Re: [PATCH 3/4] libata: implement ATAPI drain buffer

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Tejun Heo wrote:
Misc ATAPI commands may try to transfer more bytes than requested.
For PIO which is performed by libata HSM, this is worked around by
draining extra bytes from __atapi_pio_bytes().

This patch implements drain buffer to perform draining for DMA and
PIO-over-DMA cases.  One page is allocated w/ GFP_DMA32 during libata
core layer initialization.  On host registration, this drain page is
DMA mapped and ATAPI_MAX_DRAIN_PAGES sg entries are reserved.

ata_sg_setup_extra() uses these extra sg entries to map the drain page
ATAPI_MAX_DRAIN_PAGES times, extending sg list by ATAPI_MAX_DRAIN
bytes.  This allows both DMA and PIO-over-DMA misc ATAPI commands to
overflow by ATAPI_MAX_DRAIN bytes just like PIO commands.

Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
 drivers/ata/libata-core.c |  116 ++++++++++++++++++++++++++++++++++++++++-----
 drivers/ata/libata-scsi.c |   14 ++++--
 include/linux/libata.h    |    4 +-
 3 files changed, 116 insertions(+), 18 deletions(-)


(updating status on an old patch)

dropped, due to your current work


-
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

[Index of Archives]     [Linux Filesystems]     [Linux SCSI]     [Linux RAID]     [Git]     [Kernel Newbies]     [Linux Newbie]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Samba]     [Device Mapper]

  Powered by Linux