On Monday 07 January 2008 17:37:41 Tejun Heo wrote: > Rusty Russell wrote: > > Hi Tejun, > > > > Nice try! Even ignoring the ugliness of undoing such an operation if > > the caller doesn't expect you to mangle their chains, consider a > > one-element sg array. :( > > Heh heh, that can be dealt with by skipping the first chain if the first > chain is empty after chaining. Please take a look at > ata_sg_setup_extra() in the following. > > http://git.kernel.org/?p=linux/kernel/git/tj/libata-dev.git;a=blob;f=driver >s/ata/libata-core.c;h=32dde5bbc75ed53e89ac17040da2cd0621a37161;hb=c8847e473a >4a2844244784226eb362be10d52ce9 > > That said, yeah, it's seriously ugly. Restoring the original sg is ugly > too. I definitely agree that we need some improvements here. Erk, that's beyond ugly, into actual evil. To make this general you need to find the last N 1-element chains (but SCSI doesn't do this of course). Oh the horror... I'd be remiss if I didn't mention that the sg_ring ata patches were straightforward, and indescribably beautiful if compared to this! Thanks, Rusty. - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
