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authorLinus Torvalds <torvalds@linux-foundation.org>2010-11-05 14:17:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-11-05 14:17:22 -0700
commitf69fa76482e654f7d94e4aa40ea0ebf04363396a (patch)
tree3cb1976afa6daf39a9e45551671ecfb5bb580e08 /drivers/firewire
parent2e5c36722d4c9c86281f25a1e963a6078c7fce6a (diff)
parent693fa7792e9db9f32da9436e633976fbacd04b55 (diff)
Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: firewire: ohci: fix race when reading count in AR descriptor firewire: ohci: avoid reallocation of AR buffers firewire: ohci: fix race in AR split packet handling firewire: ohci: fix buffer overflow in AR split packet handling
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/ohci.c88
1 files changed, 65 insertions, 23 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 9dcb17d51ae..84eb607d6c0 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -577,17 +577,11 @@ static int ohci_update_phy_reg(struct fw_card *card, int addr,
return ret;
}
-static int ar_context_add_page(struct ar_context *ctx)
+static void ar_context_link_page(struct ar_context *ctx,
+ struct ar_buffer *ab, dma_addr_t ab_bus)
{
- struct device *dev = ctx->ohci->card.device;
- struct ar_buffer *ab;
- dma_addr_t uninitialized_var(ab_bus);
size_t offset;
- ab = dma_alloc_coherent(dev, PAGE_SIZE, &ab_bus, GFP_ATOMIC);
- if (ab == NULL)
- return -ENOMEM;
-
ab->next = NULL;
memset(&ab->descriptor, 0, sizeof(ab->descriptor));
ab->descriptor.control = cpu_to_le16(DESCRIPTOR_INPUT_MORE |
@@ -606,6 +600,19 @@ static int ar_context_add_page(struct ar_context *ctx)
reg_write(ctx->ohci, CONTROL_SET(ctx->regs), CONTEXT_WAKE);
flush_writes(ctx->ohci);
+}
+
+static int ar_context_add_page(struct ar_context *ctx)
+{
+ struct device *dev = ctx->ohci->card.device;
+ struct ar_buffer *ab;
+ dma_addr_t uninitialized_var(ab_bus);
+
+ ab = dma_alloc_coherent(dev, PAGE_SIZE, &ab_bus, GFP_ATOMIC);
+ if (ab == NULL)
+ return -ENOMEM;
+
+ ar_context_link_page(ctx, ab, ab_bus);
return 0;
}
@@ -730,16 +737,17 @@ static __le32 *handle_ar_packet(struct ar_context *ctx, __le32 *buffer)
static void ar_context_tasklet(unsigned long data)
{
struct ar_context *ctx = (struct ar_context *)data;
- struct fw_ohci *ohci = ctx->ohci;
struct ar_buffer *ab;
struct descriptor *d;
void *buffer, *end;
+ __le16 res_count;
ab = ctx->current_buffer;
d = &ab->descriptor;
- if (d->res_count == 0) {
- size_t size, rest, offset;
+ res_count = ACCESS_ONCE(d->res_count);
+ if (res_count == 0) {
+ size_t size, size2, rest, pktsize, size3, offset;
dma_addr_t start_bus;
void *start;
@@ -750,29 +758,63 @@ static void ar_context_tasklet(unsigned long data)
*/
offset = offsetof(struct ar_buffer, data);
- start = buffer = ab;
+ start = ab;
start_bus = le32_to_cpu(ab->descriptor.data_address) - offset;
+ buffer = ab->data;
ab = ab->next;
d = &ab->descriptor;
- size = buffer + PAGE_SIZE - ctx->pointer;
+ size = start + PAGE_SIZE - ctx->pointer;
+ /* valid buffer data in the next page */
rest = le16_to_cpu(d->req_count) - le16_to_cpu(d->res_count);
+ /* what actually fits in this page */
+ size2 = min(rest, (size_t)PAGE_SIZE - offset - size);
memmove(buffer, ctx->pointer, size);
- memcpy(buffer + size, ab->data, rest);
- ctx->current_buffer = ab;
- ctx->pointer = (void *) ab->data + rest;
- end = buffer + size + rest;
+ memcpy(buffer + size, ab->data, size2);
+
+ while (size > 0) {
+ void *next = handle_ar_packet(ctx, buffer);
+ pktsize = next - buffer;
+ if (pktsize >= size) {
+ /*
+ * We have handled all the data that was
+ * originally in this page, so we can now
+ * continue in the next page.
+ */
+ buffer = next;
+ break;
+ }
+ /* move the next packet to the start of the buffer */
+ memmove(buffer, next, size + size2 - pktsize);
+ size -= pktsize;
+ /* fill up this page again */
+ size3 = min(rest - size2,
+ (size_t)PAGE_SIZE - offset - size - size2);
+ memcpy(buffer + size + size2,
+ (void *) ab->data + size2, size3);
+ size2 += size3;
+ }
- while (buffer < end)
- buffer = handle_ar_packet(ctx, buffer);
+ if (rest > 0) {
+ /* handle the packets that are fully in the next page */
+ buffer = (void *) ab->data +
+ (buffer - (start + offset + size));
+ end = (void *) ab->data + rest;
+
+ while (buffer < end)
+ buffer = handle_ar_packet(ctx, buffer);
- dma_free_coherent(ohci->card.device, PAGE_SIZE,
- start, start_bus);
- ar_context_add_page(ctx);
+ ctx->current_buffer = ab;
+ ctx->pointer = end;
+
+ ar_context_link_page(ctx, start, start_bus);
+ } else {
+ ctx->pointer = start + PAGE_SIZE;
+ }
} else {
buffer = ctx->pointer;
ctx->pointer = end =
- (void *) ab + PAGE_SIZE - le16_to_cpu(d->res_count);
+ (void *) ab + PAGE_SIZE - le16_to_cpu(res_count);
while (buffer < end)
buffer = handle_ar_packet(ctx, buffer);