[Intel-gfx] [PATCH v6 74/99] usb: Convert xhci-mem to XArray
Matthew Wilcox
willy at infradead.org
Wed Jan 17 20:21:38 UTC 2018
From: Matthew Wilcox <mawilcox at microsoft.com>
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 at microsoft.com>
---
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
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