Re: [PATCH] ata: do not hard code limit in ata_set_lba_range_entries()

On Tue, Aug 23, 2016 at 3:37 AM, Tom Yan [off-list ref] wrote:

On 23 August 2016 at 07:30, Shaun Tancheff [off-list ref] wrote:

If we really want/need to avoid hitting some real buffer limit (e.g.
maximum length of scatter/gather list?), then we should in some way
check n_block against that. If it is too large we then return
used_bytes = 0 (optionally with some follow-up to add a response to
such return value or so).

Yes there is a real buffer limit, I can think of these two options:
1- Assume the setups from sd_setup_discard_cmnd() and/
   or sd_setup_write_same_cmnd() are providing an sglist of
   sdp->sector_size via scsi_init_io()

2- Find (or write) a suitable sg_get_size(sgl, nents) to walk the
    sglist and calculate the available buffer size.

#2 sounds like more fun but I'm not sure it's what people would prefer to see.

--
Shaun