053681cccf188cc1731ae43fe38fa969
Committed by
Mauro Carvalho Chehab
Mauro Carvalho Chehab
1 parent
0d44b1235c
Exists in
master
and in
4 other branches
[media] ivtv: yuv: handle get_user_pages() -errno returns
get_user_pages() may return -errno, such as -EFAULT. So don't blindly use its return value as an offset into dma->map[] for the next get_user_pages() call. Since we'll give up and return an error if either fails, don't even make the second call if the first failed to give us exactly what we were looking for. The old code would also call put_page() on as many elements of dma->map[] as we'd asked for, regardless of how many were valid. [Andy Walls modified this patch to return -EFAULT instead of -EINVAL as Paul's observation "I'm not sure -EINVAL is the best return code vs -EFAULT or -ENOMEM, [...]" was correct. The return value bubbles up as a return code for write(), for which the V4L2 API spec indicates EINVAL is incorrect and EFAULT is correct.] Signed-off-by: Paul Cassella <fortytwo-ivtv@maneteren.bigw.org> Signed-off-by: Andy Walls <awalls@md.metrocast.net> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Showing 1 changed file with 40 additions and 12 deletions Side-by-side Diff
drivers/media/video/ivtv/ivtv-yuv.c
| ... | ... | @@ -77,22 +77,50 @@ |
| 77 | 77 | /* Get user pages for DMA Xfer */ |
| 78 | 78 | down_read(¤t->mm->mmap_sem); |
| 79 | 79 | y_pages = get_user_pages(current, current->mm, y_dma.uaddr, y_dma.page_count, 0, 1, &dma->map[0], NULL); |
| 80 | - uv_pages = get_user_pages(current, current->mm, uv_dma.uaddr, uv_dma.page_count, 0, 1, &dma->map[y_pages], NULL); | |
| 80 | + uv_pages = 0; /* silence gcc. value is set and consumed only if: */ | |
| 81 | + if (y_pages == y_dma.page_count) { | |
| 82 | + uv_pages = get_user_pages(current, current->mm, | |
| 83 | + uv_dma.uaddr, uv_dma.page_count, 0, 1, | |
| 84 | + &dma->map[y_pages], NULL); | |
| 85 | + } | |
| 81 | 86 | up_read(¤t->mm->mmap_sem); |
| 82 | 87 | |
| 83 | - dma->page_count = y_dma.page_count + uv_dma.page_count; | |
| 88 | + if (y_pages != y_dma.page_count || uv_pages != uv_dma.page_count) { | |
| 89 | + int rc = -EFAULT; | |
| 84 | 90 | |
| 85 | - if (y_pages + uv_pages != dma->page_count) { | |
| 86 | - IVTV_DEBUG_WARN | |
| 87 | - ("failed to map user pages, returned %d instead of %d\n", | |
| 88 | - y_pages + uv_pages, dma->page_count); | |
| 91 | + if (y_pages == y_dma.page_count) { | |
| 92 | + IVTV_DEBUG_WARN | |
| 93 | + ("failed to map uv user pages, returned %d " | |
| 94 | + "expecting %d\n", uv_pages, uv_dma.page_count); | |
| 89 | 95 | |
| 90 | - for (i = 0; i < dma->page_count; i++) { | |
| 91 | - put_page(dma->map[i]); | |
| 96 | + if (uv_pages >= 0) { | |
| 97 | + for (i = 0; i < uv_pages; i++) | |
| 98 | + put_page(dma->map[y_pages + i]); | |
| 99 | + rc = -EFAULT; | |
| 100 | + } else { | |
| 101 | + rc = uv_pages; | |
| 102 | + } | |
| 103 | + } else { | |
| 104 | + IVTV_DEBUG_WARN | |
| 105 | + ("failed to map y user pages, returned %d " | |
| 106 | + "expecting %d\n", y_pages, y_dma.page_count); | |
| 92 | 107 | } |
| 93 | - dma->page_count = 0; | |
| 94 | - return -EINVAL; | |
| 108 | + if (y_pages >= 0) { | |
| 109 | + for (i = 0; i < y_pages; i++) | |
| 110 | + put_page(dma->map[i]); | |
| 111 | + /* | |
| 112 | + * Inherit the -EFAULT from rc's | |
| 113 | + * initialization, but allow it to be | |
| 114 | + * overriden by uv_pages above if it was an | |
| 115 | + * actual errno. | |
| 116 | + */ | |
| 117 | + } else { | |
| 118 | + rc = y_pages; | |
| 119 | + } | |
| 120 | + return rc; | |
| 95 | 121 | } |
| 122 | + | |
| 123 | + dma->page_count = y_pages + uv_pages; | |
| 96 | 124 | |
| 97 | 125 | /* Fill & map SG List */ |
| 98 | 126 | if (ivtv_udma_fill_sg_list (dma, &uv_dma, ivtv_udma_fill_sg_list (dma, &y_dma, 0)) < 0) { |