From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> The XArray API is a slightly better fit for xhci_insert_segment_mapping() than the radix tree API was. Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> --- drivers/usb/host/xhci-mem.c | 68 +++++++++++++++++++-------------------------- drivers/usb/host/xhci.h | 6 ++-- 2 files changed, 32 insertions(+), 42 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 3a29b32a3bd0..a2e15a9abc30 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -149,70 +149,60 @@ static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring, } /* - * We need a radix tree for mapping physical addresses of TRBs to which stream - * ID they belong to. We need to do this because the host controller won't tell + * We need to map physical addresses of TRBs to the stream ID they belong to. + * We need to do this because the host controller won't tell * us which stream ring the TRB came from. We could store the stream ID in an * event data TRB, but that doesn't help us for the cancellation case, since the * endpoint may stop before it reaches that event data TRB. * - * The radix tree maps the upper portion of the TRB DMA address to a ring + * The xarray maps the upper portion of the TRB DMA address to a ring * segment that has the same upper portion of DMA addresses. For example, say I * have segments of size 1KB, that are always 1KB aligned. A segment may * start at 0x10c91000 and end at 0x10c913f0. If I use the upper 10 bits, the - * key to the stream ID is 0x43244. I can use the DMA address of the TRB to - * pass the radix tree a key to get the right stream ID: + * index of the stream ID is 0x43244. I can use the DMA address of the TRB as + * the xarray index to get the right stream ID: * * 0x10c90fff >> 10 = 0x43243 * 0x10c912c0 >> 10 = 0x43244 * 0x10c91400 >> 10 = 0x43245 * * Obviously, only those TRBs with DMA addresses that are within the segment - * will make the radix tree return the stream ID for that ring. + * will make the xarray return the stream ID for that ring. * - * Caveats for the radix tree: + * Caveats for the xarray: * - * The radix tree uses an unsigned long as a key pair. On 32-bit systems, an + * The xarray uses an unsigned long for the index. On 32-bit systems, an * unsigned long will be 32-bits; on a 64-bit system an unsigned long will be * 64-bits. Since we only request 32-bit DMA addresses, we can use that as the - * key on 32-bit or 64-bit systems (it would also be fine if we asked for 64-bit - * PCI DMA addresses on a 64-bit system). There might be a problem on 32-bit - * extended systems (where the DMA address can be bigger than 32-bits), + * index on 32-bit or 64-bit systems (it would also be fine if we asked for + * 64-bit PCI DMA addresses on a 64-bit system). There might be a problem on + * 32-bit extended systems (where the DMA address can be bigger than 32-bits), * if we allow the PCI dma mask to be bigger than 32-bits. So don't do that. */ -static int xhci_insert_segment_mapping(struct radix_tree_root *trb_address_map, + +static unsigned long trb_index(dma_addr_t dma) +{ + return (unsigned long)(dma >> TRB_SEGMENT_SHIFT); +} + +static int xhci_insert_segment_mapping(struct xarray *trb_address_map, struct xhci_ring *ring, struct xhci_segment *seg, - gfp_t mem_flags) + gfp_t gfp) { - unsigned long key; - int ret; - - key = (unsigned long)(seg->dma >> TRB_SEGMENT_SHIFT); /* Skip any segments that were already added. */ - if (radix_tree_lookup(trb_address_map, key)) - return 0; - - ret = radix_tree_maybe_preload(mem_flags); - if (ret) - return ret; - ret = radix_tree_insert(trb_address_map, - key, ring); - radix_tree_preload_end(); - return ret; + return xa_err(xa_cmpxchg(trb_address_map, trb_index(seg->dma), NULL, + ring, gfp)); } -static void xhci_remove_segment_mapping(struct radix_tree_root *trb_address_map, +static void xhci_remove_segment_mapping(struct xarray *trb_address_map, struct xhci_segment *seg) { - unsigned long key; - - key = (unsigned long)(seg->dma >> TRB_SEGMENT_SHIFT); - if (radix_tree_lookup(trb_address_map, key)) - radix_tree_delete(trb_address_map, key); + xa_erase(trb_address_map, trb_index(seg->dma)); } static int xhci_update_stream_segment_mapping( - struct radix_tree_root *trb_address_map, + struct xarray *trb_address_map, struct xhci_ring *ring, struct xhci_segment *first_seg, struct xhci_segment *last_seg, @@ -574,8 +564,8 @@ struct xhci_ring *xhci_dma_to_transfer_ring( u64 address) { if (ep->ep_state & EP_HAS_STREAMS) - return radix_tree_lookup(&ep->stream_info->trb_address_map, - address >> TRB_SEGMENT_SHIFT); + return xa_load(&ep->stream_info->trb_address_map, + trb_index(address)); return ep->ring; } @@ -654,10 +644,10 @@ struct xhci_stream_info *xhci_alloc_stream_info(struct xhci_hcd *xhci, if (!stream_info->free_streams_command) goto cleanup_ctx; - INIT_RADIX_TREE(&stream_info->trb_address_map, GFP_ATOMIC); + xa_init(&stream_info->trb_address_map); /* Allocate rings for all the streams that the driver will use, - * and add their segment DMA addresses to the radix tree. + * and add their segment DMA addresses to the map. * Stream 0 is reserved. */ @@ -2376,7 +2366,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags) * Initialize the ring segment pool. The ring must be a contiguous * structure comprised of TRBs. The TRBs must be 16 byte aligned, * however, the command ring segment needs 64-byte aligned segments - * and our use of dma addresses in the trb_address_map radix tree needs + * and our use of dma addresses in the trb_address_map xarray needs * TRB_SEGMENT_SIZE alignment, so we pick the greater alignment need. */ xhci->segment_pool = dma_pool_create("xHCI ring segments", dev, diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 054ce74524af..e8208a3eee3c 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -15,7 +15,7 @@ #include <linux/usb.h> #include <linux/timer.h> #include <linux/kernel.h> -#include <linux/radix-tree.h> +#include <linux/xarray.h> #include <linux/usb/hcd.h> #include <linux/io-64-nonatomic-lo-hi.h> @@ -837,7 +837,7 @@ struct xhci_stream_info { unsigned int num_stream_ctxs; dma_addr_t ctx_array_dma; /* For mapping physical TRB addresses to segments in stream rings */ - struct radix_tree_root trb_address_map; + struct xarray trb_address_map; struct xhci_command *free_streams_command; }; @@ -1584,7 +1584,7 @@ struct xhci_ring { unsigned int bounce_buf_len; enum xhci_ring_type type; bool last_td_was_short; - struct radix_tree_root *trb_address_map; + struct xarray *trb_address_map; }; struct xhci_erst_entry { -- 2.15.1 -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html