From 823588c18689ddd49d4643eda7654302f18a275f Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Thu, 22 Jun 2006 22:27:14 +0100 Subject: [PATCH] [ARM] 3537/1: Rework DMA-bounce locking for finer granularity Patch from Kevin Hilman This time with IRQ versions of locks. Rework also enables compatability with realtime-preemption patch. With the current locking via interrupt disabling, under RT, potentially sleeping functions can be called with interrupts disabled. Signed-off-by: Kevin Hilman Signed-off-by: Deepak Saxena Signed-off-by: Russell King --- arch/arm/common/dmabounce.c | 67 ++++++++++++------------------------- 1 file changed, 21 insertions(+), 46 deletions(-) diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c index 7971d0dc689..5b7c26395b4 100644 --- a/arch/arm/common/dmabounce.c +++ b/arch/arm/common/dmabounce.c @@ -77,6 +77,8 @@ struct dmabounce_device_info { #endif struct dmabounce_pool small; struct dmabounce_pool large; + + rwlock_t lock; }; static LIST_HEAD(dmabounce_devs); @@ -116,6 +118,7 @@ alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, struct safe_buffer *buf; struct dmabounce_pool *pool; struct device *dev = device_info->dev; + unsigned long flags; dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n", __func__, ptr, size, dir); @@ -163,8 +166,12 @@ alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, print_alloc_stats(device_info); #endif + write_lock_irqsave(&device_info->lock, flags); + list_add(&buf->node, &device_info->safe_buffers); + write_unlock_irqrestore(&device_info->lock, flags); + return buf; } @@ -172,22 +179,32 @@ alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, static inline struct safe_buffer * find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr) { - struct safe_buffer *b; + struct safe_buffer *b = NULL; + unsigned long flags; + + read_lock_irqsave(&device_info->lock, flags); list_for_each_entry(b, &device_info->safe_buffers, node) if (b->safe_dma_addr == safe_dma_addr) - return b; + break; - return NULL; + read_unlock_irqrestore(&device_info->lock, flags); + return b; } static inline void free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf) { + unsigned long flags; + dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf); + write_lock_irqsave(&device_info->lock, flags); + list_del(&buf->node); + write_unlock_irqrestore(&device_info->lock, flags); + if (buf->pool) dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr); else @@ -396,7 +413,6 @@ dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size, enum dma_data_direction dir) { - unsigned long flags; dma_addr_t dma_addr; dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", @@ -404,12 +420,8 @@ dma_map_single(struct device *dev, void *ptr, size_t size, BUG_ON(dir == DMA_NONE); - local_irq_save(flags); - dma_addr = map_single(dev, ptr, size, dir); - local_irq_restore(flags); - return dma_addr; } @@ -424,25 +436,18 @@ void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, enum dma_data_direction dir) { - unsigned long flags; - dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", __func__, (void *) dma_addr, size, dir); BUG_ON(dir == DMA_NONE); - local_irq_save(flags); - unmap_single(dev, dma_addr, size, dir); - - local_irq_restore(flags); } int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { - unsigned long flags; int i; dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", @@ -450,8 +455,6 @@ dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, BUG_ON(dir == DMA_NONE); - local_irq_save(flags); - for (i = 0; i < nents; i++, sg++) { struct page *page = sg->page; unsigned int offset = sg->offset; @@ -462,8 +465,6 @@ dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, map_single(dev, ptr, length, dir); } - local_irq_restore(flags); - return nents; } @@ -471,7 +472,6 @@ void dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { - unsigned long flags; int i; dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", @@ -479,55 +479,38 @@ dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, BUG_ON(dir == DMA_NONE); - local_irq_save(flags); - for (i = 0; i < nents; i++, sg++) { dma_addr_t dma_addr = sg->dma_address; unsigned int length = sg->length; unmap_single(dev, dma_addr, length, dir); } - - local_irq_restore(flags); } void dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size, enum dma_data_direction dir) { - unsigned long flags; - dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", __func__, (void *) dma_addr, size, dir); - local_irq_save(flags); - sync_single(dev, dma_addr, size, dir); - - local_irq_restore(flags); } void dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size, enum dma_data_direction dir) { - unsigned long flags; - dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", __func__, (void *) dma_addr, size, dir); - local_irq_save(flags); - sync_single(dev, dma_addr, size, dir); - - local_irq_restore(flags); } void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { - unsigned long flags; int i; dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", @@ -535,23 +518,18 @@ dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, BUG_ON(dir == DMA_NONE); - local_irq_save(flags); - for (i = 0; i < nents; i++, sg++) { dma_addr_t dma_addr = sg->dma_address; unsigned int length = sg->length; sync_single(dev, dma_addr, length, dir); } - - local_irq_restore(flags); } void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { - unsigned long flags; int i; dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", @@ -559,16 +537,12 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, BUG_ON(dir == DMA_NONE); - local_irq_save(flags); - for (i = 0; i < nents; i++, sg++) { dma_addr_t dma_addr = sg->dma_address; unsigned int length = sg->length; sync_single(dev, dma_addr, length, dir); } - - local_irq_restore(flags); } static int @@ -622,6 +596,7 @@ dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size, device_info->dev = dev; INIT_LIST_HEAD(&device_info->safe_buffers); + rwlock_init(&device_info->lock); #ifdef STATS device_info->total_allocs = 0; -- 2.41.0