rapidio/tsi721_dma: fix failure to obtain transaction descriptor
authorAlexandre Bounine <alexandre.bounine@idt.com>
Wed, 30 Jul 2014 23:08:26 +0000 (16:08 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 31 Jul 2014 00:16:13 +0000 (17:16 -0700)
commit0193ed8225e1a79ed64632106ec3cc81798cb13c
tree130e54dc330c11d9e7baf1fe54f9cb84139f1a13
parentb104a35d32025ca740539db2808aa3385d0f30eb
rapidio/tsi721_dma: fix failure to obtain transaction descriptor

This is a bug fix for the situation when function tsi721_desc_get() fails
to obtain a free transaction descriptor.

The bug usually results in a memory access crash dump when data transfer
scatter-gather list has more entries than size of hardware buffer
descriptors ring.  This fix ensures that error is properly returned to a
caller instead of an invalid entry.

This patch is applicable to kernel versions starting from v3.5.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Cc: Stef van Os <stef.van.os@prodrive-technologies.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org> [3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/rapidio/devices/tsi721_dma.c