linux-toradex.git/kernel/kfifo.c, branch v2.6.39-rc2

kfifo: fix scatterlist usage

2010-10-01T17:50:58+00:00

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 
Cc: Stefani Seibold 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: implement missing __kfifo_skip_r()

2010-08-20T16:34:54+00:00

kfifo_skip() is currently broken, due to the missing of the internal
helper function.  Add it.

Signed-off-by: Andrea Righi 
Cc: Greg KH 
Acked-by: Stefani Seibold 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kernel/kfifo.c: add handling of chained scatterlists

2010-08-12T15:43:29+00:00

The current kfifo scatterlist implementation will not work with chained
scatterlists.  It assumes that struct scatterlist arrays are allocated
contiguously, which is not the case when chained scatterlists (struct
sg_table) are in use.

Signed-off-by: Stefani Seibold 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: replace the old non generic API

2010-08-11T15:59:23+00:00

Simply replace the whole kfifo.c and kfifo.h files with the new generic
version and fix the kerneldoc API template file.

Signed-off-by: Stefani Seibold 
Cc: Greg KH 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: Don't use integer as NULL pointer

2010-02-16T23:11:08+00:00

This patch fixes following sparse warnings:

include/linux/kfifo.h:127:25: warning: Using plain integer as NULL pointer
kernel/kfifo.c:83:21: warning: Using plain integer as NULL pointer

Signed-off-by: Anton Vorontsov 
Acked-by: Stefani Seibold 
Signed-off-by: Greg Kroah-Hartman

kfifo: Make kfifo_initialized work after kfifo_free

2010-02-16T23:11:06+00:00

After kfifo rework it's no longer possible to reliably know if kfifo is
usable, since after kfifo_free(), kfifo_initialized() would still return
true. The correct behaviour is needed for at least FHCI USB driver.

This patch fixes the issue by resetting the kfifo to zero values (the
same approach is used in kfifo_alloc() if allocation failed).

Signed-off-by: Anton Vorontsov 
Acked-by: Stefani Seibold 
Signed-off-by: Greg Kroah-Hartman

kfifo: fix kernel-doc notation

2010-02-03T02:11:21+00:00

Fix kfifo kernel-doc warnings:

Warning(kernel/kfifo.c:361): No description found for parameter 'total'
Warning(kernel/kfifo.c:402): bad line:  @ @lenout: pointer to output variable with copied data
Warning(kernel/kfifo.c:412): No description found for parameter 'lenout'

Signed-off-by: Randy Dunlap 
Cc: Stefani Seibold 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: document everywhere that size has to be power of two

2010-01-16T20:15:38+00:00

On my first try using them I missed that the fifos need to be power of
two, resulting in a runtime bug.  Document that requirement everywhere
(and fix one grammar bug)

Signed-off-by: Andi Kleen 
Acked-by: Stefani Seibold 
Cc: Roland Dreier 
Cc: Dmitry Torokhov 
Cc: Andy Walls 
Cc: Vikram Dhillon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: add kfifo_out_peek

2010-01-16T20:15:38+00:00

In some upcoming code it's useful to peek into a FIFO without permanentely
removing data.  This patch implements a new kfifo_out_peek() to do this.

Signed-off-by: Andi Kleen 
Acked-by: Stefani Seibold 
Cc: Roland Dreier 
Cc: Dmitry Torokhov 
Cc: Andy Walls 
Cc: Vikram Dhillon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: sanitize *_user error handling

2010-01-16T20:15:38+00:00

Right now for kfifo_*_user it's not easily possible to distingush between
a user copy failing and the FIFO not containing enough data.  The problem
is that both conditions are multiplexed into the same return code.

Avoid this by moving the "copy length" into a separate output parameter
and only return 0/-EFAULT in the main return value.

I didn't fully adapt the weird "record" variants, those seem
to be unused anyways and were rather messy (should they be just removed?)

I would appreciate some double checking if I did all the conversions
correctly.

Signed-off-by: Andi Kleen 
Cc: Stefani Seibold 
Cc: Roland Dreier 
Cc: Dmitry Torokhov 
Cc: Andy Walls 
Cc: Vikram Dhillon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds