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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-20 13:28:18 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-20 13:28:18 -0700 |
commit | f0691533b756931089902464ca15afc218a49d70 (patch) | |
tree | 7d72b43866be5ae5507efb9c2976059d5d5cc0f1 /lib/dma-noop.c | |
parent | 2b2f72d8ce59acce95ceb156f0f31b848e32e6d4 (diff) | |
parent | c67f5db82027ba6d2ea4ac9176bc45996a03ae6a (diff) | |
download | linux-f0691533b756931089902464ca15afc218a49d70.tar.gz linux-f0691533b756931089902464ca15afc218a49d70.tar.bz2 linux-f0691533b756931089902464ca15afc218a49d70.zip |
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull virtio/vhost updates from Michael Tsirkin:
"New features, performance improvements, cleanups:
- basic polling support for vhost
- rework virtio to optionally use DMA API, fixing it on Xen
- balloon stats gained a new entry
- using the new napi_alloc_skb speeds up virtio net
- virtio blk stats can now be read while another VCPU is busy
inflating or deflating the balloon
plus misc cleanups in various places"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio_net: replace netdev_alloc_skb_ip_align() with napi_alloc_skb()
vhost_net: basic polling support
vhost: introduce vhost_vq_avail_empty()
vhost: introduce vhost_has_work()
virtio_balloon: Allow to resize and update the balloon stats in parallel
virtio_balloon: Use a workqueue instead of "vballoon" kthread
virtio/s390: size of SET_IND payload
virtio/s390: use dev_to_virtio
vhost: rename vhost_init_used()
vhost: rename cross-endian helpers
virtio_blk: VIRTIO_BLK_F_WCE->VIRTIO_BLK_F_FLUSH
vring: Use the DMA API on Xen
virtio_pci: Use the DMA API if enabled
virtio_mmio: Use the DMA API if enabled
virtio: Add improved queue allocation API
virtio_ring: Support DMA APIs
vring: Introduce vring_use_dma_api()
s390/dma: Allow per device dma ops
alpha/dma: use common noop dma ops
dma: Provide simple noop dma ops
Diffstat (limited to 'lib/dma-noop.c')
-rw-r--r-- | lib/dma-noop.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/lib/dma-noop.c b/lib/dma-noop.c new file mode 100644 index 000000000000..72145646857e --- /dev/null +++ b/lib/dma-noop.c @@ -0,0 +1,75 @@ +/* + * lib/dma-noop.c + * + * Simple DMA noop-ops that map 1:1 with memory + */ +#include <linux/export.h> +#include <linux/mm.h> +#include <linux/dma-mapping.h> +#include <linux/scatterlist.h> + +static void *dma_noop_alloc(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, + struct dma_attrs *attrs) +{ + void *ret; + + ret = (void *)__get_free_pages(gfp, get_order(size)); + if (ret) + *dma_handle = virt_to_phys(ret); + return ret; +} + +static void dma_noop_free(struct device *dev, size_t size, + void *cpu_addr, dma_addr_t dma_addr, + struct dma_attrs *attrs) +{ + free_pages((unsigned long)cpu_addr, get_order(size)); +} + +static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + struct dma_attrs *attrs) +{ + return page_to_phys(page) + offset; +} + +static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents, + enum dma_data_direction dir, struct dma_attrs *attrs) +{ + int i; + struct scatterlist *sg; + + for_each_sg(sgl, sg, nents, i) { + void *va; + + BUG_ON(!sg_page(sg)); + va = sg_virt(sg); + sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va); + sg_dma_len(sg) = sg->length; + } + + return nents; +} + +static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr) +{ + return 0; +} + +static int dma_noop_supported(struct device *dev, u64 mask) +{ + return 1; +} + +struct dma_map_ops dma_noop_ops = { + .alloc = dma_noop_alloc, + .free = dma_noop_free, + .map_page = dma_noop_map_page, + .map_sg = dma_noop_map_sg, + .mapping_error = dma_noop_mapping_error, + .dma_supported = dma_noop_supported, +}; + +EXPORT_SYMBOL(dma_noop_ops); |