Re: Issues with commit 34b48db6 ("block: remove artifical max_hw_sectors cap")
From: Christoph Hellwig <hch@lst.de>
Date: 2015-01-05 17:18:40
Also in:
linux-scsi
Possibly related (same subject, not in this thread)
- 2014-12-30 · Re: Issues with commit 34b48db6 ("block: remove artifical max_hw_sectors cap") · James Bottomley <James.Bottomley@HansenPartnership.com>
- 2014-12-30 · Re: Issues with commit 34b48db6 ("block: remove artifical max_hw_sectors cap") · Alan Stern <stern@rowland.harvard.edu>
- 2014-12-30 · Re: Issues with commit 34b48db6 ("block: remove artifical max_hw_sectors cap") · James Bottomley <hidden>
On Tue, Dec 30, 2014 at 11:19:07AM -0500, Douglas Gilbert wrote:
In SCSI, the VPD page 0xb0 (Block limits) has a "Maximum transfer length" field (32 bits long). Its units are logical blocks. Useful if >0 as 0 means "unreported". USB to SATA bridges should comply with SAT. However SAT and SAT-2 don't even mention that VPD page. SAT-3 and SAT-4 mention that page but have "unspecified" next to that field. Basically useless.
Maybe we need to cap the max sectors value to something fairly low unless we have the block limits VPD page and it contains useful information.