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| author | Kristian Høgsberg, Stefan Richter <stefanr@s5r6.in-berlin.de> | 2007-05-09 19:23:10 -0400 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2007-05-10 18:24:14 +0200 |
| commit | 36abb3b18e26bf980e8529512853c5d73971a48b (patch) | |
| tree | b7c48e26816a1b9e86249dee39968f4ac3c3f68a /drivers/firewire/fw-sbp2.c | |
| parent | e1b68c4dcfb8bb7d79b6771e48767039ffbe00a8 (diff) | |
| download | lwn-36abb3b18e26bf980e8529512853c5d73971a48b.tar.gz lwn-36abb3b18e26bf980e8529512853c5d73971a48b.zip | |
firewire: Add a comment to describe why we split the sg list.
Signed-off-by: Kristian Hoegsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'drivers/firewire/fw-sbp2.c')
| -rw-r--r-- | drivers/firewire/fw-sbp2.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c index 07be24e2d201..cb808d525314 100644 --- a/drivers/firewire/fw-sbp2.c +++ b/drivers/firewire/fw-sbp2.c @@ -926,7 +926,10 @@ static int sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb) /* * Convert the scatterlist to an sbp2 page table. If any - * scatterlist entries are too big for sbp2 we split the as we go. + * scatterlist entries are too big for sbp2, we split them as we + * go. Even if we ask the block I/O layer to not give us sg + * elements larger than 65535 bytes, some IOMMUs may merge sg elements + * during DMA mapping, and Linux currently doesn't prevent this. */ for (i = 0, j = 0; i < count; i++) { sg_len = sg_dma_len(sg + i); |