linux-toradex.git/lib/scatterlist.c, branch v4.4.93

scatterlist: allow limited chaining without ARCH_HAS_SG_CHAIN

2015-08-17T14:12:51+00:00

There are a couple of uses of struct scatterlist that never go to
the dma_map_sg() helper and thus don't care about ARCH_HAS_SG_CHAIN
which indicates that we can map chained S/G list.

The most important one is the crypto code, which currently has
to open code a few helpers to always allow chaining.  This patch
removes a few #ifdef ARCH_HAS_SG_CHAIN statements so that we can
switch the crypto code to these common helpers.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

drivers/scsi/scsi_debug.c: resolve sg buffer const-ness issue

2015-07-01T02:44:59+00:00

do_device_access() takes a separate parameter to indicate the direction of
data transfer, which it used to use to select the appropriate function out
of sg_pcopy_{to,from}_buffer().  However these two functions now have

So this patch makes it bypass these wrappers and call the underlying
function sg_copy_buffer() directly; this has the same calling style as
do_device_access() i.e.  a separate direction-of-transfer parameter and no
pointers-to-const, so skipping the wrappers not only eliminates the
warning, it also make the code simpler :)

[akpm@linux-foundation.org: fix very broken build]
Signed-off-by: Dave Gordon 
Acked-by: Arnd Bergmann 
Cc: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/scatterlist: mark input buffer parameters as 'const'

2015-07-01T02:44:59+00:00

The 'buf' parameter of sg(p)copy_from_buffer() can and should be
const-qualified, although because of the shared implementation of
_to_buffer() and _from_buffer(), we have to cast this away internally.

This means that callers who have a 'const' buffer containing the data to
be copied to the sg-list no longer have to cast away the const-ness
themselves.  It also enables improved coverage by code analysis tools.

Signed-off-by: Dave Gordon 
Cc: Akinobu Mita 
Cc: "Martin K. Petersen" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/scatterlist.c: fix kerneldoc for sg_pcopy_{to,from}_buffer()

2015-07-01T02:44:59+00:00

The kerneldoc for the functions doesn't match the code; the last two
parameters (buflen, skip) have been transposed, which is confusing,
especially as they're both integral types and the compiler won't warn
about swapping them.

These functions and the kerneldoc were introduced in commit:
    df642cea lib/scatterlist: introduce sg_pcopy_from_buffer() ...
    Author: Akinobu Mita 
    Date:   Mon Jul 8 16:01:54 2013 -0700

    The only difference between sg_pcopy_{from,to}_buffer() and
    sg_copy_{from,to}_buffer() is an additional argument that
    specifies the number of bytes to skip the SG list before
    copying.

The functions have the extra argument at the end, but the kerneldoc
lists it in penultimate position.

Signed-off-by: Dave Gordon 
Reviewed-by: Akinobu Mita 
Cc: "Martin K. Petersen" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

scatterlist: introduce sg_nents_for_len

2015-06-03T02:51:27+00:00

When performing a dma_map_sg() call, the number of sg entries to map is
required. Using sg_nents to retrieve the number of sg entries will
return the total number of entries in the sg list up to the entry marked
as the end. If there happen to be unused entries in the list, these will
still be counted. Some dma_map_sg() implementations will not handle the
unused entries correctly (lib/swiotlb.c) and execute a BUG_ON.

The sg_nents_for_len() function will traverse the sg list and return the
number of entries required to satisfy the supplied length argument. This
can then be supplied to the dma_map_sg() call to successfully map the
sg.

Signed-off-by: Tom Lendacky 
Signed-off-by: Herbert Xu

lib/scatterlist: fix memory leak with scsi-mq

2014-10-28T16:27:10+00:00

Fix a memory leak with scsi-mq triggered by commands with large data
transfer length.

Fixes: c53c6d6a68b1 ("scatterlist: allow chaining to preallocated chunks")
Cc:  # 3.17.x
Signed-off-by: Tony Battersby 
Reviewed-by: Martin K. Petersen 
Signed-off-by: Jens Axboe

lib/scatterlist: make ARCH_HAS_SG_CHAIN an actual Kconfig

2014-08-08T22:57:26+00:00

Rather than have architectures #define ARCH_HAS_SG_CHAIN in an
architecture specific scatterlist.h, make it a proper Kconfig option and
use that instead.  At same time, remove the header files are are now
mostly useless and just include asm-generic/scatterlist.h.

[sfr@canb.auug.org.au: powerpc files now need asm/dma.h]
Signed-off-by: Laura Abbott 
Acked-by: Thomas Gleixner 			[x86]
Acked-by: Benjamin Herrenschmidt 	[powerpc]
Acked-by: Heiko Carstens 
Cc: Russell King 
Cc: Tony Luck 
Cc: Fenghua Yu 
Cc: Paul Mackerras 
Cc: Ingo Molnar 
Cc: "H. Peter Anvin" 
Cc: "James E.J. Bottomley" 
Cc: Martin Schwidefsky 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

scatterlist: allow chaining to preallocated chunks

2014-07-25T21:16:21+00:00

Blk-mq drivers usually preallocate their S/G list as part of the request,
but if we want to support the very large S/G lists currently supported by
the SCSI code that would tie up a lot of memory in the preallocated request
pool.  Add support to the scatterlist code so that it can initialize a
S/G list that uses a preallocated first chunks and dynamically allocated
additional chunks.  That way the scsi-mq code can preallocate a first
page worth of S/G entries as part of the request, and dynamically extend
the S/G list when needed.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Webb Scales 
Acked-by: Jens Axboe 
Tested-by: Bart Van Assche 
Tested-by: Robert Elliott

lib/scatterlist: export sg_miter_skip()

2013-12-09T01:56:37+00:00

sg_copy_buffer() can't meet demand for some drrivers(such usb
mass storage), so we have to use the sg_miter_* APIs to access
sg buffer, then need export sg_miter_skip() for these drivers.

The API is needed for converting to sg_miter_* APIs in USB storage
driver for accessing sg buffer.

Acked-by: Andrew Morton 
Cc: FUJITA Tomonori 
Cc: Jens Axboe 
Signed-off-by: Ming Lei 
Reviewed-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

lib/scatterlist.c: don't flush_kernel_dcache_page on slab page

2013-10-31T23:58:13+00:00

Commit b1adaf65ba03 ("[SCSI] block: add sg buffer copy helper
functions") introduces two sg buffer copy helpers, and calls
flush_kernel_dcache_page() on pages in SG list after these pages are
written to.

Unfortunately, the commit may introduce a potential bug:

 - Before sending some SCSI commands, kmalloc() buffer may be passed to
   block layper, so flush_kernel_dcache_page() can see a slab page
   finally

 - According to cachetlb.txt, flush_kernel_dcache_page() is only called
   on "a user page", which surely can't be a slab page.

 - ARCH's implementation of flush_kernel_dcache_page() may use page
   mapping information to do optimization so page_mapping() will see the
   slab page, then VM_BUG_ON() is triggered.

Aaro Koskinen reported the bug on ARM/kirkwood when DEBUG_VM is enabled,
and this patch fixes the bug by adding test of '!PageSlab(miter->page)'
before calling flush_kernel_dcache_page().

Signed-off-by: Ming Lei 
Reported-by: Aaro Koskinen 
Tested-by: Simon Baatz 
Cc: Russell King - ARM Linux 
Cc: Will Deacon 
Cc: Aaro Koskinen 
Acked-by: Catalin Marinas 
Cc: FUJITA Tomonori 
Cc: Tejun Heo 
Cc: "James E.J. Bottomley" 
Cc: Jens Axboe 
Cc: 	[3.2+]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds