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Ira W. Snyder 399f1e30ac kfifo: fix scatterlist usage ... The kfifo_dma family of functions use sg_mark_end() on the last element in their scatterlist. This forces use of a fresh scatterlist for each DMA operation, which makes recycling a single scatterlist impossible. Change the behavior of the kfifo_dma functions to match the usage of the dma_map_sg function. This means that users must respect the returned nents value. The sample code is updated to reflect the change. This bug is trivial to cause: call kfifo_dma_in_prepare() such that it prepares a scatterlist with a single entry comprising the whole fifo. This is the case when you map the entirety of a newly created empty fifo. This causes the setup_sgl() function to mark the first scatterlist entry as the end of the chain, no matter what comes after it. Afterwards, add and remove some data from the fifo such that another call to kfifo_dma_in_prepare() will create two scatterlist entries. It returns nents=2. However, due to the previous sg_mark_end() call, sg_is_last() will now return true for the first scatterlist element. This causes the sample code to print a single scatterlist element when it should print two. By removing the call to sg_mark_end(), we make the API as similar as possible to the DMA mapping API. All users are required to respect the returned nents. Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Cc: Stefani Seibold <stefani@seibold.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		15 years ago
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hw_breakpoint	percpu: Add __percpu sparse annotations to hw_breakpoint	15 years ago
kfifo	kfifo: fix scatterlist usage	15 years ago
kobject	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	15 years ago
kprobes	SAMPLES: kprobe_example: Make it print something on MIPS.	15 years ago
trace_events	debugfs: Change debuhgfs directory of trace-events-sample.h	16 years ago
tracepoints	tracing: Let tracepoints have data passed to tracepoint callbacks	15 years ago
Kconfig	kfifo: add example files to the kernel sample directory	15 years ago
Makefile	kfifo: add example files to the kernel sample directory	15 years ago