On Wed, 2008-01-09 at 14:13 +0900, Tejun Heo wrote: > James Bottomley wrote: > >> Also, DMA alignment at > >> block layer isn't enough for ATA. ATA needs drain buffers for ATAPI > >> commands with variable length response. :-( > > > > OK, where is this in the libata code? The dma_pad size is only 4 bytes, > > so this drain, I assume is only a word long? Given the word alignment > > requirements of ATA doesn't this still mean it's only draining up to the > > word boundary anyway (so the code is still correct)? > > Patch is acked but not merged yet. > > http://git.kernel.org/?p=linux/kernel/git/tj/libata-dev.git;a=commit;h=6cd22a0febc74bebe52d58eb22271b8770892a2d > > The full function can be read from the following. It's > ata_sg_setup_extra(). > > http://git.kernel.org/?p=linux/kernel/git/tj/libata-dev.git;a=blob;f=drivers/ata/libata-core.c;h=d763c072e6cefc724ea24cb68a7adf47b340f054;hb=6cd22a0febc74bebe52d58eb22271b8770892a2d OK, but that patch was sent to the mailing list on 4 Jan ... five days after this one. It's a little hard to take unposted patches into account ... It's a fairly comprehensive merge clash ... where is this drain patch on the upstream track? because currently ipr and aic94xx panic the system without the dma padding removal (I just figured -rc6 was a bit late for major surgery like this, but I was planning a backport if it stood up in 2.6.24). James - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
