ioatdma: fix race between updating ioat->head and IOAT_COMPLETION_PENDING

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There is a race that can hit during __cleanup() when the ioat->head pointer is
incremented during descriptor submission. The __cleanup() can clear the
PENDING flag when it does not see any active descriptors. This causes new
submitted descriptors to be ignored because the COMPLETION_PENDING flag is
cleared. This was introduced when code was adapted from ioatdma v1 to ioatdma
v2. For v2 and v3, IOAT_COMPLETION_PENDING flag will be abandoned and a new
flag IOAT_CHAN_ACTIVE will be utilized. This flag will also be protected under
the prep_lock when being modified in order to avoid the race.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <djbw@fb.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

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Dave Jiang 2013-02-07 14:38:32 -07:00 • committed by Vinod Koul

parent cfdf5b6cc5

commit 4dec23d771

3 changed files with 128 additions and 97 deletions

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1

drivers/dma/ioat/dma.h

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113

drivers/dma/ioat/dma_v2.c

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111

drivers/dma/ioat/dma_v3.c

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