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V4L/DVB (11840): change kmalloc to vmalloc for sglist allocation in videobuf_dma_map/unmap

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Change kmalloc()/kfree() to vmalloc()/vfree() for sglist allocation
during videobuf_dma_map() and videobuf_dma_unmap()

High resolution sensors might require too many contiguous pages
to be allocated for sglist by kmalloc() during videobuf_dma_map()
(i.e. 256Kib for 8MP sensor).
In such situations, kmalloc() could face some problem to find the
required free memory. vmalloc() is a safer solution instead, as the
allocated memory does not need to be contiguous.

Signed-off-by: David Cohen <david.cohen@nokia.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Cohen David.A 2009-05-11 11:00:20 -03:00 committed by Mauro Carvalho Chehab
parent 04a37e0f32
commit 1010ed1327
2 changed files with 11 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/video4linux/CARDLIST.em28xx
View File

@ -62,3 +62,5 @@
64 -> Easy Cap Capture DC-60 (em2860) 64 -> Easy Cap Capture DC-60 (em2860)
65 -> IO-DATA GV-MVP/SZ (em2820/em2840) [04bb:0515] 65 -> IO-DATA GV-MVP/SZ (em2820/em2840) [04bb:0515]
66 -> Empire dual TV (em2880) 66 -> Empire dual TV (em2880)
67 -> Terratec Grabby (em2860) [0ccd:0096]
68 -> Terratec AV350 (em2860) [0ccd:0084]

17
drivers/media/video/videobuf-dma-sg.c
View File

@ -58,9 +58,10 @@ videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages)
struct page *pg; struct page *pg;
int i; int i;
sglist = kcalloc(nr_pages, sizeof(struct scatterlist), GFP_KERNEL); sglist = vmalloc(nr_pages * sizeof(*sglist));
if (NULL == sglist) if (NULL == sglist)
return NULL; return NULL;
memset(sglist, 0, nr_pages * sizeof(*sglist));
sg_init_table(sglist, nr_pages); sg_init_table(sglist, nr_pages);
for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) { for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
pg = vmalloc_to_page(virt); pg = vmalloc_to_page(virt);
@ -72,7 +73,7 @@ videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages)
return sglist; return sglist;
err: err:
kfree(sglist); vfree(sglist);
return NULL; return NULL;
} }
@ -84,7 +85,7 @@ videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset)
if (NULL == pages[0]) if (NULL == pages[0])
return NULL; return NULL;
sglist = kmalloc(nr_pages * sizeof(*sglist), GFP_KERNEL); sglist = vmalloc(nr_pages * sizeof(*sglist));
if (NULL == sglist) if (NULL == sglist)
return NULL; return NULL;
sg_init_table(sglist, nr_pages); sg_init_table(sglist, nr_pages);
@ -104,12 +105,12 @@ videobuf_pages_to_sg(struct page **pages, int nr_pages, int offset)
nopage: nopage:
dprintk(2,"sgl: oops - no page\n"); dprintk(2,"sgl: oops - no page\n");
kfree(sglist); vfree(sglist);
return NULL; return NULL;
highmem: highmem:
dprintk(2,"sgl: oops - highmem page\n"); dprintk(2,"sgl: oops - highmem page\n");
kfree(sglist); vfree(sglist);
return NULL; return NULL;
} }
@ -230,7 +231,7 @@ int videobuf_dma_map(struct videobuf_queue* q, struct videobuf_dmabuf *dma)
(dma->vmalloc,dma->nr_pages); (dma->vmalloc,dma->nr_pages);
} }
if (dma->bus_addr) { if (dma->bus_addr) {
dma->sglist = kmalloc(sizeof(struct scatterlist), GFP_KERNEL); dma->sglist = vmalloc(sizeof(*dma->sglist));
if (NULL != dma->sglist) { if (NULL != dma->sglist) {
dma->sglen = 1; dma->sglen = 1;
sg_dma_address(&dma->sglist[0]) = dma->bus_addr & PAGE_MASK; sg_dma_address(&dma->sglist[0]) = dma->bus_addr & PAGE_MASK;
@ -248,7 +249,7 @@ int videobuf_dma_map(struct videobuf_queue* q, struct videobuf_dmabuf *dma)
if (0 == dma->sglen) { if (0 == dma->sglen) {
printk(KERN_WARNING printk(KERN_WARNING
"%s: videobuf_map_sg failed\n",__func__); "%s: videobuf_map_sg failed\n",__func__);
kfree(dma->sglist); vfree(dma->sglist);
dma->sglist = NULL; dma->sglist = NULL;
dma->sglen = 0; dma->sglen = 0;
return -EIO; return -EIO;
@ -274,7 +275,7 @@ int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
dma_unmap_sg(q->dev, dma->sglist, dma->nr_pages, dma->direction); dma_unmap_sg(q->dev, dma->sglist, dma->nr_pages, dma->direction);
kfree(dma->sglist); vfree(dma->sglist);
dma->sglist = NULL; dma->sglist = NULL;
dma->sglen = 0; dma->sglen = 0;
return 0; return 0;