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Commit 837596a6 authored by Clemens Ladisch's avatar Clemens Ladisch Committed by Stefan Richter
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firewire: ohci: avoid reallocation of AR buffers 



Freeing an AR buffer page just to allocate a new page immediately
afterwards is not only a pointless effort but also dangerous because
the allocation can fail, which would result in an oops later.

Split ar_context_add_page() into two functions so that we can reuse
the old page directly.

Signed-off-by: default avatarClemens Ladisch <clemens@ladisch.de>
Tested-by: default avatarMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent a1f805e5

drivers/firewire/ohci.c

+16 −12
Original line number Original line Diff line number Diff line
@@ -577,17 +577,11 @@ static int ohci_update_phy_reg(struct fw_card *card, int addr, 
	return ret;

	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;

	size_t offset;





	ab = dma_alloc_coherent(dev, PAGE_SIZE, &ab_bus, GFP_ATOMIC);

	if (ab == NULL)

		return -ENOMEM;



	ab->next = NULL;

	ab->next = NULL;

	memset(&ab->descriptor, 0, sizeof(ab->descriptor));

	memset(&ab->descriptor, 0, sizeof(ab->descriptor));

	ab->descriptor.control        = cpu_to_le16(DESCRIPTOR_INPUT_MORE |

	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);

	reg_write(ctx->ohci, CONTROL_SET(ctx->regs), CONTEXT_WAKE);

	flush_writes(ctx->ohci);

	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;

	return 0;

}

}
@@ -730,7 +737,6 @@ static __le32 *handle_ar_packet(struct ar_context *ctx, __le32 *buffer) 
static void ar_context_tasklet(unsigned long data)

static void ar_context_tasklet(unsigned long data)

{

{

	struct ar_context *ctx = (struct ar_context *)data;

	struct ar_context *ctx = (struct ar_context *)data;

	struct fw_ohci *ohci = ctx->ohci;

	struct ar_buffer *ab;

	struct ar_buffer *ab;

	struct descriptor *d;

	struct descriptor *d;

	void *buffer, *end;

	void *buffer, *end;
@@ -799,9 +805,7 @@ static void ar_context_tasklet(unsigned long data) 
			ctx->current_buffer = ab;

			ctx->current_buffer = ab;

			ctx->pointer = end;

			ctx->pointer = end;





			dma_free_coherent(ohci->card.device, PAGE_SIZE,

			ar_context_link_page(ctx, start, start_bus);

					  start, start_bus);

			ar_context_add_page(ctx);

		} else {

		} else {

			ctx->pointer = start + PAGE_SIZE;

			ctx->pointer = start + PAGE_SIZE;

		}

		}